Cytomegalovirus: detection of DNA and IgG and IgM antibodies

The most common method for detecting CMV (cytomegalovirus infection) is a blood test for cytomegalovirus. There are various pathogen detection techniques that can reliably determine the presence of the pathogen. Most tests are based on the detection of specific antibodies produced by the body in response to the pathogen. PCR diagnostics are also possible, which provides information about the presence of pathogen DNA in the blood, allows one to assess the activity of the infectious process and the degree of spread of the pathogen in the body.

The most common method for detecting CMV (cytomegalovirus infection) is a blood test for cytomegalovirus. There are various pathogen detection techniques that can reliably determine the presence of the pathogen. Most tests are based on the detection of specific antibodies produced by the body in response to the pathogen. PCR diagnostics are also possible, which provides information about the presence of pathogen DNA in the blood, allows one to assess the activity of the infectious process and the degree of spread of the pathogen in the body.

Human cytomegalovirus infection is a viral anthroponotic disease that affects almost the entire body. It is characterized by a wide variability of forms and symptoms - from asymptomatic carriage to severe damage to the respiratory, excretory and other body systems.

Causative agents of infection, its sources

Cytomegalovirus (Cytomegalovirus hominis) belongs to the genus of DNA viruses, is distinguished by its large virion size (up to 300 nm), and is part of the herpesvirus family. Several strains of the pathogen have been registered:

The source of infection is the patient or the carrier. The pathogen is detected in biological fluids and secretions. Routes of entry of the virus:

• Davis.
• Kerr.
• AD-169.
• Towne 125.

Most strains are little studied, but it is reliably known that all of them can reproduce without destroying the host cell. The virus can survive for a long time at room temperature, but is sensitive to heat and the action of disinfectants.

1. Airborne.
2. Contact.
3. Food.
4. Parenteral and transplacental.

According to statistics, the infection rate is up to 95%, depending on the region and country.

What is cytomegalovirus? Cytomegalovirus (CMV) is a member of the herpesvirus family, which includes herpes simplex viruses, varicella-zoster virus, and Epstein-Bar virus (the causative agent of infectious mononucleosis). The cytomegalovirus virus is widespread throughout the world in all socioeconomic groups, but is more common in developing countries in areas with low levels of socioeconomic development.

The virus is found in various biological fluids of the human body, including urine, saliva, breast milk, blood, tears, semen and vaginal discharge. Once a virus enters the body, in most cases it remains there for life. Most often, infection with the virus does not manifest itself in any way. Cytomegalovirus can cause death and illness in fetuses and newborns, and illness in people with weakened immune systems (organ transplant recipients, AIDS patients, and cancer patients)

How common is cytomegalovirus infection? About 80% of adults under 40 years of age are infected with cytomegaly virus. Approximately 1 in 150 children is born with congenital cytomegalovirus infection. Approximately 1 in 750 children are born with diseases associated with cytomegalovirus infection.

How can you become infected with cytomegalovirus? Transmission of cytomegalovirus occurs from person to person through contact with infected biological fluid (urine, saliva (saliva), breast milk, blood, tears, semen, and vaginal discharge) but the likelihood of infection from a single accidental contact is negligible. Approximately 1% to 4% of pregnant women become infected with cytomegalovirus during pregnancy, and one third of them have intrauterine infection of the fetus. No measures can completely eliminate the risk of intrauterine infection, but simple rules (more about them below) can significantly reduce its risk.

What are the signs of cytomegalovirus infection? Most healthy children and adults infected with CMV do not have any symptoms of infection and do not even know that they are infected. Symptoms may include fever, fatigue, sore throat, and enlarged tonsils, but these symptoms are also common to many other infectious diseases, so most people cannot remember when they became infected with cytomegalovirus.

Most newborns with congenital cytomegalovirus infection never develop symptoms of CMV, some have so-called temporary manifestations that disappear without a trace over time, and in a small number, signs of congenital CMV are pronounced and remain for life.

Temporary symptoms of CMV in newborns: 1. Liver damage 2. Spleen damage 3. Jaundice (skin and mucous membranes of the eyes) 4. Spotty rash on the skin (bluish-purple color) 5. Lung damage 6. Low weight

Persistent symptoms of CMV in newborns: 1. Hearing loss 2. Vision loss 3. Mental retardation 4. Small head 5. Loss of coordination 6. Death

In some children, permanent signs of CMV do not appear immediately after birth, but appear several months or even years later. The most common are hearing and vision loss. Therefore, it is important to know whether a newborn has been infected with cytomegalovirus in order to conduct regular examinations of his hearing and vision in the first months and years of his life.

How is cytomegalovirus diagnosed in pregnant women and newborns? Testing all pregnant women for CMV is not currently recommended worldwide. The test can help you find out if you have ever been infected with this virus. A test for so-called IgG antibodies will show whether your body has developed antibodies against cytomegalovirus. If you are pregnant and have positive IgG antibodies against cytomegalovirus, then the chance of transmitting the virus from you to the fetus is negligible, unless you became infected with CMV in the previous few months of pregnancy. Other tests for IgM and avid IgG antibodies can help determine how long ago the virus was infected.

If a pregnant woman does not have IgG antibodies against cytomegalovirus and there are no other types of antibodies (IgM and avid IgG), then the child has a high chance of becoming infected during pregnancy if the mother becomes infected. Therefore, pregnant women with the absence (negative results) of antibodies against cytomegalovirus should exercise caution when in contact with small children, since cytomegalovirus is often (up to 40%) detected in their saliva and urine. The simplest rules are not to kiss children on the lips and wash your hands thoroughly after contact with them.

If a doctor observing a pregnant woman decides that she became infected with cytomegalovirus during pregnancy, this does not mean that the unborn child will be infected. In these cases, it is possible to conduct more thorough examinations (amniocentesis) in order to find out whether the fetus is infected or not. In the vast majority of cases, children born with CMV develop normally. For these reasons, CMV testing is not recommended as mandatory.

Why test CMV when planning pregnancy? If you are planning a pregnancy, then a CMV test will help you assess how careful you need to be regarding CMV during pregnancy. If you test positive for IgG, then you will know that there is a negligible chance of intrauterine cytomegalovirus infection; if the test for IgG is negative, then carefully follow the recommendations outlined in this article.

How are newborns screened for CMV? If you find out that you are infected with CMV for the first time during your pregnancy, you should make sure that your baby is infected after birth. The diagnosis of congenital cytomegalovirus infection in a newborn is made when cytomegalovirus is directly isolated from urine, blood, or saliva (by PCR or culture) within 3 weeks after birth. Testing for antibodies (IgM, IgG) is not used . Most often, children infected during pregnancy develop as normal children, but during the first years of life you should regularly check their vision and hearing.

How is cytomegalovirus infection treated? Currently, there are no drugs or vaccines that can prevent intrauterine infection of the fetus with cytomegalovirus. There is evidence that the use of the drug ganciclovir can prevent hearing loss in children with congenital CMV, but this drug has serious side effects and should be prescribed for life-threatening conditions.

How can I find out if I have ever been infected with CMV? A test for IgG antibodies, if positive, can determine that you have ever been infected with cytomegalovirus infection, but it will not show whether you were infected during pregnancy and will not determine whether the fetus is infected with CMV. If you test negative for IgG antibodies against cytomegalovirus, you should be careful to prevent CMV infection during pregnancy.

How can I find out if I am infected with CMV during pregnancy? This can be found out by conducting a test for IgG antibodies after a certain period of time. If the first examination shows a negative result, and the second one is positive, then you were infected with the virus during pregnancy. There is a test that can determine infection during pregnancy using a single test (determination of avid IgG). Another way is to determine IgM antibodies, which exist in the blood for 30-60 days after the initial infection with the virus and then disappear. The study must be carried out in conjunction with the determination of IgG antibodies

How can I find out if the fetus is infected? Since there are currently no effective drugs to treat CMV-infected pregnant women, there is no point in conducting studies to determine whether the fetus is infected. Testing is sometimes performed in pregnant women with primary CMV infection during pregnancy, as they are at high risk (33%) of transmitting the virus to the fetus. Examination of the amniotic fluid or blood of the fetus together with an ultrasound examination can often reveal whether the fetus is infected with CMV or not. However, these surveys are dangerous and not always accurate.

How can I tell if a newborn has congenital CMV? The diagnosis of congenital cytomegalovirus infection in a newborn is made when cytomegalovirus is directly isolated from urine, blood, or saliva (using PCR or culture methods) within 3 weeks after birth. Testing for antibodies (IgM, IgG) is not used to make a diagnosis. If your child is diagnosed with congenital CMV, you should have his or her hearing and vision examined regularly, but in most cases, children with congenital CMV develop normally. Congenital cytomegalovirus infection cannot be established even if a test for the direct determination of cytomegalovirus was carried out in a newborn later than 3 weeks after birth.

Should I be tested for CMV if I am planning a pregnancy? If you are planning a pregnancy, then a CMV test will help you assess how careful you need to be regarding CMV during pregnancy. If you test positive for IgG, then you will know that there is a negligible chance of intrauterine cytomegalovirus infection; if the test for IgG is negative, then carefully follow the recommendations outlined in this article.

How can you prevent CMV infection during pregnancy? Women with negative IgG test results (seronegative) are most likely to become infected during pregnancy. No measure can completely eliminate the risk of infection, but following these rules will reduce the likelihood of CMV infection.

1. Wash your hands thoroughly with soap for 15-20 minutes, especially after changing diapers (pampers) for infants 2. Never kiss children under 5 years of age on the lips 3. Provide separate dishes and cutlery for yourself and small children 4. If you work in child care institutions (nurseries, kindergartens) during pregnancy, take a vacation or sharply limit contact with children.

If I already have a child with congenital CMV, will my next child also be infected? Almost all women who have one child with congenital CMV are protected from cytomegalovirus infection because they have already developed immunity to CMV.

Source: based on materials from the website www.venuro.info

Classification

There is no globally accepted classification system for cytomegalovirus infection (CMVI). In practice, the classification developed in 1980 is used. According to this system, CMVI is divided into:

1. Congenital, can be acute, chronic.
2. Acquired, can be acute, latent, generalized.

CMV infection is classified according to the duration of its course:

• Spicy.
• Protracted
• Chronic
• Recurrent.

Depending on the severity of the course, there are mild, moderate, and severe forms of the course.

The mechanism of the onset and development of the disease

The virus enters the body through the mucous epithelium of various organs. The free presence of viral particles in the bloodstream quickly ends with the introduction of the pathogen into mononuclear-type phagocytes. The initial replication of cytomegalovirus occurs in them.

Infected cells enlarge, and large intranuclear inclusions, which are accumulations of viral bodies, can be found in them. An increase in the number of affected cells is manifested by the development of multiple nodular infiltrates or calcifications in the tissues. The pathogen reproduces especially actively in the salivary glands , where it is easiest to detect.

The pathogen can persist in cells for a long time; the only manifestation of infection is suppression of cellular immunity. In most, the disease proceeds latently and becomes an asymptomatic carrier.

Exacerbation of CMV infection occurs in patients with suppressed immunity. The most common reasons for weakening the body's defenses:

• Taking immunosuppressants.
• HIV infection.
• Pregnancy.

As a result, the virus is activated, active reproduction of the pathogen begins in all organs and tissues, and the clinic of one of the forms of the disease develops. Severe CMV infections are in most cases associated with HIV infection.

Clinical manifestations of cytomegalovirus

The incubation period for cytomegalovirus ranges from 20 to 60 days. The acute phase of the disease lasts from 2 to 6 weeks: an increase in body temperature and the appearance of signs of general intoxication, chills, weakness, headache, muscle pain and bronchitis. In response to the initial introduction, immune restructuring of the body develops. After the acute phase, asthenia and sometimes autonomic-vascular disorders persist for many weeks. Multiple damage to internal organs.

Most often, CMV infection manifests itself as:

• ARVI (acute respiratory viral infection). In this case, patients complain of weakness, general malaise, fatigue, headaches, runny nose, inflammation and enlargement of the salivary glands, with copious amounts of saliva and whitish deposits on the gums and tongue.
• A generalized form of CMV infection with damage to internal (parenchymal) organs. Inflammation of the liver tissue, adrenal glands, spleen, pancreas, and kidneys is observed. This is accompanied by frequent “causeless” pneumonia and bronchitis, which are difficult to respond to antibiotic therapy; There is a decrease in immune status, and the number of platelets in the peripheral blood decreases. Damage to the blood vessels of the eye, intestinal walls, brain and peripheral nerves is common. Enlargement of the parotid and submandibular salivary glands, inflammation of the joints, skin rash.
• Damage to the genitourinary system in men and women is manifested by symptoms of chronic nonspecific inflammation. If the viral nature of the existing pathology is not established, the diseases do not respond well to antibiotic therapy.

Pathology of pregnancy, fetus and newborn are the most serious complications of CMV infection. The maximum risk of developing this pathology occurs when the fetus becomes infected during pregnancy. However, it must be remembered that problems often arise in pregnant women with the activation of a latent infection with the development of viremia (the release of the virus into the blood) with subsequent infection of the fetus. Cytomegalovirus is one of the most common causes of miscarriage.

Intrauterine CMV infection of the fetus leads to the development of severe diseases and damage to the central nervous system (mental retardation, hearing loss). In 20-30% of cases the child dies.

Clinical picture

The duration of the incubation period remains unclear since the initial forms of CMV infection occur latently. Characteristic clinical symptoms develop as a result of exposure to factors that weaken the immune system.

Congenital CMV infection in children in early periods of life also occurs as an asymptomatic carriage. Then it manifests itself in the form of various severe complications, the most common:

• Deafness.
• Chorioretinitis.
• Cytomegalovirus syndrome.

In particularly severe cases, congenital CMV infection leads to secondary pathologies and death in the first weeks of life. You can avoid these consequences by doing a blood test for cytomegalovirus before conceiving a child.

Cytomegalovirus: treatment

With a diagnosis that is confirmed when testing for cytomegalovirus IgG, IgM and DNA is positive, treatment should be comprehensive. First of all, if the test for IgG, IgM and DNA is positive, treatment should be aimed at strengthening the human immune system.

With active manifestations of cytomegalovirus, treatment is also aimed at improving liver function and reducing the symptoms of infection (headache, upset stomach, fever, rash).

If cytomegalovirus is diagnosed, treatment may be required against the background of reduced immunity, as well as as a preventive measure for new exacerbations of the infection.

Acute congenital CMV

It is a consequence of primary infection of the mother during pregnancy. Develops in approximately 5% of children infected with CMV infection in utero. In other cases, it occurs hidden and does not lead to serious consequences. The mortality rate of acute congenital CMV infection is high, accounting for up to 30% of cases. Surviving children often suffer severe consequences, including:

• Delay in physical and mental development.
• Chronic jaundice.
• Hydrocephalus.
• Polycystic pancreas.

If a child is infected in the early stages of embryogenesis, the fetus is highly likely to die. Survivors have serious defects and developmental anomalies:

• Microcephaly.
• Lung hypoplasia.
• Defects in the structure of the kidneys of the heart and aorta.
• Esophageal atresia.
• Chronic congenital CMV

Mortality during the development of this form of infection is low; it is characterized by the development of severe pathologies of the child’s organs and systems. These include: hydro- and microcephaly, lens opacity, deafness, microgyria (underdevelopment of the convolutions of the brain).

Detailed description of the study

Cytomegalovirus (CMV, Latin cytomegalovirus) is a common virus that, according to various sources, infects up to 70% of the world's population. Nearly one in three children has been exposed to this pathogen by age 5, and more than half of adults are exposed to CMV by age 40.

CMV can be isolated from many biological environments of the body during an active infection: from saliva, urine, blood, breast milk, semen, vaginal secretions. The virus is easily transmitted from person to person through direct contact with an infected person or with body fluids containing the infectious agent, including those preserved on objects such as toys or household items.

Although most people become infected with CMV during childhood and young adulthood, few people are aware of it because CMV usually causes no symptoms or only short-term symptoms in healthy people. Individuals with mild cytomegalovirus infection may have nonspecific symptoms, such as:

1. Sore throat;
2. Moderate increase in body temperature;
3. Increased fatigue;
4. Enlarged lymph nodes;
5. Muscle aches;
6. Headache.

In general, the symptoms of the disease sometimes resemble the flu, they usually go away within one to two weeks. However, the virus itself remains in the body for life, without manifesting itself in any way, similar to other viruses from the herpesvirus family.

If the body's immune defenses are weakened, the virus can become active again (reactivate) and cause illness.

CMV can cross the placental barrier and cause severe health problems in infants. Because of this, it is dangerous to become infected with the virus during pregnancy. The majority of newborns infected with CMV, approximately 90%, do not show pathology immediately after birth, but several months later they may experience hearing and vision impairment, neurological and mental disorders. Less commonly, pathology is noted after birth; in such cases, jaundice and an enlarged spleen and liver are observed.

In adults, CMV causes disease due to decreased immunity. This is observed in patients with AIDS, people after organ or bone marrow transplantation, and during chemotherapy in cancer patients. In case of reactivation against the background of decreased immunity, CMV affects many organs and systems: eyes, digestive tract, lungs, brain and others. CMV further suppresses the immune system, facilitating the addition of secondary infections, such as fungal infections of the skin and internal organs.

Testing for CMV detects antibodies in the blood that are produced by the body in response to infection. During initial infection, the body secretes class M antibodies (anti-CMV IgM), which are subsequently replaced by anti-CMV IgG after a few weeks.

The study of AtIgM allows you to diagnose an acute infection and take timely measures to prevent complications of the disease.

Acquired CMV infection

In the majority of infected people, it occurs without a pronounced clinical picture, in the form of a subclinical form or latent virus carriage. The transition to a clinically expressed disease is observed with various disturbances in the functioning of the immune system arising under the influence of various risk factors.

In this case, acute acquired CMV infection develops, the symptoms of which are similar to viral hepatitis or infectious mononucleosis. It can occur secretly and is detected accidentally during a screening blood test for cytomegalovirus.

Another common form of acquired CMV infection is mononucleosis-like syndrome. The clinical manifestations of this form are almost identical to another disease caused by the Epstein-Barr herpesvirus - infectious mononucleosis.

The incubation period can last up to 60 days. The active phase of the disease begins with flu-like symptoms: prolonged fever, chills, severe muscle and joint pain, severe fatigue. Patients often complain of a sore throat, enlarged regional lymph nodes, and skin rashes.

Rarely, symptoms of hepatitis such as jaundice may occur. Blood tests show an increase in liver enzymes (ALAT, AST). Pneumonia may develop, the probability of lung damage is 5-6%.

The duration of the disease can be up to 1-2 months, after which most patients experience a complete recovery. Some symptoms last longer, for example, enlarged lymph nodes can persist for up to six months.

Symptoms of CMV

The content of the article

CMV may be accompanied by the following symptoms:

• chronic weakness;
• temperature rise;
• sore throat, sore throat;
• pain in the right and left hypochondrium;
• enlarged lymph nodes.

Acquired cytomegalovirus infection in newborns

It develops as a result of infection of a newborn during the passage of the birth canal or in the initial stages of life - during breastfeeding, contact with carriers of the virus. Most children are asymptomatically converted to the carrier form.

Clinical symptoms appear in cases of severe prematurity or low birth weight. The infection occurs in the form of long-term pneumonia, often accompanied by bacterial damage to the respiratory system. The development of hepatitis, enlarged lymph nodes, and delays in mental and physical development are possible. During pregnancy, it is necessary to undergo a lot of tests that help identify the presence of not only CMV infection, but also toxoplasmosis.

Generalized form of CMV infection

Develops in infected people with extremely weakened immune systems. It is characterized by serious damage to the liver, nervous system, gastrointestinal tract, and lungs. The severity of the pathology depends on the state of the immune system; especially severe manifestations are observed in those taking immunosuppressants and patients with AIDS.

The main clinical manifestations of generalized CMV infection:

• Subacute onset. It is characterized by: severe loss of strength, fever, increased sweating at night, patients complain of pain in the joints and muscles.
• Ulcers of the stomach, intestines and esophagus manifest themselves in the form of abdominal pain and dyspeptic symptoms. They can lead to internal bleeding and perforations in the walls of the gastrointestinal tract.
• Hepatitis. There is jaundice, tenderness and enlargement of the liver.
• Pneumonia. Chest pain, cough, and respiratory rate increase.
• Encephalitis. Main manifestations: nystagmus (rhythmic twitching of the eyes), drowsiness, damage to one or more pairs of cranial nerves, disorientation. People who are HIV positive may develop AIDS dementia syndrome.
• Retinitis. Leads to complete or partial blindness.
• Multiple organ failure. The most common cause of death in a generalized infectious process. It manifests itself in the form of dysfunction of all organs and systems of the body affected by the virus.

Cytomegalovirus - symptoms of CMV

Congenital form of cytomegalovirus infection

Most children with congenital cytomegalovirus infection never show symptoms or have any health problems. However, some may have health problems that appear at birth or may develop later.

Some children may have the following signs of congenital cytomegalovirus infection at birth:

• problems with the liver, lungs and spleen;
• low birth weight;
• small head size (microcephaly);
• convulsions.

About 1 in 10 babies with CMV will have noticeable signs at birth, such as jaundice or an enlarged liver. They may also have long-term health problems such as hearing and vision loss and developmental delays.

About 40-60% of infants born with signs of congenital cytomegalovirus infection will have long-term health problems, such as:

• mental retardation;
• lack of coordination;
• muscle weakness.

Because signs of cytomegalovirus infection at birth are similar to other medical conditions, the diagnosis should be confirmed by laboratory tests within 2 to 3 weeks after birth.

Acquired form of cytomegalovirus infection

Most healthy people who acquire CMV after birth have an insidious disease and are unaware that they have been infected. In this case, there are no long-term health consequences.

In some cases, cytomegalovirus infection in healthy people can cause the following symptoms:

• fever;
• redness of the throat;
• muscle pain;
• fatigue;
• enlarged lymph nodes.

Once a person becomes infected, the virus establishes a lifelong latency and can recur periodically. Illnesses caused by CMV rarely occur unless a person's immune system is weakened due to therapeutic drugs or illness.

People with weakened immune systems may experience more severe symptoms, affecting the eyes, lungs, liver, esophagus, stomach and intestines.

Mononucleosis-like syndrome

People with normal immunity who become ill with cytomegalovirus infection may experience a syndrome similar to mononucleosis. In this case, lymphomonocytosis is observed in the blood with the appearance of atypical mononuclear cells. The symptoms resemble a cold:

• high body temperature and chills (up to 1 month);
• headache, aches in muscles and joints;
• fatigue, malaise and weakness;
• enlargement of the salivary and lymph glands;
• skin rash resembling rubella rash.

In some cases, with mononucleosis-like syndrome, hepatitis develops - jaundice and an increase in liver enzymes in the blood. In 6% of cases, pneumonia develops as a complication.

Mononucleosis syndrome lasts for 6-90 days. After this, complete recovery occurs. Residual effects may persist for a month (enlarged lymph nodes, weakness, malaise).

Symptoms of cytomegalovirus in men and women

In men, CMV can affect the prostate and testicles. In women, the inner layer of the uterus, ovaries, cervix and vagina.

Symptoms of chronic cytomegalovirus infection

If CMV remains in the body for a long time, the immune system loses the ability to resist it. In this case, there is a prolonged increase in body temperature to 37.1-38.0 degrees. There is an enlargement of lymph nodes of different groups and an enlargement of the liver or spleen (rarely). Myocarditis (inflammation of the muscle tissue of the heart) also develops, and eye damage occurs.

Cytomegalovirus infection in people with normal immunity

It is not characterized by significant deviations, so a person’s life activity remains unchanged. The body's protective functions independently cope with CMV.

Cytomegalovirus infection in AIDS

An extremely severe course of the disease is noted. It is possible that a generalized form of infection may develop, in which damage to internal organs is observed:

• brain (dementia, encephalitis, meningitis);
• lungs (pneumonia, pneumonitis);
• kidneys (renal failure, nephritis with necrosis);
• eye (retinitis, complete blindness).

Damage to the liver (hepatitis), heart, adrenal glands, spleen, intestines, esophagus, etc. is less common. The prognosis in most cases is unfavorable.

Cytomegalovirus during pregnancy

If primary infection with cytomagalovirus occurs in pregnant women, they may experience the following complications:

• premature birth;
• spontaneous miscarriage;
• polyhydramnios;
• frozen pregnancy;
• intrauterine infection of the fetus, severe damage to its nervous system;
• fetal death.

Particularly severe consequences occur when the fetus is infected in the 1st trimester of pregnancy. In the case of pregnancy against the background of a pre-existing cytomegalovirus infection, in the chronic course of this pathology, when there are already protective antibodies in the woman’s blood, the probability of infection of the fetus does not exceed 10%. That is why, even at the stage of planning conception, it is necessary to be examined for the presence of TORCH infection (toxoplasmosis, rubella, cytomegalovirus, herpes, other infections).

If intrauterine infection of the fetus occurs, the risk of death of newborns is high. Survivors are often diagnosed with serious abnormalities:

• lack of vision and/or hearing;
• microcephaly;
• brain calcification;
• impaired growth and formation of the musculoskeletal system;
• hepato- and splenomegaly;
• pneumonia;
• frequent hemorrhages in parenchymal and hollow organs;
• delayed mental and physical development;
• heart diseases.

Cytomegalovirus infection during pregnancy is, of course, an alarming and dangerous factor. However, this is not a verdict. You need to see a doctor and follow medical recommendations, minimizing the risk of possible complications.

• The use of antiviral drugs in 80% of cases helps to stop the exacerbation - the virus and antibodies indicating its activity (IgM) disappear from the blood of patients.
• The use of human immunoglobulin for the treatment of the manifest form of CMV in pregnant women stops the reproduction of the virus and its elimination from the body in 75% of cases.

Classification and stages of development of cytomegalovirus infection

Acquired CMV can be latent or manifest. In the first case, we are talking about the absence of clinical signs. Diagnosis can only be made by laboratory tests. The manifest form of cytomegalovirus can be localized - sialoadenitis, and generalized - damage to the stomach and intestines, development of hepatitis, etc. In the congenital form, acute (death is often inevitable when a newborn is infected) and chronic course of the disease is possible. Cytomegalovirus infection is isolated separately in HIV-infected people.

According to the severity of CMV, there are:

• mild – there is no obvious damage to internal organs and no change in function;
• moderate - dysfunction of internal organs is moderate, no critical changes are observed;
• severe - damage to internal organs is pronounced (catastrophic functional failures are observed and complications develop).

Diagnosis of infection

In a routine blood test, patients suffering from CMV infection observe:

• Severe lymphocytosis.
• Atypical mononuclear cells (up to 10% or more).
• The total number of white blood cells rarely falls outside the normal range. In newborns, thrombocytopenia and a decrease in the number of red blood cells may be detected. In a biochemical blood test, an increase in the activity of liver enzymes is observed.

In samples of cerebrospinal fluid from patients with central nervous system damage, an increase in protein components, neutrophilic pleocytosis and a significant decrease in glucose levels are detected.

Treatment

It is based on conducting serological blood tests for cytomegalovirus - antibodies specific to this infection are detected. These include:

• Immunoglobulin M. These are markers of an acute infectious process during primary infection or the development of an exacerbation. They go beyond normal limits only 1-2 months after the virus enters the body. Increased rates can persist for up to six months. A high IgM titer in pregnant women means that there is a risk of infection of the embryo.
• Immunoglobulin G. An unimportant type of immunoglobulin. It rises quite late, during the period of attenuation of the infectious process. Serves to detect cytomegalovirus in the body.
• PCR. Allows you to accurately identify the genetic material of the virus in blood, other biological fluids, and tissues. Its variety, quantitative PCR, makes it possible to monitor the activity of the development of the infectious process as it provides data on the magnitude of virion reproduction.
• Direct microscopy. Based on direct observation of infected cells with a specific morphology. Materials obtained from biopsy, urine sediment, saliva, and blood are suitable for analysis. They are distinguished by their enormous size, large intranuclear inclusion, which is surrounded by a light rim, this is the so-called “owl's eye”. Microscopy is the simplest and most accessible method for detecting CMV infection.

When the test for cytomegalovirus IgG, IgM and DNA is positive: transcript

Testing for IgG, IgM antibodies to cytomegalovirus and its DNA in adults is the most reliable way to identify the infection and start treatment on time.

It is especially important to determine infection in pregnant women. If the test result for cytomegalovirus IgG is positive, the risk of intrauterine infection cannot be excluded. Its likelihood is higher if IgG antibodies to cytomegalovirus are detected together with IgM, and also if the IgG concentration exceeds the reference values, which range from 0 to 6 U/ml.

If the cytomegalovirus IgG test result is positive, contact with the virus is confirmed. If the test for cytomegalovirus IgG is positive together with IgM, then we can think about an acute period of infection. If the test for cytomegalovirus IgG is positive, and IgM is positive in a titer of 1:200 or more, the likelihood of a recent primary infection is very high.

A negative result for both antibodies allows one to exclude infection or suspect a seronegative version of it, and may also indicate severe immune suppression.

Prevention

Subclinical forms of CMV infection and latent carriage are extremely common, and therefore in most cases do not require specific treatment, even if specific antibodies are detected. Treatment of such forms of cytomegalovirus is aimed at strengthening the body's defenses with the help of immunomodulators and preventing risk factors that lead to exacerbation of the disease.

To treat clinically active forms of CMV infection, 3 drugs are used that are quite effective:

• Ganciclovir. Administered by intravenous infusion twice a day. The course of treatment lasts 2-3 weeks. It is especially effective in combination with Citotect, a specific immunoglobulin, which is also administered intravenously.
• Foscarnet. Used if treatment with ganciclovir was not effective enough. It is administered intravenously three times a day, by slow administration (infusion duration is at least 2 hours).
• Cidofovir. Another drug of choice for CMV infection, which is used for resistance to ganciclovir. Administered intravenously, 1 time per week.

These drugs are contraindicated for use by pregnant women. In this case, pathogenetic therapy is prescribed. It includes a variety of interferon preparations (viferon, roferon) as well as inducers of the production of their own interferons - cycloferon, neovir.

The administration of interferons and other immunomodulatory drugs occurs under the control of the immunological status. If immunomodulators are ineffective, it is possible to prescribe a course of human immunoglobulin, which is administered by intramuscular injection in an amount of 3 to 5 with an interval of 2-3 days.

Various forms of CMV infection can masquerade as diseases with similar symptoms. Therefore, differential diagnosis is required with:

• Sepsis.
• Infectious mononucleosis.
• Bacterial meningitis.

CVM diagnostic methods

• Polymerase chain reaction (PCR). PCR is used to diagnose the presence of CMV in the blood, cerebrospinal fluid, urine and amniotic fluid. This is a popular tool for detecting cytomegalovirus, but its results are not always correct (a false positive result is possible).
• Virological method
  . With its help, the CMV virus is isolated from the blood, urine, amniotic fluid and cerebrospinal fluid. The study involves inoculating the patient’s biological material on a special nutrient medium, where the virus multiplies. The main disadvantage of this method is its duration (2 or more weeks).
• Diagnostics of antibodies to CMV in the blood
  . The most popular analysis allows you to determine the fact of CMV infection and how long ago the infection spread. If cytomegalovirus has recently appeared in the patient’s blood, the transcript of the analysis will show the presence of IgM antibodies. IgG immunoglobulins will be diagnosed if the infection is long-standing.

Analysis for cytomegalovirus: indications

Pregnant women are required to be tested for CMV, since infection with the virus in the first 5 months of pregnancy can result in fetal death. Lack of treatment for CMV infection in the second half of pregnancy is also dangerous. In addition, a cytomegalovirus test must be performed in the following cases:

• pregnancy planning;
• signs of fetal infection, placental insufficiency;
• symptoms of infectious mononucleosis;
• enlargement of the spleen and liver of unknown origin;
• miscarriage, miscarriage;
• pneumonia in a child with an uncharacteristic course.

Analysis for CVM is included in the examination for the TORCH complex during pregnancy.

Specific diagnostics

The main direction in the prevention of CMV is compliance with the rules of personal hygiene, individual protection when in contact with patients with cytomegalovirus. It is especially important to follow preventive recommendations for people at risk:

• Patients who have undergone transplantation.
• Pregnant women.
• HIV-infected.
• Patients suffering from immunodeficiencies.

Means for specific prevention are under development. The only drug that allows prophylaxis in patients after transplantation is letermovir. It has not yet found widespread use; it is recommended for use only in the USA.

Cytomegalovirus, IgG

IgG antibodies to cytomegalovirus are specific immunoglobulins produced in the human body during the period of pronounced clinical manifestations of cytomegalovirus infection and are a serological marker of this disease, as well as a past cytomegalovirus infection.

Synonyms Russian

IgG antibodies to cytomegalovirus (CMV).

English synonyms

Anti-CMV-IgG, CMV Antibody, IgG.

Research method

Solid-phase chemiluminescent enzyme-linked immunosorbent assay (“sandwich” method).

Units

U/ml (unit per milliliter).

What biomaterial can be used for research?

Venous, capillary blood.

How to properly prepare for research?

Do not smoke for 30 minutes before donating blood.

General information about the study

Cytomegalovirus (CMV) belongs to the herpes virus family. Just like other representatives of this group, it can persist in a person throughout his life. In healthy people with normal immunity, the primary infection occurs without complications (and is often asymptomatic). However, cytomegalovirus is dangerous during pregnancy (for the child) and during immunodeficiency.

Cytomegalovirus can be infected through various biological fluids: saliva, urine, semen, blood. In addition, it is transmitted from mother to child (during pregnancy, childbirth or breastfeeding).

As a rule, cytomegalovirus infection is asymptomatic. Sometimes the disease resembles infectious mononucleosis: the temperature rises, the throat hurts, and the lymph nodes become enlarged. In the future, the virus remains inside the cells in an inactive state, but if the body is weakened, it will begin to multiply again.

It is important for a woman to know whether she has been infected with CMV in the past because this is what determines whether she is at risk for pregnancy complications. If she has already been infected before, then the risk is minimal. During pregnancy, an old infection may worsen, but this form usually does not cause serious consequences.

If a woman has not yet had CMV, then she is at risk and should pay special attention to CMV prevention. It is the infection that the mother contracted for the first time during pregnancy that is dangerous for the child.

During a primary infection in a pregnant woman, the virus often enters the child’s body. This does not mean that he will get sick. As a rule, CMV infection is asymptomatic. However, in approximately 10% of cases it leads to congenital pathologies: microcephaly, cerebral calcification, rash and enlargement of the spleen and liver. This is often accompanied by a decrease in intelligence and deafness, and even death is possible.

Thus, it is important for the expectant mother to know whether she has been infected with CMV in the past. If so, then the risk of complications due to possible CMV becomes negligible. If not, you need to take special care during pregnancy:

• avoid unprotected sex,
• do not come into contact with another person’s saliva (do not kiss, do not share dishes, toothbrushes, etc.),
• observe the rules of hygiene when playing with children (wash your hands if saliva or urine gets on them),
• get tested for CMV if there are signs of general malaise.

In addition, cytomegalovirus is dangerous if the immune system is weakened (for example, due to immunosuppressants or HIV). In AIDS, CMV is severe and is a common cause of death in patients.

The main symptoms of cytomegalovirus infection:

• inflammation of the retina (which can lead to blindness),
• colitis (inflammation of the colon),
• esophagitis (inflammation of the esophagus),
• neurological disorders (encephalitis, etc.).

The production of antibodies is one way to fight a viral infection. There are several classes of antibodies (IgG, IgM, IgA, etc.).

Antibodies of class G (IgG) are present in the blood in the greatest quantities (compared to other types of immunoglobulins). During primary infection, their levels increase in the first weeks after infection and then can remain high for years.

In addition to quantity, IgG avidity is often determined - the strength with which the antibody binds to the antigen. The higher the avidity, the stronger and faster the antibodies bind viral proteins. When a person is first infected with CMV, his IgG antibodies have low avidity, then (after three months) it becomes high. IgG avidity indicates how long ago the initial CMV infection occurred.

What is the research used for?

• To determine whether a person has been infected with CMV in the past.
• For the diagnosis of cytomegalovirus infection.
• To identify the causative agent of a disease that is similar to cytomegalovirus infection.

When is the study scheduled?

• During pregnancy (or when planning it) - to assess the risk of complications (screening study), with symptoms of cytomegalovirus infection, with abnormalities in the fetus according to ultrasound results.
• For symptoms of cytomegalovirus infection in people with weakened immune systems.
• For symptoms of mononucleosis (if tests do not detect Epstein-Barr virus).

What do the results mean?

Reference values: 0 - 0.5 U/ml.

Negative pregnancy result

• The woman has not been infected with CMV before - there is a risk of acquiring a primary CMV infection. However, if no more than 2-3 weeks have passed since infection, then IgG may not have appeared yet. To exclude this option, you need to take the test again after 2 weeks.

Positive result before pregnancy

• The woman has already been infected with CMV in the past - the risk of complications is minimal.

Positive result during pregnancy

• It is impossible to draw a clear conclusion. It is possible that CMV entered the body before pregnancy. But it is possible that the woman became infected recently, at the beginning of pregnancy (several weeks before the test). This option poses a danger to the child. For an accurate diagnosis, the results of other tests are needed (see table).

When trying to identify the causative agent of an unknown disease, a single IgG test provides little information. The results of all tests must be taken into account.

Test results in different situations

Important Notes

• Sometimes you need to find out whether the newborn child himself is infected with cytomegalovirus. However, the IgG test in this case is not informative. IgG can penetrate the placental barrier, so if the mother has antibodies, they will also be present in the child.
• What is reinfection? In nature, there are several varieties of CMV, so it is possible that a person already infected with one type of virus becomes infected again with another.

Also recommended

• Cytomegalovirus, IgM
• Cytomegalovirus, immediate early protein IEA, antibodies
• Cytomegalovirus, DNA [real-time PCR]

Who orders the study?

General practitioner, therapist, infectious disease specialist, gynecologist.

Literature

• Adler SP Screening for cytomegalovirus during Pregnancy. Infect Dis Obstet Gynecol. 2011:1-9.
• Goldman's Cecil Medicine. 24th ed. Goldman L, Schafer AI, eds. Saunders Elsevier; 2011.
• Lazzarotto T. et al. Why is cytomegalovirus the most frequent cause of congenital infection? Expert Rev Anti Infect Ther. 2011; 9(10): 841-843.

Examination for cytomegalovirus infection at Medart

The laboratory of the Medart clinic is equipped with modern high-precision equipment that allows you to perform any type of diagnosis of cytomegalovirus infection and other types of serological diagnosis of infectious diseases (diagnosis for HIV, syphilis, hepatitis, giardiasis, Helicobacter pylory, toxoplasmosis).

A blood test for cytomegalovirus is included in a set of tests for STIs (sexually transmitted infections). It is also possible to diagnose CMV infection based on individual indicators, for example, when planning pregnancy.

If necessary, test results can be obtained on the day the material is submitted. This is especially important in severe forms of CMV infection, when the speed of diagnosis and effective treatment is critical. Advantages of the clinic:

• Ability to perform a full range of diagnostic procedures.
• Optimal pricing policy.
• Qualified specialists.

Patients of the Medart clinic receive a full range of medical services - from preliminary consultation and laboratory diagnosis of cytomegalovirus to the prescription of effective therapy and receiving recommendations for prevention and rehabilitation after the disease.

Antibodies to cytomegalovirus IgG, CMV IgG quantity.

Antibodies to cytomegalovirus IgG, CMV IgG quantitative

- allows you to determine the presence of IgG antibodies to cytomegalovirus (CMV or CMV), which indicates a current or recent infection. The duration of the incubation period ranges from 15 days to 3 months. With this infection, non-sterile immunity occurs (that is, complete elimination of the virus is not observed). Immunity to cytomegalovirus infection (CMVI) is unstable and slow. Reinfection with an exogenous virus or reactivation of a latent infection is possible. Due to long-term persistence in the body, the virus affects all parts of the patient’s immune system. When a person comes into contact with CMV, his immune system exhibits a protective response by producing IgM and IgG antibodies against CMV.

IgG antibodies to cytomegalovirus are specific immunoglobulins that are produced in the human body during the period of pronounced clinical manifestations of cytomegalovirus infection and indicate current or recent infection.

Cytomegalovirus infection

is a widespread viral infection of the body, which belongs to the so-called opportunistic infections, which usually occur latently. Clinical manifestations are observed against the background of physiological immunodeficiency states (children in the first 3–5 years of life, pregnant women - more often in the 2nd and 3rd trimester), as well as in persons with congenital or acquired immunodeficiencies (HIV infection, use of immunosuppressants, oncohematological diseases, radiation, diabetes and so on.).

Cytomegalovirus

- is part of the herpes virus family. Like other representatives of this group, it can persist in a person throughout his life. The risk group includes children 5–6 years old, adults 16–30 years old, as well as people who practice anal sex. Children are susceptible to airborne transmission from parents and other children with latent forms of infection. For adults, sexual transmission is more common. The virus is found in semen and other body fluids. Vertical transmission of infection (from mother to fetus) occurs transplacentally and during childbirth.

In healthy people with normal immunity, the primary infection occurs without complications (and is often asymptomatic). In rare cases, a picture of infectious mononucleosis develops (about 10% of all cases of infectious mononucleosis), clinically indistinguishable from mononucleosis caused by the Epstein-Barr virus. Replication of the virus occurs in the tissues of the reticuloendothelial system, epithelium of the urogenital tract, liver, mucous membrane of the respiratory tract and digestive tract. When immunity is reduced after organ transplantation, immunosuppressive therapy, HIV infection, as well as in newborns, CMV poses a serious threat, since the disease can affect any organ. The development of hepatitis, pneumonia, esophagitis, gastritis, colitis, retinitis, diffuse encephalopathy, fever, leukopenia is possible. The disease can be fatal.

Cytomegalovirus in immunodeficiency states

Cytomegalovirus is dangerous in cases of immunodeficiency and during pregnancy is potentially dangerous for the development of the fetus. Therefore, 5-6 months before a planned pregnancy, it is necessary to undergo a TORCH examination in order to assess the state of immunity in relation to these viruses, if necessary, carry out treatment, or provide prevention and control.

When a pregnant woman is initially infected with cytomegalovirus (in 35–50% of cases) or the infection is reactivated during pregnancy (in 8–10% of cases), an intrauterine infection develops. Confirming or excluding the fact of recent infection is especially important when examining pregnant women, since it is with primary infection during pregnancy that the risk of vertical transmission of infection and the development of fetal pathology is high.

If an intrauterine infection develops before 10 weeks, there is a risk of developmental defects and possible spontaneous termination of pregnancy. When infected at 11–28 weeks, intrauterine growth retardation and hypo- or dysplasia of internal organs occur. If infection occurs at a later date, the lesion may be generalized, affecting a specific organ (for example, fetal hepatitis) or appear after birth (hypertensive-hydrocephalic syndrome, hearing impairment, interstitial pneumonia, etc.). Manifestations of infection also depend on maternal immunity, virulence and localization of the virus.

To date, a vaccine against cytomegalovirus has not been developed. Drug therapy allows you to increase the period of remission and influence the recurrence of infection, but does not eliminate the virus from the body.

It is impossible to completely cure this disease: cytomegalovirus cannot be removed from the body. But if you promptly, at the slightest suspicion of infection with this virus, consult a doctor and carry out the necessary tests, then you can keep the infection in a “dormant” state for many years. This will ensure a normal pregnancy and the birth of a healthy child.

Laboratory diagnosis of cytomegalovirus infection is of particular importance in the following categories of subjects:

Women preparing for pregnancy

1. Latent course of the disease 2. Difficulty in differential diagnosis of primary infection and recurrent infection during examination during pregnancy 3. Severe consequences of intrauterine infection in newborns

Pregnant women

1. Severe consequences of intrauterine infection in newborns 2. Immunodeficiency states (generalized forms)

Consecutive repeated determination of the level of IgG antibodies in newborns makes it possible to distinguish congenital infection (constant level) from neonatal infection (increasing titers). If the titer of IgG antibodies does not increase during repeated (after two weeks) analysis, then there is no reason for alarm; if the titer of IgG increases, the issue of abortion should be considered.

CMV and TORCH

CMV infection is part of the group of TORCH infections (the name is formed by the initial letters of the Latin names - Toxoplasma, Rubella, Cytomegalovirus, Herpes), which are considered potentially dangerous for the development of a child. Ideally, a woman should consult a doctor and undergo laboratory testing for TORCH infection 2–3 months before a planned pregnancy, since in this case it will be possible to take appropriate therapeutic or preventive measures, and, if necessary, compare the results of studies before pregnancy in the future with the results of examinations during pregnancy.

Indications:

• preparation for pregnancy;
• signs of intrauterine infection, feto-placental insufficiency;
• state of immunosuppression due to HIV infection, neoplastic diseases, taking cytostatic drugs, etc.;
• clinical picture of infectious mononucleosis in the absence of infection caused by the Epstein-Barr virus;
• hepato-splenomegaly of unknown nature;
• fever of unknown etiology;
• increased levels of liver transaminases, gamma-GT, alkaline phosphatase in the absence of markers of viral hepatitis;
• atypical course of pneumonia in children;
• miscarriage (frozen pregnancy, recurrent miscarriages).

Preparation
It is recommended to donate blood in the morning, between 8 am and 12 pm. Blood is drawn on an empty stomach, after 4–6 hours of fasting. It is allowed to drink water without gas and sugar. On the eve of the examination, food overload should be avoided.

Interpretation of results

Units of measurement: UE*

A positive result will be accompanied by an additional comment indicating the sample positivity rate (SP*):

• CP >= 11.0 – positive;
• CP <= 9.0 – negative;
• CP 9.0–11.0 is doubtful.

Exceeding reference values:

• CMV infection;
• intrauterine infection is possible, the likelihood of its occurrence is unknown.

Within reference values:

• No CMV infection was detected;
• infection occurred within the previous 3–4 weeks;
• intrauterine infection is impossible (except in the presence of IgM).

“Doubtful
” is a borderline value that does not allow reliably (with a probability of more than 95%) to classify the result as “Positive” or “Negative”. It should be borne in mind that such a result is possible with a very low level of antibodies, which can occur, in particular, in the initial period of the disease. Depending on the clinical situation, repeat testing of antibody levels after 10–14 days may be useful to assess changes.

*Positivity rate (PR) is the ratio of the optical density of a patient's sample to the threshold value. CP - positivity coefficient, is a universal indicator used in enzyme immunoassays. CP characterizes the degree of positivity of the test sample and can be useful to the doctor for the correct interpretation of the result obtained. Since the positivity rate does not correlate linearly with the concentration of antibodies in the sample, it is not recommended to use CP for dynamic monitoring of patients, including monitoring the effectiveness of treatment.