Rubella: IgM and IgG antibodies to rubella virus in blood

IgM antibodies to rubella virus are normally absent in the blood serum. For IgG antibodies, values greater than 35 IU/ml are considered diagnostically significant.

Rubella (rubeola) is an acute infectious anthroponosis disease transmitted by airborne droplets. Rubella is caused by a virus belonging to the Togaviridae family, Rubivirus genus. Virions contain RNA. Rubella is characterized by winter-spring seasonality of incidence. In 30-50% of infected people, rubella is asymptomatic.

15-50% of women are at risk of contracting rubella during pregnancy. The greatest danger to the offspring is the presence of latent and latent rubella in pregnant women, accompanied by persistence of the pathogen. Infection of the fetus with the rubella virus, depending on the gestational age, causes various malformations. If a woman is infected in the first 2 months of pregnancy, the fetus develops heart defects (patent ductus arteriosus, stenosis of the pulmonary artery and its branches, defects of the interatrial or interventricular septum, etc.), damage to the organ of vision (cataract, glaucoma, retinopathy). Infection of a woman in the 3rd-4th month of pregnancy leads to the formation of defects of the central nervous system (microcephaly, paralysis of the limbs, mental retardation) and damage to the organ of hearing (deafness, defects of the organ of Corti). The earlier the infection of a pregnant woman occurs, the higher the probability of damage to the fetus and the wider the range of possible developmental abnormalities. If a woman becomes ill in the first 6 weeks of pregnancy, the frequency of congenital abnormalities in the newborn is 56%, and if infected in the 13th-16th week of pregnancy, it is 6-10%. After the 16th week of pregnancy, the virus usually does not affect the fetus.

An accurate diagnosis of rubella in children can only be established by isolating and identifying the virus or based on changes in specific antibody titers. ELISA is used for serological diagnostics.

Rubella is diagnosed using the ELISA method, which allows for the detection of specific IgM and IgG antibodies. The dynamics of antibody detection using the ELISA method corresponds to the results of the RTGA. IgM antibodies to the rubella virus appear in the acute period of infection: on the first day of the rash - in 50% of patients, after 5 days - in more than 90%, after 11-25 days - in all patients. The presence of specific IgM antibodies indicates a recent rubella infection (within 2 months). Six weeks after the rash, IgM antibodies are detected in 50% of patients, but in some cases they can persist for up to 1 year. In congenital infection, IgM antibodies are detected immediately after birth, they persist for up to 6 months in 90-97% of newborns. False positive results of the study of IgM antibodies can be obtained in patients infected with parvovirus B19.

Detection of IgM antibodies to rubella virus is used to diagnose the acute period of rubella. After vaccination, IgM antibodies are detected after 15-25 days in 60-80% of cases. During reinfection, the content of IgM antibodies to rubella virus does not increase (it is necessary to study the dynamics of IgG antibodies - a 4-fold increase in titer in paired sera confirms the diagnosis). Low concentrations of IgM antibodies to rubella virus can be detected in infectious mononucleosis and other viral infections (for example, cytomegalovirus infection, measles, herpes infection).

IgG antibodies to rubella virus are detected 3 days after the rash appears in 50% of patients, after 8 days - in more than 90%, on the 15th-25th day - in almost all patients. IgG antibodies persist in those who have recovered from the disease for up to 10 years or more. Determination of the IgG antibody titer to rubella virus is also used to assess the intensity of post-vaccination immunity (they appear on the 25th-50th day after vaccination) and to determine the infection in the anamnesis. The absence of IgG antibodies to rubella virus in newborns excludes congenital infection.

When assessing vaccination, its effectiveness is indicated by the ELISA values: the content of IgG antibodies to the rubella virus is higher than 15 IU/l.

[ 1 ], [ 2 ], [ 3 ]