Avidity of IgG antibodies to herpes simplex virus types 1 and 2

Infection caused by the herpes simplex virus (HSV) is included in the group of reproductively significant infections designated as the TORCH complex (the name is formed by initial letters in Latin names - Toxoplasma, Rubella, Cytomegalovirus, Herpes); primary infection with these pathogens, or exacerbation of an already existing chronic infection from this group during pregnancy is potentially dangerous for fetal and child development. If possible, it is advisable to undergo an examination for TORCH infections 2-3 months before the planned pregnancy in order to have an idea of the state of immunity in relation to them, if necessary, to carry out treatment or provide prevention and control. The TORCH-complex examination is included in the plan for the examination of women during pregnancy. Confirmation or exclusion of the fact of a recent primary infection is especially important when examining pregnant women, since it is with acute primary infection during pregnancy that the risk of vertical transmission of infection and the development of fetal pathology is high. The use of IgG antibody avidity as an indicator of the duration of primary infection has now been introduced into the practice of serological studies for TORCH infections. Avidity (Latin - avidity) is a characteristic of the bond strength of specific antibodies with the corresponding antigens (determined by the number of binding sites and binding strength). During the body's immune response to the penetration of an infectious agent, the stimulated clone of lymphocytes begins to produce specific IgM antibodies first, and later specific IgG antibodies. IgG antibodies have initially low avidity. Then, the development of the immune process gradually (it can be weeks or months) goes towards the synthesis of highly visible IgG antibodies by lymphocytes, which bind more firmly to the corresponding antigens and, accordingly, eliminate them more reliably. The high avidity of specific IgG antibodies makes it possible to exclude a recent primary infection. The determination of the IgG avidity index for herpes simplex virus type 1 and type 2 makes it possible to clarify the timing of infection and differentiate primary herpes infection from exacerbation of chronic or latent infection.

No special training is required. It is recommended to take blood no earlier than 4 hours after the last meal.