Value Of Determination Of Specific IgG Antibody's Avidity Index In The Diagnostic Of Human Cytomegalovirus Primary Infection

Objective:To evaluate human cytomegalovivrus(HCMV)specific IgG avidity index(AI) on distinguishing primary HCMV infection from non-primary infection(secondary infection, reinfection or persistent infection) in pregnant women,so as to provide an effective detection method to reduce birth defects born with severe congenital HCMV infection and reduce the damage to fetuses and relative costs caused by invasive diagnosis in the early time.Methods:The blood samples of pregnant women out-patient and in-patient were selected randomly,then detected their human cytomegalovirus IgG,IgM antibodies and divided into four groups:past infection,secondary infection or re-infection,suspicious primary infection and primary infection.The measurement of HCMV-IgG AI was performed by standard indirect ELISA method.using 35.0mmol/L diethylamine as the mild protein denaturing agent,then measure enery hole OD values in the microplate reader using 450nm.Tracked pregnant women to give birth and detected HCMV-IgM of umbilical cord blood whose mother had human cytomegalovirus infection by ELISA method.at last,compared fetal infection between primary infection and non-primary infection in pregnant women.Results:Of the 2450 samples,1858 were from women with past HCMV infection,97 from those with secondary infection or re-infection,76 samples were suspicious primary infection and 86 samples were primary infection.When the HCMV-IgG AI less than 40%as critical value in diagnosing HCMV primary infection,the sensitivity was 78.6%,the specificity was 98.7%,YI index is 77.3%,The mean AI in the samples from women with past infection,secondary infection or re-infection,suspicious primary infection and primary infection was(69.54±12.78)%, (71.55±10.98)%,(68.87±15.74)%,(39.49±25.97)%respectively.There was a statistical difference between the primary and non-primary HCMV infection(P＜0.01).In the samples of neonate whose mother had primary infection,there were 7 samples HCMV-IgM was positive and the infection rate was 50%.While in the neonate samples of non-primary infection.there were 3 samples HCMV-IgM was positive,the infection rate was 0.9%.Conclusion:1:The procedures of using 35.0mmol/L diethylamine solution and washed once for 10 mins was considered suitable for determination HCMV-IgG Al;2:At present,the combination of HCMV-IgG AI and HCMV-IgM assay seems to be one of the best serological test for differentiating primary from non-primary HCMV infection.3:The damagement to neonatal of primary infection was more stronger than other styles.