EARLY DIAGNOSIS OF VERTICAL HIV-INFECTION IN INFANTS BY RAPID DETECTION OF IMMUNE COMPLEX-DISSOCIATED HIV P24 ANTIGEN

Conventional HIV antibody detection was problematic for diagnosis of H IV infection in young infants <18 months of age who were born to HIV-i nfected mothers. The HIV p24 antigen (Ag) is mainly bound to the antib ody as an immune complex which causes underdetection by conventional m ethods. Attempts were made to dissociate these immune complexes to rel ease free p24 Ag for detection. The current study's objective was to e valuate the rapid assays for detection of immune complex-dissociated p 24 Ag (ICD p24 Ag) for early identification of HIV-infected infants as compared to the detection of HIV RNA by polymerase chain reaction (PC R) assay. The ICD was performed by acid dissociation and heat-denature d dissociation, and then the released ICD p24 Ag were detected. Tested were 41 HIV-infected children who acquired the infection perinatally and who had positive PCR and 30 HIV noninfected children with negative PCR The overall sensitivity of the ICD p24 Ag detection after acid-an d heat-denatured dissociation in the infected children was 85.4% and 8 7.8%, respectively, compared to 34.2% of p24 Ag without pretreatment f or dissociation of the serum samples. The specificity of nonimmune com plex dissociation and both methods of immune complex dissociation test were 100%. The sensitivity of ICD-p24 Ag test using these two methods showed excellent agreement (K = 0.893). Besides the relatively high s ensitivity and specificity of the ICD p24 Ag test, its advantages incl ude simplicity, rapidity, and relatively low cost-indicating ICD p24 A g detection as a promising method for early diagnosis of vertical HIV infection in infants.