Immune complex-dissociated p24 antigenemia in the diagnosis of human immunodeficiency virus infection in vertically infected Brazilian children.

ABSTRACT

PIP A retrospective cohort study evaluated the presence of immune complex-dissociated (ICD) p24 antigen in frozen plasma samples of 40 children born to HIV-seropositive mothers and followed in the outpatient clinic of Gaffree-Guinle University Hospital. ICD has been helpful in the early diagnosis of infants born of HIV-seropositive mothers within the first 2 months of life. After testing all charts were reviewed for evidence of HIV-related clinical findings and determination of HIV serology until the child reached 24 months of age. The children were all born to HIV-infected Brazilian women between 1984 and 1992. 17 boys (mean age at first evaluation for HIV infection, 17.3 months) and 23 girls (mean age at first evaluation, 16.8 months) were included. Of the 17 boys, 9 were Caucasian and 8 were African-Brazilian; 11 girls were Caucasian and 12 were African-Brazilian. An immune complex disruption procedure was performed at the Universidade do Rio de Janeiro on 100-mcl aliquots of serial plasma samples from the 40 patients enrolled. 200 mcl of treated plasma were then assayed for the presence of p24 antigen through a quantitative enzyme immunoassay. 21 of 40 (52%) infants were identified as HIV-infected through persistent HIV seropositivity after 18 months of age. ICD p24 antigen was detected in at least 1 plasma specimen from 15 of 21 (71.4%) of HIV-infected children, whereas p24 antigen was present in 11 of 21 (52.4%) children infected with HIV. The sensitivity of ICD p24 antigen in diagnosing HIV infection in this cohort of children was 71.4%, whereas that of p24 antigen was 52.4%. The highest mean titers of HIV ICD p24 antigen were observed between 7 and 12 months of life. A history of breast-feeding was present in 18 of 21 (86%) of the HIV-infected infants and in only 5 of 19 (26%) of the uninfected children (p 0.001). In 21 HIV-infected children, 12 (57%) were asymptomatic and 9 (43%) were symptomatic at the time the first ICD p24 antigen test was obtained.^ieng