Clinical and immunological correlates of immune-complex-dissociated HIV-1 p24 antigen in HIV-1-infected children.

It has been reported that HIV-1 p24 antigen (p24 Ag) detection is improved after dissociation of immune complexes using acid treatment (ICD assay). In order to evaluate the clinical significance of p24 Ag detected by the standard assay and by the ICD assay in pediatric patients, we related these measurements to clinical status, level of p24 antibody, and percentage of CD4+ lymphocytes. Fifty-nine plasma specimens from 20 symptomatic HIV-1-infected children, collected prospectively over a 1-year period, were tested for these markers. Plasma was collected at the beginning of zidovudine therapy and approximately 7 and 12 months thereafter. Compared with the standard assay, the ICD assay showed a higher number of samples positive for p24 Ag (78% versus 34%) and an increase in the levels of p24 Ag (median value of 129 versus 24 pg/ml). The anti-p24 antibody level was inversely correlated with the p24 Ag level measured by either assay. Four children negative for p24 Ag by both assays had a stable clinical course. In contrast, 50% of the children negative by the standard assay but positive for ICD p24 Ag and 75% of the children positive by both assays had progression of disease. No patients were positive by the standard assay but negative by the ICD assay. Children whose plasma tested positive by both assays had lower percentages of lymphocytes that were CD4+ by comparison with children who were negative by both assays; children whose plasma tested positive only by the ICD assay formed an intermediate group.(ABSTRACT TRUNCATED AT 250 WORDS)