PLASMA VIREMIA AND VIRUS PHENOTYPE ARE CORRELATES OF DISEASE PROGRESSION IN VERTICALLY HUMAN-IMMUNODEFICIENCY-VIRUS TYPE 1-INFECTED CHILDREN

Objective. To analyze the relationships among HIV-1 plasma viremia, ph enotype and CD4 T cell counts in vertically infected children. Methods . Plasma viremia was quantified in 37 vertically infected children at different stages of the disease by a standardized molecular assay. Vir us isolation and non-syncytia-inducing or syncytia-inducing (SI) HIV-1 phenotype evaluation were performed in parallel. Results. HIV-1 RNA g enomes were found to be significantly different in CDC clinical classe s N, A, B and C (P = 0.0135) and in immunologic classes 1, 2 and 3 (P = 0.0110). None of the children in Class N or A harbored HIV-1 isolate s with SI phenotype, whereas SI primary isolates were detected in 2 of 7 (29%) and 7 of 10 (70%) Class B and C children, respectively. Simil arly SI variants were present in only 9 of 13 children in immunologic Class 3 (70%), When stratified according to the increasing severity of virologic status, the children showed a significant difference (P = 0 .0458) in viral burden. Conclusions. Clinical symptoms, the most drama tic being reduction in the number of CD4 lymphocytes, and the highest plasma viremia levels were observed in the children in whom fast repli cating, highly cytopathic SI variants were isolated, These data extend the virologic characterization of vertically HIV-1-infected children and suggest that both the plasma viremia levels and phenotype of prima ry isolates are viral correlates of disease progression in vertically infected children.