Abstract

HIV-infected infants may have CXCR4-using (X4-tropic) HIV, CCR5-using (R5-tropic) HIV, or a mixture of R5-tropic and X4-tropic HIV (dual/mixed, DM HIV). The level of infectivity for R5 virus (R5-RLU) varies among HIVinfected infants. HIV tropism and R5-RLU were measured in samples from HIV-infected Ugandan infants using a commercial assay. DM HIV was detected in 7/72 (9.7%) infants at the time of HIV diagnosis (birth or 6-8 weeks of age, 4/15 (26.7%) with subtype D, 3/57 (5.3 %) with other subtypes, P=0.013). A transition from R5-tropic to DM HIV was observed in only two (6.7%) of 30 infants over 6-12 months. Six (85.7%) of seven infants with DM HIV died, compared to 21/67 (31.3%) infants with R5-tropic HIV (p=0.09). Higher R5-RLU at 6-8 weeks was not associated with decreased survival. Infants with in utero infection had a higher median R5-RLU than infants who were HIV-uninfected at birth (p=0.025).

Keywords: CCR5, CXCR4, HIV-1, infant, survival, transmission, tropism, HIV, Ugandan Infants, HIV-infected infants, CXCR4-using (X4-tropic) HIV, CCR5-using (R5-tropic) HIV, R5-tropic, X4-tropic HIV, R5 virus, R5-RLU, CD4, T cell-tropic virus, chronic HIV infection, dual-tropic HIV, AIDS, single dose nevirapine, sdNVP, pMTCT), HIVNET, HIV Tropism, retroviral vector, HEK 293 cells, pseudoviruses, U87 cells, HIV pol subtype, Wilcoxon rank test, Fisher's exact test), human immunodeficiency virus type 1-infected mothers, V3 regions, HIV-1 subtypes