Human Immunodeficiency Virus type 1 in seronegative infants born to HIV-1-infected mothers

BACKGROUND: Some individuals repeatedly exposed to Human Immunodeficiency Virus do not seroconvert and are resistant to HIV infection. Here, in a pediatric cohort of HIV seronegative infants born of HIV-infected mothers, we have studied eight non-breastfed children in whom viral DNA was detected in their PBMC. Our objective was to assess whether silent infection in these children can be explained by the presence of integrated viral DNA. METHODS: The presence of viral DNA was corroborated by nested PCR with primers for gag and the nef/LTR regions of HIV-1. Integration of HIV DNA into the host genome was assessed by an Alu-LTR PCR. Amplicons were sequenced and phylogenetic analyzes were done. RESULTS: HIV-1 DNA was detected in the earliest available PBMC sample from all eight infants, and two of them tested positive for HIV DNA at 2 years of age. Nested PCR resulted in the amplification of gag, nef/LTR and Alu-LTR fragments, which demostrated that HIV-1 DNA was integrated in the host cell genome. Each individual has a characteristic sequence pattern and is different from the LTR sequence of HXB2 prototype virus and other Mexican isolates. CONCLUSION: HIV-1 DNA was observed in PBMC from HIV exposed seronegative children in this pediatric cohort.