810 Genetic Evidence of Vertical Transmission of Kaposiís Sarcoma-associated Herpesvirus (Human Herpesvirus 8) in Zambian Families O. Yegorov*1, T. M'soka1,2, J. Muyanga2, C. Kankasa2, G. Bhat2, T. Kapakala2, C. Chintu2, C. Mitchell3, J. T. West1, C. Wood1 1Univ of Nebraska, Lincoln; 2Univ Teaching Hosp, Lusaka, Zambia; and 3Univ of Miami, FL
Background: We previously documented transmission of HHV-8 in mother/infant pairs from endemic regions using serological techniques. In this study, we show direct evidence of HHV-8 transmission from mother to child using DNA sequencing, heteroduplex mobility assay (HMA), and phylogenetic analyses of the variable regions in the HHV-8 K1 gene.
Methods: Children who presented with mucocutaneous or lymphadenopathic Kaposiís sarcoma lesions at the Univ Teaching Hosp, Lusaka, Zambia, were selected as index cases. In addition, family members of the index cases who tested positive for HHV-8 by immunofluorescence assay were recruited into the study. DNA was extracted from the peripheral blood mononuclear cells (PBMC) and the variable region of the K1 gene (approx 700 bp) was amplified by nested PCR. For each individual, nested PCR products were analyzed by HMA, with 10 or more clones analyzed by DNA sequencing. The sequences were aligned using standard programs and phylogenetic relationships determined using the neighbor-joining method.
Results: The K1 variable region clones from 10 index cases and 4 associated family mothers were analyzed. HMA specific for variable regions in the K1 gene was developed to identify and distinguish variations among strains. HMA showed a distinct distribution in sequences based on the hypervariable K1 gene clones for each individual. In 4 mother/infant pairs, similar intra-pair distributions of heteroduplex bands were observed for both participants. Sequence analysis of the clones used for HMA revealed considerable differences (5-40 mismatches); however, all cognate mother/infant K1 sequences were more closely related to one another than to any other HHV-8 sequences obtained from unrelated individuals.
Conclusions: Our study is the first to show that analysis of the K1 gene sequence variation can provide direct evidence of HHV-8 transmission from mother-to-child.