Active generation and selection for HIV intersubtype A/D recombinant forms in a coinfected patient in Kenya.

To investigate the in vivo evolution of recombinant HIV, we followed up on a mother who was initially coinfected with subtypes A and D in Kenya. Blood samples were obtained in 1996 and 2002, and HIV pol and env genes were amplified by PCR, cloned, sequenced, and phylogenetically analyzed. As for the 1996 sample most of the clones generated from the pol and env genes clustered either with subtypes A and D reference strains. However, two clones from the pol gene were found to be independent recombinants between subtypes A and D by RIP analysis, suggesting active generation of recombinant forms. As for the 2002 sample, all the clones from the pol gene clustered only with the subtype A reference strain, while all the env clones clustered only with subtype D, denoting a dominance of an A/D recombinant form. These results indicate that in patients dually infected with subtypes A and D there is an ongoing generation and selection for A/D recombinant forms.