Clinical, virologic, and immunologic correlates of HIV-1 intraclade B dual infection among men who have sex with men.

OBJECTIVE: To investigate the susceptibilities to and consequences of HIV-1 dual infection.
DESIGN: We compared clinical, virologic, and immunologic factors between participants who were dually infected with HIV-1 subtype B and monoinfected controls who were matched by ongoing HIV risk factor.
METHODS: The viral load and CD4 progressions of dually and singly infected participant groups were compared with linear mixed-effects models, and individual dynamics before and after superinfection were assessed with a structural change test (Chow test). Recombination breakpoint analysis (GARD), HLA frequency analysis, and cytotoxic T-lymphocyte (CTL) epitope mapping were also performed (HIV LANL Database).
RESULTS: The viral loads of dually infected participants increased more over 3 years of follow-up than the viral loads of monoinfected controls, whereas CD4 progressions of the two groups did not differ. Viral escape from CTL responses following superinfection was observed in two participants whose superinfecting strain completely replaced the initial strain. This pattern was not seen among participants whose superinfecting virus persisted in a recombinant form with the initial virus or was only detected transiently. Several HLA types were over-represented in dually infected participants as compared to monoinfected controls.
CONCLUSIONS: These results identify potential factors for dual infection susceptibility and further define its clinical consequences.