Abstract
OBJECTIVE: The aim of this study was to characterize the demographic, behavioural, clinical and immunogenetic determinants of HIV-1 superinfection in a high-risk cohort of MSM. DESIGN: A retrospective cohort study of prospectively followed MSM. METHODS: Ninety-eight MSM with acute or early HIV-1 monoinfection were followed for a median of 15.6 months. Demographic and human leukocyte antigen (HLA) genotype data were collected at enrolment. Sexual behaviour, clinical and the infection status (monoinfection or superinfection) data were recorded at each visit (at enrolment and thereafter at a median of 4.2-month intervals). HIV-1 superinfection risk was determined by Cox regression and Kaplan-Meier survival analysis. RESULTS: Ten individuals (10.2%) had superinfection during follow-up. Cox regression did not show significantly increased superinfection risk for individuals with an increased amount of condomless anal intercourse, lower CD4 T-cell count or higher viral load, but higher number of sexual contacts demonstrated a trend towards significance [hazard ratio, 4.74; 95% confidence interval (95% CI), 0.87-25.97; P = 0.073]. HLA-A*29 (hazard ratio, 4.10; 95% CI, 0.88-14.76; P = 0.069), HLA-B*35 (hazard ratio, 4.64; 95% CI, 1.33-18.17; P = 0.017), HLA-C*04 (hazard ratio, 5.30; 95% CI, 1.51-20.77; P = 0.010), HLA-C*16 (hazard ratio, 4.05; 95% CI, 0.87-14.62; P = 0.071), HLA-DRB1*07 (hazard ratio, 3.29; 95% CI, 0.94-12.90; P = 0.062) and HLA-DRB1*08 (hazard ratio, 15.37; 95% CI, 2.11-79.80; P = 0.011) were associated with an increased risk of superinfection at α = 0.10, whereas HLA-DRB1*11 was associated with decreased superinfection risk (hazard ratio, 0.13; 95% CI, 0.00-1.03; P = 0.054). CONCLUSION: HLA genes may, in part, elucidate the genetic basis of differential superinfection risk, and provide important information for the development of efficient prevention and treatment strategies of HIV-1 superinfection.