HIV Infection, HCV Coinfection, and Alcohol Use: Associations with Microbial Translocation and Immune Activation.

BACKGROUND: Human immunodeficiency virus (HIV) infection and heavy drinking independently promote microbial translocation and inflammation. However, it is not known how alcohol use may affect these processes in people living with HIV (PLWH). This study tested the hypothesis that alcohol exacerbates innate immune dysfunction in PLWH. METHODS: Participants were 75 PLWH and 34 uninfected controls. Groups were recruited to have similar proportions of nondrinkers, moderate drinkers, and heavy drinkers. Substance use data and plasma samples were collected at up to 3 visits over a 5-year study period. Recent alcohol use was assessed with the Timeline Followback Interview. Biomarkers of microbial translocation (lipopolysaccharide, LPS) and immune activation (lipopolysaccharide binding protein, LBP; soluble CD14, sCD14; soluble CD163, sCD163) were quantified using enzyme-linked immunosorbent assays. Analyses tested 2 hypotheses: (i) that biomarker levels would be significantly higher in PLWH than controls with comparable alcohol use and (ii) that current alcohol use would exacerbate biomarker elevations in PLWH. The second analysis included the interaction of alcohol use with hepatitis C virus (HCV) coinfection. RESULTS: Groups were matched on alcohol use, smoking, and other drug use. All biomarkers were significantly higher in PLWH relative to controls (LBP: p = 0.005; LPS: p = 0.014; sCD14: p < 0.001; sCD163: p < 0.001). In PLWH, alcohol use showed a significant, positive association with sCD163, but not with other biomarkers. However, the interaction of alcohol use with HCV coinfection was significant for all biomarkers (LBP: p = 0.002; LPS: p = 0.026; sCD14: p = 0.0004; sCD163: p = 0.001). In pairwise tests with sequential Bonferroni correction, HIV/HCV coinfected individuals who drank heavily had significantly higher sCD163 compared to coinfected nondrinkers and to HIV monoinfected nondrinkers, moderate drinkers, and heavy drinkers (ps < 0.005). Coinfected moderate drinkers had significantly higher sCD163 than each monoinfected group (ps < 0.003). In addition, sCD14 was significantly higher in coinfected moderate drinkers than coinfected nondrinkers (p = 0.027). CONCLUSIONS: As predicted, PLWH had higher levels of LBP, LPS, sCD14, and sCD163 than uninfected individuals with similar alcohol use. In PLWH, alcohol by itself was significantly associated only with higher sCD163. However, heavy or moderate alcohol use was associated with elevations in macrophage activation (sCD163) and monocyte activation (sCD14) in HIV/HCV coinfected individuals.