Alcohol use and T-lymphocyte subsets among injection drug users with HIV-1 infection: a prospective analysis

Alcohol use is known to alter immune function and has immunosuppressive effects that may modify T-lymphocyte subpopulations. However, there is no clear evidence regarding the relationship of alcohol use with the progression of immunodeficiency in human immunodeficiency virus-type 1 (HIV-1)-seropositive individuals, particularly injection drug users (IDUs).

Using prospective data from a cohort of IDUs in a study of the natural history of HIV infection, we examined the relationship of alcohol use and changes in T-lymphocyte subsets. Among the 2921 IDUs followed semiannually in outpatient clinics, 188 were documented HIV-1 seroconverters with known time of seroconversion. At each visit, all study participants were interviewed, underwent physical examinations, and had blood drawn for laboratory studies. Alcohol use was measured by reported frequency and quantity of alcoholic beverages. Longitudinal analyses included data for up to 5 years postseroconversion. To formally test the association of alcohol use with change in levels of CD4+ and CD8+ cells subsequent to HIV seroconversion, regression models incorporating autocorrelation structure were applied.

Alcohol use was not appreciably related to age, gender, marital status, income, education, or the duration of intravenous drug use. CD4% decreased for all IDUs within the first 5 years after seroconversion, with no significant differences between alcohol categories. CD8% increased for all IDUs, with no significant differences by alcohol category within the first 2 years after seroconversion. However, between 2 to 5 years postseroconversion, there was a statistically significant increase among the heaviest drinkers: CD8% increased 6.9%/year [95% confidence interval (CI): 4.7, 8.0] for the IDUs who reported > 21 drinks/week, 2.4%/year (95% CI: 0.8, 4.0) for IDUs who drank 21 drinks/week or less, and 0.4% (95% CI: -2.1, 2.9) for abstainers. Similar results were obtained for CD4 and CD8 absolute counts.

In this study population of IDUs, CD8% (but not CD4%) is associated with alcohol consumption early after HIV seroconversion. This is the first prospective study to date to assess the relationship of alcohol use with HIV progression from the time of HIV seroconversion among a cohort of IDUs. If confirmed in future investigations, the findings may have significant implications for prevention and early intervention programs aimed at inhibiting disease progression among HIV-positive IDUs.