Comparative epidemiological and immunological characteristics of patients with HIV/HCV coinfection among injection drug users, and patients without drug history in Tatarstan

High prevalence of HIV/HCV coinfection among injection drug users (IDUs) in the Republic of Tatarstan requires studies on the influence of behavioral factors on immunopathology. Objective of our study was to conduct a comparative analysis of immunological parameters in IDUs with HIV/HCV coinfection and those without a history of drug use. This single-center comparative study included 38 patients with HIV/HCV coinfection who used injection drugs and 36 patients with HIV/HCV without a history of drug use. The sample size was calculated to achieve 80% power at a significance level of p < 0.05. Lymphocyte subpopulation profiles and circulating immune complex levels were assessed. In the IDU group, a more pronounced decrease in the level of CD4-lymphocytes (26.2±0.7% vs 30.1±0.8%; p < 0.001) and the absolute number of CD4 + cells (0.43±0.04 vs 0.61±0.04×10 9 /L, p < 0.01) was revealed. The immunoregulatory index was significantly lower in the IDU group (0.60±0.02 vs. 0.75±0.02, p < 0.001). The level of circulating immune complexes (CIC) was significantly higher in the IDU group (568.3±30.5 vs 402.3±28.0 arb.units, p < 0.001). In cases with clinical stage III of HIV infection, IDUs demonstrated the greatest reduction in absolute lymphocyte count (24.1±0.9% vs. 31.3±1.6% in stage II patients, p < 0.001). The injection drug usage is an independent factor exacerbating immune dysfunction in HIV/HCV co-infection. These findings support the need to develop differentiated approaches to monitoring and management of this cohort.