The effect of latent Mycobacterium tuberculosis infection on human immunodeficiency virus (HIV) disease progression and HIV RNA load among injecting drug users

To examine the relationship between latent Mycobacterium tuberculosis infection and human immunodeficiency virus (HIV) disease progression, two studies were done among a cohort of HIV-infected injecting drug users. First, the decline in CD4 cell count after baseline tuberculin skin testing was prospectively compared for 37 tuberculin-positive (induration ≤5 mm) and 284 tuberculin-negative (induration ≤2 mm) persons. After adjustment for baseline immune function, the mean 6-month CD4 cell decline was not significantly different (34.5 vs. 45.6 cells, respectively, P = .14). Second, the plasma HIV burden at baseline skin testing was compared for 33 tuberculin-positive cases and 33 matched tuberculin-negative controls. HIV RNA was detected in 8 cases and 10 controls (odds ratio = 0.67, 95% confidence interval = 0.19-2.36). Among the 14 pairs with HIV detected in ≤1 member, the HIV concentration was higher for the case in 4 and for the control in 10 (P = .18). These findings suggest that unlike active tuberculosis, latent M. tuberculosis infection does not hasten HIV progression.