TUBERCULIN AND ANERGY TESTING IN HIV-SEROPOSITIVE AND HIV-SERONEGATIVE PERSONS

Objective: To determine the prevalence and predictors of reactivity to tuberculin purified protein derivative (PPD) and skin test anergy in patients with human immunodeficiency virus (HIV) infection and in HIV- seronegative controls. Design: Cross-sectional analysis of baseline da ta from a prospective, multicenter study of pulmonary complications of HIV infection. Setting: Community-based cohort of persons with and wi thout HIV infection. Patients: A total of 1171 HIV-seropositive patien ts without AIDS (841 homosexual men, 274 intravenous drug users, and 5 6 women with heterosexually acquired infection); 182 HIV-seronegative persons (125 homosexual men and 57 intravenous drug users). Measuremen ts: Delayed-type hypersensitivity response to tuberculin PPD, trichoph ytin, mumps, and Candida antigens; T-lymphocyte subsets. Results: The prevalence of tuberculin PPD reactivity was higher among intravenous d rug users than among homosexual men, in both HIV-seronegative (19.1% c ompared with 6.8%, P = 0.03) and HIV-seropositive persons (15.1% compa red with 2.5%, P < 0.001). Among HIV-infected patients, the prevalence of tuberculin reactivity varied directly and that of anergy inversely with the absolute CD4 lymphocyte count. Prevalences were 1% and 72%, respectively, in patients with fewer than 200 CD4 cells/mm3, and 8.4% and 25.5%, respectively, in those with 600 CD4 cells/mm3 (P < 0.001 fo r both comparisons). Patients with HIV infection and fewer than 400 CD 4 lymphocytes/mm3 had a lower prevalence of PPD reactivity than HIV-se ronegative controls (2.7% compared with 10.0%, P < 0.001). The stronge st predictors of tuberculin reactivity were intravenous drug use, blac k race, a previous positive PPD test result, and a history of Calmette -Guerin bacillus vaccination. The strongest predictor of anergy was HI V seropositivity. Conclusions: The response to delayed-type hypersensi tivity antigens depends on immune status. The value of PPD and anergy testing in HIV-seropositive patients depends on the ability of such te sting to predict subsequent tuberculosis, which is imprecisely known. Until more data or better methods are available, these tests should be done as early as possible in the course of HIV infection.