Progressive cellular immune impairment leading to development of AIDS: Two-year prospective study of HIV infection in drug addicts

We have studied immunological, serological and clinical abnormalities in 264 HIV-positive and HIV-negative drug abusers. Ninety percent of the 264 drug addicts (mean age 26 ± 0.8 years) were found to have HIV antibodies and there was a significant increase (P < 0.01) in the frequency of HIV antibody positivity with increasing duration of exposure to parenteral drug abuse. There was a very strong correlation between the progressive decline of the mean T4⁺ helper/inducer cells and T4⁺/T8⁺ ratio, the low response to pokeweed mitogen and the more severe clinical manifestations of HIV infection. Impairment of delayed-type hypersensitivity to recall antigens was only seen in group IV as defined by the Center for Disease Control. Within group IV, anergy was found to be highly associated (83%) in patients with opportunistic infections. All other HIV-positive addicts from groups II and III, as well as HIV-negative addicts had normal in vivo responses to test antigens. We have also analysed in a prospective follow-up lasting 6-24 months, the evolution of HIV infection in a cohort of 50 HIV-antibody-positive drug addicts. Thirty-two percent showed clinical progression and most of the drug addicts that proceeded to full-blown AIDS developed anergy (82%) prior to clinical deterioration with development of opportunistic infections. We conclude, that in seropositive drug addicts a low absolute count of helper/inducer cells (mean ± s.e. = 243 ± 48 cells/mm³), a low response to pokeweed mitogen and anergy are predictive markers of progression to AIDS.