Serologic, immunologic, and clinical features of parenteral drug users from contrasting populations

We screened inpatient and outpatient parenteral drug users with no clinical evidence of AIDS for immunodeficiency and antibodies to HTLV-III by ELISA. Among 20 outpatient drug users, 5 (25%) were seropositive. Three of these (and 2 who were seronegative) had low T-cell ratios. Over 6 months, 1 seropositive patient with a low ratio developed oral thrush and weight loss. We also studied 13 parenteral drug users hospitalized for conditions other than AIDS. Eight had low T-cell ratios, and at least 6 of these developed AIDS or ARC within 4 months. Serum from 8 of 13 inpatients was available for HTLV-III testing: 6/8 were seropositive and 3 of these 6 were among those developing AIDS or ARC. Abnormal T-cell ratios among all patients were associated with abnormal HTLV-III serology (p = .02). Of the 7 patients who developed AIDS or ARC, 4 were tested for both antibodies and T-cell ratios: all 4 were seropositive and had low ratios. A low ratio (p = .0004), a positive ELISA (p = .014), and abnormalities of both tests (p = .001) were associated with the development of AIDS or ARC. Of the 26 patients without AIDS or ARC, 3 were lost to follow-up and 23 did not develop AIDS or ARC. Six of these 26 had abnormal ratios. Of the 21 patients who did not develop AIDS or ARC and who were tested for HTLV antibodies, 2 were lost to follow-up. Seven of 21 were seropositive and 2/21 were both seropositive and had a low ratio. One of these 2 seropositive patients with low ratios also had lymphadenopathy, but he was lost to follow-up. The other had no adenopathy and remained well until her death from trauma a year later. This study found two populations with very different risks. Six of 13 hospitalized parenteral drug users and only 1 of 20 healthy outpatients developed AIDS or ARC.