DIRECT COMPARISON OF THE RELATIONSHIP BETWEEN CLINICAL OUTCOME AND CHANGE IN CD4(-POSITIVE HOMOSEXUAL MEN AND INJECTING DRUG-USERS() LYMPHOCYTES IN HUMAN IMMUNODEFICIENCY VIRUS)

Background and Methods: To compare rates of decline of CD4(+) lymphocy tes among human immunodeficiency virus-positivelymphocytes among human immunodeficiency virus-positive homosexual men and injecting drug use rs, we followed up prevalent human immunodeficiency virus-positive hom osexual men and current or former injecting drug users from February 1 988 through August 1991. Subjects were free of acquired immunodeficien cy syndrome at study entry and had semiannual clinical and laboratory evaluation, including measurement of T-cell subsets, under common prot ocols. Initial levels and rates of change of CD4(+) lymphocyte counts were compared according to cohort membership and clinical progression, defined by the development of thrush or an acquired immunodeficiency syndrome-defining illness. Median follow-up was 30 months for both coh orts. Results: At study entry, homosexual men had lower absolute numbe rs of circulating CD4(-) lymphocytes than did injecting drug users (45 9/mu L [0.46X10(9)/L] vs 509/ mu L, respectively). During follow-up, h omosexual men exhibited a faster decline in CD4(+) lymphocyte Counts a s well as more frequent development of HIV-related symptoms (thrush or acquired immunodeficiency syndrome). In both cohorts, initial levels of CD4(+) lymphocytes and rates of decline in these cells were strongl y associated with progression of disease, defined as remaining asympto matic, onset of thrush, or onset of acquired immunodeficiency syndrome . Once homosexual men and injecting drug users were stratified by dise ase progression, their initial levels and rates of decline of CD4(+) l ymphocyte counts were similar. Thus, crude differences between the two study groups largely resulted from differences in development of clin ical symptoms. Conclusions: In these cohorts of homosexual men and inj ecting drug users, clinical outcome was much more important than risk group membership in determining changes in CD4(+) lymphocyte numbers. The close similarity between the groups also suggests that drug use, e thnicity, and socioeconomic status play a minor role in the progressio n of human immunodeficiency virus infection.