Effect of antiretroviral agents on T-lymphocyte subset counts in healthy HIV-negative individuals

To study the effect of antiretroviral agents on T-lymphocyte counts in HIV-negative individuals, total counts and CD4⁺ and CD8⁺ lymphocyte counts were measured in health care workers (HCW) who had been occupationally exposed to HIV who were untreated (164 HCW, group A), or had received antiretroviral postexposure prophylaxis (PEP). PEP included zidovudine (150 HCW, group B), zidovudine plus lamivudine (48 HCW, group C), or zidovudine, lamivudine, and indinavir (85 HCW, group D), at standard dosage for a mean of 30, 27, and 27 days of treatment, respectively. Lymphocyte values were collected after a mean of 44 days following exposure in group A, 48 days in group B, and 30 days both in groups C and D. Student's t-, nonparametric Mann-Whitney, and Kruskal-Wallis tests were used for statistical analysis. A slight increase in mean CD4 (range, 4.8%-6.7%) and CD8 (range, 1.4%-9.3%) cells/mm³ was observed in each group. Gender, PEP duration, side effects, and follow-up time did not correlate with responses. Data did not vary using CD4 and CD8 percentages. These findings seem to reject any direct effects of antiretroviral agents, independent of retroviral inhibition, on proliferation and redistribution of T lymphocytes, as well as the hypothesized braking of lymphocyte apoptosis. The observed variations could reflect biologic variability.