THE EFFECT OF DIDEOXYCYTIDINE ON LYMPHOCYTE SUBPOPULATIONS IN NONHUMAN-PRIMATES

In the present study, 2',3'-dideoxycytidine (ddC), which has antiretro viral activity, was given chronically to uninfected nonhuman primates to determine whether it produces adverse immunological or hematologica l effects. Nine healthy adult male rhesus monkeys were divided into th ree groups and given the following doses of ddC in a gelatin vehicle: group A, 0.06, 6.0, 3.0, and 1.5 mg/kg; group B, 0.6 mg/kg; group C, 0 mg/kg. Blood samples were collected for hematologic analysis and flow cytometric analyses of lymphocyte subpopulations. Chronic ddC exposur e did not cause significant changes in the number of red blood cells, monocytes, or reticulocytes. The number of white blood cells and neutr ophils increased and these changes were observed only in group A anima ls at the 1.5 mg/kg dose. The most significant alterations observed we re decreases in the number of T helper cells (CD4) and B cells (CD20). CD4(+) and CD20(+) lymphocytes exhibited dose-related shifts that wer e reversible over time and after drug withdrawal. The results indicate that ddC has few hematologic effects but it does have profound but tr ansient effects on the number of cells in lymphocyte subpopulations in normal primates. (C) 1994 Society of Toxicology.