MULTIPLE EFFECTS ON PERIPHERAL HEMATOLOGY FOLLOWING ADMINISTRATION OFRECOMBINANT HUMAN INTERLEUKIN-12 TO NONHUMAN-PRIMATES

Interleukin 12 has demonstrated a wide spectrum of bioactivity on T an d NK cells both in vitro and in vivo. Therapeutic potential of these a ctivities has been suggested by studies in murine tumor, viral and mod els of disease. We have investigated the in vivo effect of rhlL-12 in cynomolgus monkeys treated with 1 mu g/kg/day by bolus i.v or s.c. inj ection for 5 days. Treated groups had transient decreases in total WBC counts as compared to controls, with reversable decreases seen mainly in the lymphocyte and monocyte subsets. Phenotypic analysis showed a decrease in the number of CD4(+) and CD8(+) cells/mu L on Days 2 and 4 . Reversible thrombocytopenia and anemia were noted in both treated gr oups as compared to controls. Plasma neopterin concentrations were inc reased in both treated groups as compared to controls. These data show that rhll-12 has multiple effects on peripheral hematology and sugges ts that this model may be useful to investigate in vivo bioactivity of rhlL-12. (C) 1994 Academic Press, Inc.