PERIPHERAL HUMAN T-LYMPHOCYTE MAINTENANCE OF IMMUNE FUNCTIONAL-CAPACITY AND PHENOTYPIC CHARACTERISTICS FOLLOWING IN-VIVO COCAINE EXPOSURE

The effects of cocaine exposure upon the host's immune response is equ ivocal since a variety of studies have generated conflicting conclusio ns, often as the result of differences between in vitro and/or animal models and the actual conditions experienced in humans who are acutely abusing this drug. To further address this issue, we have studied a g roup of patients who were positive for cocaine or cocaine metabolites and we evaluated a variety of functional parameters of T-lymphocytes a nd other peripheral lymphoid cell populations, as well as immunophenot ypic characteristics of these cells. When compared to normal controls and patients who were negative for cocaine, we found that the cocaine- positive patients had T-cell functional assays which were essentially normal, with the exception of a slight depression in PHA stimulation L ikewise, the immunophenotype of the peripheral blood lymphocytic popul ations showed normal percentages and numbers of their T cell subsets ( CD4, CD8), NK cells, and B cells. Multicolor flow cytometry analysis r evealed no difference in T cell subpopulations positive for the ''memo ry'' marker, CD62L, No correlation could be established between levels of cocaine or cocaine metabolites and any phenotypic, demographic, or functional parameter, In summary, these results demonstrate that indi viduals acutely exposed to cocaine do not show markedly altered T cell function or fluctuations in phenotypically identified cell population s. These studies imply that acute cocaine exposure does not predispose individuals to grossly apparent immunosuppression. However, the possi bility that subtle, transient, or more specific changes in the immune system may be incurred by use of cocaine, particularly with chronic ex posure, remains to be determined. (C) 1998 Academic Press.