Phenotypic and functional assessments of immune status in the rat spleen following acute heroin treatment

Heroin use is associated with an increased incidence of several types of in fections, including HIV. Yet few studies have assessed whether heroin produ ces pharmacological alterations of immune status: that might contribute to the increased rate of infections amongst heroin users. The present study in vestigated whether a single administration of heroin to rats produces dose- dependent alterations in functional measures of immune status and in the di stribution of leukocyte subsets in the spleen. The results showed that hero in produces a dose-dependent, naltrexone-reversible suppression of the conc anavalin A-stimulated proliferation of T cells, Lipopolysaccharide-stimulat ed proliferation of B cells, production of interferon-gamma and cytotoxicit y of natural killer (NK) cells in the spleen. Heroin's suppressive effect o n NK cell activity results in part from a heroin-induced decrease in the re lative number of NKR-P1A(hi)CD3(-) NK cells in the spleen. Heroin also decr eases the percent of a splenic granulocyte subset, the CD11b/c(+)HIS48(hi) cells, whose function currently is unknown. In contrast, heroin does not al ter relative numbers of CD4(_)CD3(+) T cells, CD8(+)CD3(+) T cells, CD45(+) B cells, NKR-P1A(lo)CD3(+) T cells, CD11b/c(+)ED1(+) (or CD11b/c(+)HIS48(- )) monocytes/macrophages or CD11b/c(+)ED1(-) (or CD11b/c(+)HIS48(+)) total granulocytes in the spleen. Collectively, these findings demonstrate that h eroin produces pharmacological effects on functional and phenotypic measure s of immune status. (C) 2000 Elsevier Science B.V. All rights reserved.