EFFECT OF GLUTATHIONE DEPLETION AND ORAL N-ACETYL-CYSTEINE TREATMENT ON CD4(+) AND CD8(+) CELLS

HIV-infected individuals and SIV-infected rhesus macaques have, on the average, decreased plasma cysteine and cystine concentrations and dec reased intracellular glutathione levels. We show that the cysteine sup ply and the intracellular glutathione levels have a strong influence o n the T cell system. A study of healthy human subjects revealed that p ersons with intracellular glutathione levels of 20-30 nmol/mg protein had significantly higher numbers of CD4(+) T cells than persons with e ither lower or higher glutathione levels. Persons who moved during a 4 -week observation period from the optimal to the suboptimal range (10- 20 nmol/mg) experienced, on the average, a 30% decrease in CD4(+) T ce ll numbers. This decrease was prevented by treatment with N-acetyl-cys teine (NAC). NAC caused this relative increase of CD4(+) T cell number s in spite of decreasing glutathione levels and not by increasing the glutathione level. Our studies suggest that the immune system may be e xquisitely sensitive not only against a cysteine and glutathione defic iency but also against an excess of cysteine.