ABSTRACT
HIV-infected persons were found to have, on average, abnormally low intracellular glutathione levels (1,2), low plasma cystine levels (3,4), and low plasma glutathione levels (5). At face value, the low glutathione and cysteine levels suggested the possibility that HIV-infected patients might suffer from various manifestations of oxidative damage due to an insufficient antioxidative defense. At the time, it was a quite common belief that oxidative processes in biological systems are generally disadvantageous, and antioxidants accordingly beneficial. In the meantime, it has become widely appreciated (i) that oxidative processes play, among other roles, an important positive role in the regulation of signal transduction and gene expression in the immune system, and (ii) that the cysteine supply and intracellular glutathione level determine not only the capacity of one of the most powerful antioxidant defense systems but also the level of glutathione disulfide (GSSG), an important biological oxidant with regulatory function. It is, therefore, not appropriate simply to equate a glutathione and cysteine deficiency with an insufficient antioxidant defense system.
