CHANGES IN PLASMA AMINO-ACID-CONCENTRATIONS IN RESPONSE TO HIV-1

Plasma concentrations of 21 amino acids were determined for 20 control subjects and 20 subjects infected with human immunodeficiency virus t ype 1 (HIV). Compared with the control subjects, the HIV-infected grou p had lower cystine, tryptophan, and methionine (decreased 67%, 52%, a nd 32%, respectively, P <0.001 for each) and increased taurine (230%, P <0.001) and lysine concentrations (30%, P <0.001). Other amino acid concentrations changed modestly. Amounts of cystine, tryptophan, methi onine, taurine, and lysine did not differ significantly between subgro ups of HIV-infected subjects with >200 (n = 6) or <200 (n = 14) CD4(+) lymphocytes per microliter, suggesting that the concentrations decrea se soon after infection and change little thereafter. Activation of me tabolism of cystine to taurine may explain reciprocal changes in these amino acids and known depletion of cystine and glutathione. The selec tive changes in amino acid profiles observed during HIV infection diff er from those recognized for malnutrition or other pathological proces ses.