['Initial investigations demonstrated a deficiency of glutathione (GSH) in the epithelial lining fluid (ELF) of HIV-seropositive patients. In a recent study, our laboratory was unable to document such a deficiency. The current study was performed in an attempt to reconcile those disparate findings.', 'To determine if ELF GSH decreases over time in asymptomatic HIV-seropositive subjects.', 'Prospective, longitudinal study.', 'Major university medical center.', 'Thirty-three asymptomatic HIV-seropositive volunteers.', 'None.', 'BAL was performed on 33 asymptomatic HIV-seropositive subjects at baseline, 6 months later, and 12 months later. The volume of ELF and the concentration of GSH and oxidized GSH were determined. The concentration of total GSH in ELF was 689.0+/-100.4 microM. This significantly decreased when measured 6 and 12 months later (355.9+/-41.7 microM, and 397.9+/-52.7 microM, respectively, p=0.01, compared with baseline, both comparisons). Significant decreases were also noted in the HIV-seropositive subjects who smoked cigarettes (baseline--762.6+/-142.4 microM; 6 months--373.7+/-45.9 microM; 12 months--459.3+/-73.8 microM, p<0.03, for baseline vs 6 months, and baseline vs 12 months). In nonsmoking HIV-seropositive subjects, there was a decrease in ELF GSH over time, but it did not reach statistical significance (baseline--589.1+/-138.2 microM; 6 months--335.3+/-74.1 microM; 12 months--345.8+/-74.0 microM, p>0.1, all comparisons). The percentage of total GSH in the oxidized form was similar at all three time points (baseline--3.8+/-0.5%; 6 months--3.1+/-0.5%; 12 months--3.9+/-0.9%, p>0.1, all comparisons).'] Does alveolar fluid glutathione decrease in asymptomatic HIV-seropositive subjects over time?