ELEVATED PLASMA-CONCENTRATION OF REDUCED HOMOCYSTEINE IN PATIENTS WITH HUMAN-IMMUNODEFICIENCY-VIRUS INFECTION

Oxidative stress has been suggested to be an important factor in the i mmunopathogenesis of human immunodeficiency virus (HIV) infection. Red uced plasma thiols may lead to production of reactive oxygen species, thus contributing to the oxidative stress. We quantified the total, re duced, and protein-bound forms of the thiols homocysteine, cysteine, c ysteinylglycine, and methionine in plasma from 21 HIV-infected patient s and 15 healthy control subjects and compared the results with clinic al and immunologic indexes. The HIV-infected patients had significantl y higher concentrations of reduced homocysteine in plasma compared wit h control subjects. No significant differences in reduced homocysteine concentrations were noted when asymptomatic and symptomatic HIV-infec ted patients were compared, and we did not find any relation between r educed homocysteine concentrations and other markers of immunodeficien cy. The HIV-infected patients had normal total homocysteine concentrat ions. The reduced cysteinylglycine concentration tended to be elevated in the patient group. No differences between HN-infected patients and control subjects were found for reduced or total cysteine. Compared w ith control subjects, the HN-infected patients had lower concentration s of methionine in plasma, and a significant correlation was found bet ween low concentrations of methionine and low CD4(+) lymphocyte counts in blood. Elevated concentrations of reduced homocysteine could possi bly contribute to formation of reactive oxygen species, leading to acc elerated immunologic deterioration and increased HIV replication.