Detection of human IgG antibodies against free N-acetyl-L-cysteine.

Human antibodies of the IgG type reacting with free N-acetyl-cysteine are detectable with an appropriate immunoconjugate. Free cysteine, homocysteine and glutathione, but not cystine, interfere with the antibodies. The interference with cysteine and homocysteine is frequently reduced after nitrosylation of these amino acids. The interference with glutathione is frequently amplified after nitrosylation of this oligopeptide. The antibodies react weakly with whole red blood cells. Autoantibodies of this type may explain the wasting observed in untreated tuberculosis patients and in AIDS patients.