In vitro TNP-specific antibody formation by peripheral lymphocytes from patients with systemic lupus erythematosus.

Immunological reactivity in patients with systemic lupus erythermatosus (SLE) was assessed by investigating in vitro trinitrophenyl (TNP)-specific antibody formation by peripheral lymphocytes. Peripheral lymphocytes from 16 patients with SLE were cultured with TNP conjugated with horse erythrocytes (TNP-HRBC) in the presence of 2-mercaptoethanol. The hemolytic plaque assay was used to detect hapten (TNP)-specific antibody-forming cells. Peripheral lymphocytes from normal individuals failed to produce antibody to TNP, whereas SLE lymphocytes produced a significant number of plaque-forming cells. Co-culture experiments with SLE and normal lymphocytes suggested that patients with SLE have a defect in T lymphocytes, leading to abnormal antibody production.