Immunologic effects of hydralazine in hypertensive patients

Twenty-seven hypertensive patients (23 blacks, 4 whites) treated with hydralazine had frequent serologic evidence of autoimmunity. However, only 1 patient developed a lupus syndrome. Acetylator phenotype influenced the autoimmune response; slow acetylators had a higher incidence and titers of autoantibodies. The lupus patient not only had high titers of autoantibodies but they were predominantly IgG in contrast to the predominant IgM antibodies found in other slow acetylators. Hydralazine treatment did not alter cell-mediated immune responses and hydralazine antibodies were not detected. However, half the patients tested who received hydralazine had positive lymphoproliferative responses to the drug.