Hydralazine causes nonspecific binding of antibodies to human lymphocytes in vitro

Abstract

In vitro incubation of human lymphocytes or a continuous human Jurkat T cell line with hydralazine (1-hydrazinophthalazine), a widely used antihypertensive agent, produced a nonspecific binding of various antibodies to the cells. This phenomenon was found to produce increases in staining of mitogen-stimulated and mitogen-unstimulated human lymphocytes and Jurkat cells with a variety of antibodies recognizing T and B cell antigens. The increase in nonspecific binding was greatest at 10(-2) M hydralazine, but was seen with concentrations as low 10(-7) M, which is comparable to the serum concentrations of patients prescribed hydralazine. The binding of antibodies is not connected with significant decreases in the cell viability. This property of hydralazine may cause misinterpretation of certain immunological tests employing the antibodies.