IgA synthesis by peripheral blood mononuclear cells from normal and selectively IgA deficient subjects.

IgA secretion and intracellular IgA synthesis by PWM-stimulated peripheral blood lymphocytes from normal and IgA deficient subjects were measured by radioimmunoassay. Cultured lymphocytes from eleven out of twelve IgA deficient subjects had impaired or undetectable IgA production. Measurement of intracellular IgA showed that the defect was more basic than simply defective secretion by IgA plasma cells. Co-culture of lymphocytes from IgA deficient and normal subjects revealed defects in both the B and T cell populations of IgA deficient subjects. In one subject the defect was in the T cells, in another the B cells, and in two others both T and B cells were defective.