Abnormalities of immune regulation in patients with IgA mesangial glomerulonephritis (Berger's disease).

Regulation of the immune response was studied in 22 patients with IgA nephropathy. A significant increase in the IgA production by Pokeweed-stimulated peripheral mononuclear cells maintained in culture for seven days was observed. These patients had significantly less IgA suppressor cell activity, as assessed by the Concanavalin A-generated suppressor cell assay, than the normal controls. The fact that most of the patients studied had increased activity of helper T cells on IgA synthesis, together with an augmentation in the percentage of OKT4+ cells, suggest that the abnormalities in helper T cell function might be the primary defect in this nephropathy. The existence of similar alterations in some of the healthy relatives of the patients further supports a genetic basis for susceptibility to this disease.