IgA and glomerular disease.

Serum IgA levels are raised in a proportion of children with Henoch-Schönlein disease (H. S. P.), patients with Berger's mesangial IgA disease, and in patients with glomerular lesions in association with hepatic cirrhosis. These conditions are all characterized by mesangial staining with anti-IgA antisera on immunofluorescence. It has been suggested that elevated serum IgA levels are of value in the diagnosis of these diseases. We have measured serum IgA levels by radial immunodiffusion in a variety of primary and secondary glomerular diseases. High serum IgA levels were confined to patients with glomerular IgA deposition, but were not restricted to H. S. P. and Berger's disease, nor to patients with deposition of IgA only in a mesangial pattern. Elevated salivary IgA levels were found in 3/4 patients with high serum IgA levels but we found no evidence for involvement of the secretory system in glomerular mesangial IgA deposition.