IDENTIFICATION OF SELECTIVE IMMUNOGLOBULIN-A DEFICIENCY BY RENAL BIOPSY

We report three cases of selective immunoglobulin A (IgA) deficiency i n which lack of direct immunofluorescent staining for IgA on renal bio psy specimens contributed to the diagnosis. In two patients, one with systemic lupus erythematosus and the other having asthma with nephroti c syndrome, the diagnosis of IgA deficiency was suggested by the compl ete absence of IgA on the renal biopsy. In the third patient, a renal transplant recipient, initial biopsies demonstrated donor-derived IgA, which disappeared on subsequent biopsies. The diagnosis of IgA defici ency was confirmed in all three patients by serologic quantification o f IgA. (C) 1995 by the National Kidney Foundation, Inc.