HEAT-INSOLUBLE CRYOGLOBULIN IN A PATIENT WITH ESSENTIAL TYPE-I CRYOGLOBULINEMIA AND MASSIVE CRYOGLOBULIN-OCCLUSIVE GLOMERULONEPHRITIS

We report a case of type I essential cryoglobulinemia with massive cry oglobulin-occlusive glomerulonephritis, in which the clinical course a nd the physical characteristics of the cryoglobulin were unusual. Nine years before appearance of cryoglobulin, this M-year-old man noted ed ema and purpura of the lower extremities. Renal biopsy performed 2 yea rs later showed large amounts of amorphous, weakly eosinophilic, weakl y periodic acid-Schiff (PAS)-positive materials occluding the glomerul ar capillaries. Immunostaining showed the material to be weakly immuno globulin (Ig) G positive, and electron microscopy showed homogeneous, electron-dense deposits. Nephrotic syndrome and azotemia did not respo nd to steroid treatment, and dialysis was begun 5 years after the biop sy. A small amount of cryoglobulin was first detected 2 years later, 9 years after the onset of disease. The cryoglobulin had a white gelati nous appearance, was resistant to resuspension, and did not redissolve when rewarmed to 37 degrees C. Immunoelectrophoresis of the cryoglobu lin, which partially dissolved at 54 degrees C, showed it to be compos ed of monoclonal IgG-kappa and a small amount of albumin. We consider that the unusual physical characteristics of the cryoglobulin in this case precipitated a massive cryoglobulin-occlusive glomerulonephritis, which progressed to end-stage renal failure in the absence of signifi cant cryoglobulinemia during the initial onset of disease. (C) 1995 by the National Kidney Foundation, Inc.