Finger print deposits of the kidney in pure monoclonal IgG kappa cryoglobulinemia.

In a male patient with pure monoclonal IgG kappa cryoglobulin associated with the nephrotic syndrome, finger print deposits were observed in the subendothelial space and mesangial matrix of the kidney by electron microscopy. The structure was similar to a unique tubular crystal structure of IgGl kappa cryoglobulin which was reported by Bogaars et al. [1973] in the serum of a patient with multiple myeloma. It was therefore supposed that the finger print deposits in the kidney of this patient were the precipitation of the monoclonal IgG kappa cryoglobulin in serum.