KAPPA-LIGHT CHAIN GLOMERULOSCLEROSIS IN MULTIPLE-MYELOMA

Abstract

Kappa(K) L chains were demonstrated by immunofluorescence microscopy in the renal basement membranes of 6 of 10 patients with multiple myeloma subjected to kidney biopsy. Nodular glomerulosclerosis was present in 2 patients but the remainder showed only minor light microscopic abnormalities. Deposition of .kappa. L chains in renal basement membranes may be a frequent cause of kidney disease in multiple myeloma. This deposition may be detected with EM by the demonstration of granular dense transformation of basement membranes. Occassionally there is syntemic vascular deposition of .kappa. L chains which may be difficult to distinguish from amyloid but lacks a fibrillar character. The tissue effects of L chains in multiple myeloma seem likely to be more extensive than their deposition in renal tubules. There appears to be a greater tendency for .kappa. L chains to accumulate in renal and systemic basement membranes but the mechanisms governing this deposition are unknown.