Morphologic alterations of the proximal tubules in light chain-related renal disease

Previous studies from our laboratory have shown that human immunoglobulin light chains (LC) can be toxic to the epithelium of the rat proximal tubule. To examine the toxicity of monoclonal LC's in man, 11 kidney specimens (EXP group) obtained from patients with monotypical LC-related renal disease (7 lambda, 4 kappa), documented by the presence of monoclonal LC's in the serum or urine and in the tissue, were examined by light, immunofluorescence, electron, and immunoelectron microscopy. This EXP group had monotypical LC deposition in the tubules and/or the glomeruli and did not have evidence of intraluminal LC precipitation and cast formation, which alters tubule morphology. A control group (CON; N = 12) of kidney specimens was obtained from patients who had proteinuria greater than 2.5 g/24 hr and mean age (49 +/- 4 vs. 59 +/- 3 years; P = NS), serum creatinine concentration (2.4 +/- 0.5 vs. 3.2 +/- 1.5 mg/dl; P = NS) and creatinine clearance (65 +/- 13 vs. 63 +/- 12 ml/min; P = NS) similar to the EXP group. All of the EXP specimens demonstrated varying degrees of proximal tubule damage, manifested by cell vacuolation, desquamation, loss of the luminal brush border, and, often, coagulation necrosis.(ABSTRACT TRUNCATED AT 250 WORDS)