Immunofluorescent studies of the myeloma kidney with special reference to light chain disease

Multiple Myeloma

“…The diagnosis of cast nephropathy is based on the demonstration of tubular casts in the distal nephron that are composed of Ig light chains, and the light chain in the cast is the same as that in the serum and urine (31); immunofluorescence microscopy demonstrates staining restricted to one or the other light chain (Figure 1). The casts contain either Ig light chain, Ig, and other serum proteins (31)(32)(33)(34)(35)(36), including Tamm-Horsfall glycoprotein. In hematoxylin-and eosin-stained sections, the casts are intensely eosinophilic, and they seem "brittle" because they are lamellated and fractured frequently (Figure 2).…”

Proximal Tubular Cell, Proteinuria and Tubulo-lnterstitial Scarring

“…It has been suggested that renal failure may be the result of tubular obstruction from cast formation. However, as long ago as 1968 Levi et al [65] noted that renal failure correlates more closely with tubular atrophy than with casts. A number of changes in tubular function on exposure to light chains have been found.…”

Pathogenesis of Renal Disease in Monoclonal Gammopathies: Current Concepts

“…Two phenomena may then occur: direct cel lular toxicity by the reabsorbed light chains, and precipitation of non-reabsorbed material in the distal and collecting tubes. In fact, light chains also induce precipitation of TammHorsfall mucoprotein, this explaining that casts are never purely constituted of light chains, but have a very variable composition [5,11]. It is not well established whether tubular obstruction by the casts or associated tubular lesions play a prominent role in the genesis of renal failure.…”