Localization of Bence Jones proteins in the kidney of myeloma patients.

Six cases of multiple myeloma were studied regarding functions and pathology of the kidney. Glomerular changes were minimal, whereas tubular and interstitial changes were noted in all cases. Tubular cells were degenerative and atrophic in cases excreting more than 3 g BJP daily in the urine. Cases without BJP had only minor changes. The most severe impairment of renal function was found in a patient with Fanconi's syndrome, with hypercalcemia, calcium in the tubules, tubular atrophy and interstitial fibrosis. In attempting to correlate immunoglobulin abnormalities with renal histology, immunoperoxidase staining of immunoglobulin heavy and light chains were done on kidney sections. Glomerular and interstitial tissues gave a definitely negative reaction. In contrast, positive staining of light chain of corresponding type wrs found in the cytoplasma of the tubules and most tubular casts, with different degrees possibly in accord with the amounts of BJP.