Bence Jones Cryoglobulinuria: Characterization of a Urinary κ Light Chain Cryoglobulin

Abstract

Bence Jones protein with cryoglobulin properties is rare. One of the earliest reports of Bence Jones cryoglobulinuria was made by Alper in 1966 (1) on a patient with multiple myeloma who had a λ Bence Jones cryoglobulin (cryo) in the urine. In this letter, we report a patient with κ Bence Jones cryoglobulinuria. We performed physicochemical analysis of the cryo protein and compared it with a noncryo monoclonal urinary κ light chain to improve our understanding of the molecular basis of urine cryoglobulin formation. The patient was a 73-year-old male who had clinical and laboratory findings consistent with multiple myeloma. Serum immunofixation revealed a monoclonal κ light chain. Urine protein electrophoresis and immunofixation of a randomly collected urine sample revealed the presence of a monoclonal κ Bence Jones protein. This urine sample formed a gel at 4 °C, which disappeared when the sample was warmed to 37 °C. As a control, we used the urine from a myeloma patient with κ Bence Jones protein without cryo formation. We performed single-dimension sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS-PAGE) on the control and cryo urine samples, which revealed a single band …