ABSTRACT
BACKGROUND: We experienced a patient with multiple myeloma whose urine contained a considerable amount of Bence Jones protein (BJP), which demonstrated poor thermal reactivity in heat coagulation test. The mechanism for this phenomenon was assessed. METHODS: Immunoelectrophoretic analyses reveal that a band corresponding to BJP in the urine had 2,600 Dalton by reduction after glycosidase treatment, but not after sialidase treatment. In addition, the glycosidase-treated urine tested positive in heat coagulation test. CONCLUSIONS: Glycosylation of the immunoglobulin light chain, which has rarely been seen, is the cause of the unexpected behavior of this patent's BJP in heat coagulation tests.
Subject(s)
Bence Jones Protein , Multiple Myeloma , Bence Jones Protein/metabolism , Blood Coagulation Tests , Glycosylation , Hot Temperature , Humans , Immunoglobulin Light ChainsABSTRACT
BACKGROUND: We encountered a rare case of Waldenstrom macroglobulinemia with temporary appearance of 7S IgM half molecule and with monoclonal proteins binding to agarose gel. METHODS: The patient's serum and urine were analyzed using sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting. The N-terminal amino acid sequences of the IgM with abnormal mass (68 kDa) were determined and compared with those of known immunoglobulin. RESULTS: The 68 kDa IgM consisted of a defective µ chain (36 kDa) and an intact κ chain. N-terminal amino acid sequence analysis demonstrated that the defective µ chain had the variable region of IgM. The agarose gel-binding ability of the IgM-κ M-protein was lost after reduction or alkaline treatment of serum. CONCLUSIONS: The 7S half molecule IgM in the present case may miss a large part of the constant region of the µ chain.