Bence Jones Protein and Paraproteins

Key points

• • A paraprotein (M-band) is a single type of immunoglobulin produced in excess by one clone of plasma cells, seen as a sharp band on protein electrophoresis.
• • Bence Jones protein is free immunoglobulin light chains that pass into the urine because they are small enough to be filtered by the kidney.
• • Bence Jones protein has an unusual property: it precipitates when the urine is warmed to about 50 to 60 degrees Celsius and redissolves on further heating.
• • These proteins are typical of multiple myeloma and related plasma-cell disorders, and the light chains can damage the kidney.
• • Serum and urine protein electrophoresis, with immunofixation, are used to find and identify the abnormal protein.