Bence Jone's Protein is: March 2005

Ans. B: Monoclonal light chains A Bence Jones protein is a monoclonal globulin protein found in the blood or urine, with a molecular weight of 22-24 kDa. The proteins are immunoglobulin light chains (paraproteins) and are produced by neoplastic plasma cells. They can be kappa (most of the time) or lambda. The light chains can be immunoglobulin fragments or single homogeneous immunoglobulins. They are found in urine due to the kidneys' decreased filtration capabilities due to renal failure, often induced by hypercalcemia from the calcium released as the bones are destroyed. The light chains can be detected by heating or electrophoresis of concentrated urine. Light chains precipitate when heated to 50 - 60 degrees C and redisolve at 90 -100 degrees C. There are various rarer conditions that can produce Bence Jones proteins, such as Waldenstrom's macroglobulinemia.