Bence Jones protein

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A Bence Jones protein is a monoclonal globulin protein found in the blood or urine. Finding this protein in the context of end-organ manifestations such as malignant bone marrow cancer, renal failure, lytic bone disease, or anemia, or large numbers of plasma cells in the bone marrow of patients can be diagnostic of multiple myeloma, in which it is present in 2/3 of cases.^[1]

The proteins are antibody immunoglobulin free light chains (paraproteins) and are produced by neoplastic plasma cells. They can be kappa (most of the time) or lambda.^[1] The light chains can be immunoglobulin fragments or single homogenous immunoglobulins. They are found in urine as they are small and hence easily cleared by the kidneys. 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. These tests are essential in patients suspected of having Bence Jones proteins in their urine as these proteins don't react with the reagents normally utilized in urinalysis dipsticks. This leads to false negative results in people with Bence Jones proteins in their urine undergoing standard urinalysis. There are various rarer conditions which can produce Bence Jones proteins, such as Waldenström's macroglobulinemia and other malignanices.

The Bence Jones protein was described by the English physician Henry Bence Jones in 1847 and published in 1848.^[2] The protein was later sequenced by Frank Putnam at the laboratory of Fred Sanger in Cambridge, who was the first to report the entire sequence.

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