Bence Jones protein
Encyclopedia
Globulin
Globulin is one of the three types of serum proteins, the others being albumin and fibrinogen. Some globulins are produced in the liver, while others are made by the immune system. The term globulin encompasses a heterogeneous group of proteins with typical high molecular weight, and both...
protein
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...
found in the blood
Blood
Blood is a specialized bodily fluid in animals that delivers necessary substances such as nutrients and oxygen to the cells and transports metabolic waste products away from those same cells....
or urine
Urine
Urine is a typically sterile liquid by-product of the body that is secreted by the kidneys through a process called urination and excreted through the urethra. Cellular metabolism generates numerous by-products, many rich in nitrogen, that require elimination from the bloodstream...
, with a molecular weight of 22-24 kDa
Atomic mass unit
The unified atomic mass unit or dalton is a unit that is used for indicating mass on an atomic or molecular scale. It is defined as one twelfth of the rest mass of an unbound neutral atom of carbon-12 in its nuclear and electronic ground state, and has a value of...
.
Finding this protein is often suggestive of multiple myeloma
Multiple myeloma
Multiple myeloma , also known as plasma cell myeloma or Kahler's disease , is a cancer of plasma cells, a type of white blood cell normally responsible for the production of antibodies...
or Waldenstrom's macroglobulinemia.
Bence Jones proteins are particularly diagnostic of multiple myeloma in the context of end-organ manifestations such as renal failure
Renal failure
Renal failure or kidney failure describes a medical condition in which the kidneys fail to adequately filter toxins and waste products from the blood...
, lytic (or "punched out") bone lesions, anemia
Anemia
Anemia is a decrease in number of red blood cells or less than the normal quantity of hemoglobin in the blood. However, it can include decreased oxygen-binding ability of each hemoglobin molecule due to deformity or lack in numerical development as in some other types of hemoglobin...
, or large numbers of plasma cells in the bone marrow
Bone marrow
Bone marrow is the flexible tissue found in the interior of bones. In humans, bone marrow in large bones produces new blood cells. On average, bone marrow constitutes 4% of the total body mass of humans; in adults weighing 65 kg , bone marrow accounts for approximately 2.6 kg...
of patients. Bence Jones proteins are present in 2/3 of multiple myeloma cases.
The proteins are immunoglobulin light chain
Immunoglobulin light chain
]The immunoglobulin light chain is the small polypeptide subunit of an antibody .A typical antibody is composed of two immunoglobulin heavy chains and two Ig light chains.-In humans:...
s (paraprotein
Paraprotein
A paraprotein is an immunoglobulin or immunoglobulin light-chain that is produced in excess by the clonal proliferation of plasma cells. Detection of paraproteins in the urine or blood is most often associated with benign MGUS , where they remain "silent", and multiple myeloma. An excess in the...
s) 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, sometimes induced by hypercalcemia from the calcium released as the bones are destroyed or from the light chains themselves. The light chains have traditionally been detected by heating or electrophoresis
Electrophoresis
Electrophoresis, also called cataphoresis, is the motion of dispersed particles relative to a fluid under the influence of a spatially uniform electric field. This electrokinetic phenomenon was observed for the first time in 1807 by Reuss , who noticed that the application of a constant electric...
of concentrated urine
Urine
Urine is a typically sterile liquid by-product of the body that is secreted by the kidneys through a process called urination and excreted through the urethra. Cellular metabolism generates numerous by-products, many rich in nitrogen, that require elimination from the bloodstream...
. More recently serum free light chain assays
Serum Free Light Chain Measurement
Measurement of immunoglobulin free light chains in serum has recently become possible as an alternative to the analysis of Bence Jones proteins in urine. These tests are used as an aid in the diagnosis and monitoring of multiple myeloma and related disorders. There are two types of immunoglobulin...
have been utilised in a number of published studies which have indicated superiority over the urine tests, particularly for patients producing low levels of monoclonal free light chains, as seen in nonsecretory multiple myeloma and AL amyloidosis. This is primarily because of the re-absorption of free light chains in the kidneys, creating a "threshold" of light chain production which must be exceeded before measurable quantities overflow into the urine. As such, urinalysis is a fickle witness to changing free light chain production.
There are various rarer conditions that can produce Bence Jones proteins, such as Waldenström's macroglobulinemia and other malignances.
The Bence Jones protein was described by the English physician Henry Bence Jones
Henry Bence Jones
Henry Bence Jones was an English physician and chemist.- Biography :He was born at Thorington Hall, Yoxley, Suffolk, the son of Lieutenant Colonel William Jones, an officer in the 5th Dragoon Guards, and Matilda Bence...
in 1847 and published in 1848. 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.