Serum protein electrophoresis showing a paraprotein (peak in the gamma zone) in a patient with multiple myeloma.

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 (monoclonal gammopathy of undetermined significance), where they remain "silent",[1] and multiple myeloma. An excess in the blood is known as paraproteinemia. Paraproteins form a narrow band, or 'spike' in protein electrophoresis as they are all exactly the same protein.

Monoclonal free light chains in the serum or urine are called Bence Jones proteins.



The concept and term were introduced by the Berlin pathologist Dr Kurt Apitz in 1940,[2] at that time the Oberarzt of the pathological institute at the Charité hospital.[3]

Paraproteins allowed the detailed study of immunoglobulins, which eventually led to the production of monoclonal antibodies in 1975.

Interpretation upon detection

Blood serum paraprotein levels of more than 30 g/L is diagnostic of multiple myeloma, according to the diagnostic criteria of the International Myeloma Working Group[4], which were updated in 2009.[5] Detection of paraprotein in serum of less than 30 g/L is classified as monoclonal gammopathy of undetermined significance in cases where clonal plasma cells constitute less than 10% on bone marrow biopsy and there are no myeloma-related organ or tissue impairment.[4][5]

See also


  1. ^ Maniatis A (1998). "Pathophysiology of paraprotein production.". Ren Fail 20 (6): 821–8. doi:10.3109/08860229809045179. PMID 9834980. 
  2. ^ Apitz K. Die Paraproteinosen. Über die Störungen des Eiweißstoffwechsels bei Plasmozytomen. Virchows Arch Pathol Anat 1940;306:630-699.
  3. ^ McDevitt HO. Albert Hewett Coons. In: "Biographical Memoirs", National Academy of Sciences 1996;69:26-37. ISBN 0-309-05346-3. Fulltext.
  4. ^ a b International Myeloma Working Group (2003). "Criteria for the classification of monoclonal gammopathies, multiple myeloma and related disorders: a report of the International Myeloma Working Group". Br. J. Haematol. 121 (5): 749–57. doi:10.1046/j.1365-2141.2003.04355.x. PMID 12780789. 
  5. ^ a b Kyle RA, Rajkumar SV (January 2009). "Criteria for diagnosis, staging, risk stratification and response assessment of multiple myeloma". Leukemia 23 (1): 3–9. doi:10.1038/leu.2008.291. PMC 2627786. PMID 18971951. 

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