Myeloma protein

The concept and the term paraprotein were introduced by the Berlin pathologist Dr Kurt Apitz in 1940,^[1] then the senior physician of the pathological institute at the Charité hospital.^[2]

Paraproteins allowed the detailed study of immunoglobulins, which eventually led to the production of

Myeloma is a malignancy of plasma cells. Plasma cells produce immunoglobulins, which are commonly called antibodies. There are thousands of different antibodies, each consisting of pairs of heavy and light chains. Antibodies are typically grouped into five classes: IgA, IgD, IgE, IgG, and IgM. When someone has myeloma, a malignant clone, a rogue plasma cell, reproduces in an uncontrolled fashion, resulting in overproduction of the specific antibody the original cell was generated to produce. Each type of antibody has a different number of light chain and heavy chain pairs. As a result, there is a characteristic normal distribution of these antibodies in the blood by molecular weight.

When there is a malignant clone, there is usually overproduction of a single antibody, resulting in a "spike" on the normal distribution (sharp peak on the graph), which is called an M spike (or monoclonal spike). People will sometimes develop a condition called MGUS (Monoclonal gammopathy of undetermined significance), where there is overproduction of one antibody but the condition is benign (non-cancerous). An explanation of the difference between multiple myeloma and MGUS can be found in the International Myeloma Foundation's Patient Handbook.^[3] and Concise Review^[4]

Detection of paraproteins in the

Serum free light-chain measurement can detect free light chains in the blood. Monoclonal free light chains in the serum or urine are called Bence Jones proteins.

Interpretation upon detection

• Tuftsin
• Monoclonal gammopathy of undetermined significance
• Smouldering myeloma
• Multiple myeloma
• Plasma cell dyscrasia

References