Types of Myeloma

The type of myeloma corresponds to the particular type of immunoglobulin or the light chain (kappa or lambda type) that the myeloma cells produce. The most common type of myeloma is IgG, which accounts for about 60% to 70% of all cases. IgA accounts for about 20% of cases. 

Another type of myeloma is light chain myeloma, which occurs in about 15% to 20% of individuals with the disease. In this type of myeloma, the myeloma cells produce incomplete immunoglobulins—they contain only the light chain portion (and not the heavy chains). The light chain portion is also known as Bence Jones protein, after the chemist who discovered the light chains. Thus, light chain myeloma is also referred to as Bence Jones myeloma.

With light chain myeloma, M protein is found primarily in the urine rather than the blood. Bence Jones proteins may deposit in the kidney and clog the tiny tubules that make up the kidney’s filtering system, which can eventually cause kidney damage and subsequently kidney failure.

A rare form of myeloma called nonsecretory myeloma affects about 1% to 2% of individuals with myeloma. In this form of the disease, the level of M protein produced by myeloma cells is too low to be detected by standard testing.