Multiple myeloma manifests as different types and subtypes. These types are based on the immunoglobulin (protein) produced by the myeloma cell. Normally, the various immunoglobulins have different functions in the body. Each immunoglobulin is made up of two heavy chains and two light chains.
There are five types of heavy protein chains: G, A, D, E, and M. There are two types of light protein chains: kappa (κ) and lambda (λ). Furthermore, there are different subtypes of myeloma.
- Normal plasma cells secrete immunoglobulins (antibodies) to fight infections. Immunoglobulins are proteins that attach to substances entering the body that the body recognizes as foreign. Normal immunoglobulins are called "polyclonal protein." Myeloma cells, which are cancerous plasma cells, secrete monoclonal protein, an abnormal immunoglobulin (antibody) that is ineffective at fighting infection.
- Intact immunoglobulins — those made by healthy plasma cells and those made by myeloma cells — are constructed of two heavy chains and two light chains that are bound together.
- There are five possible types of immunoglobulin (abbreviated "Ig") heavy chains: IgG, IgA, IgD, IgE, and IgM.
- There are two possible types of light chains, either kappa (κ) or lambda (λ).
- Myeloma cells produce immunoglobulins made up of only one type of heavy chain (G, A, D, E, or M) and one type of light chain (kappa or lambda). The most common type of myeloma is IgG kappa, in which the myeloma cells secrete an immunoglobulin made from two IgG heavy chains bound to two kappa light chains.
- About 15% of patients have a type of myeloma in which the myeloma cells secrete only light chain protein and no heavy chains. This is called "light chain myeloma" or "Bence-Jones myeloma" (after the doctor who discovered it).
- In 1%-2% of patients, the myeloma cells produce very little or no monoclonal protein of any type. This is called "non-secretory myeloma."
- Your doctor will order tests to identify your type of myeloma. It's important to know which type you have so you can follow your test results and know if your level of monoclonal protein is stable, increasing, or decreasing.
If you have been diagnosed with AL amyloidosis, light chain deposition disease, Waldenström's macroglobulinemia, or POEMS syndrome, please see the IMF's Patient Handbook for more information.
Subtypes of immunoglobulins
Types of Myeloma
IgG k or λ
IgA or λ
IgD, E, or M
|Light Chain only or
Bence Jones (BJ) myeloma:
k or λ types
k or λ subtypes