Types of Immunoglobulins In Multiple Myeloma
The types of immunoglobulins (antibodies) produced by multiple myeloma cells often vary between myeloma patients. The myeloma proteins crowd out the normally functioning immunoglobulins, resulting in high levels of protein in blood. The proliferation of abnormal immunoglobulins offer no benefit to the body, ultimately leading to many detrimental health effects such as, kidney impairment, interference with blood cell production or an impaired immune system.
Each immunoglobulin is made up of four protein chains: two long chains (called heavy chains) and two shorter chains (called light chains). Immunoglobulins are classified into one of five classes according to its heavy chain. Each class has a unique type of heavy chain that is defined by use of a Greek letter: gamma (IgG), alpha (IgA), mu (IgM), epsilon (IgE), or delta (IgD). Normally, a plasma cell makes one of these five major classes of immunoglobulin, and each type of immunoglobulin has a slightly different function in the body. Doctors measure these monoclonal proteins with a blood test called electrophoresis. The immunoglobulin class normally present in the largest amounts in blood is IgG, followed by IgA and IgM. IgD and IgE are present in very small amounts in the blood. IgG accounts for about 60% to 70% of all multiple myeloma cases, and IgA accounts for about 20% of cases. Immunoglobulin light chains are defined by use of the Greek letters kappa or lambda.
The proteins produced by the multiple myeloma cells help determine the type of multiple myeloma. Understanding the proteins also involved also allows doctors to determine the best approach for multiple myeloma treatment. The five classes of immunoglobulins are present in most cases of symptomatic myeloma. In some cases, the plasma cells may produce incomplete immunoglobulins (light chain myeloma), or they may not secrete them at all (non-secretory myeloma).