Immunoglobulins and laboratory recognition of monoclonal proteins

Plasma cell proliferative disorders such as multiple myeloma, macroglobulinemia, and primary amyloidosis are characterized by the clonal expansion of plasma cells and their secreted monoclonal immunoglobulin. The monoclonal immunoglobulin serves as a tumor marker for the recognition of the clinical disorder as well as for monitoring disease progression, response, or relapse. Because of the wide range of biology amongst the plasma cell proliferative diseases, the recognition of a monoclonal protein may require a simple laboratory test or may require multiple approaches. Knowledge of immunoglobulin structure and genetics as well as the technologies of protein electrophoresis, immunoelectrophoresis, and quantitative free light chain (FLC) assessment is needed to fully understand the use of these markers of plasma cell proliferative disease.