What are Plasma Cell Neoplasms?

A plasma cell neoplasm is a disease which causes abnormal growth of plasma cells in bone marrow. Multiple myeloma is a type of plasma cell neoplasm in which abnormal plasma cells grow in the bone marrow and form tumors. Normally, plasma cells make antibodies that fight infections. However, plasma cell neoplasms are seen when plasma cells make an antibody protein called an M protein that does not help fight infection. The M proteins build up in bone marrow leading to thicken blood or damaged kidneys.

Myeloma cells produce the same immunoglobulin protein, called monoclonal (M) protein or paraprotein, in large quantities. Although the specific M protein varies vary from patient to patient, it is always exactly the same in any one patient. When blood or urine is processed in a laboratory test called electrophoresis, these M proteins show up as a “spike” in the results.

M protein offers no benefit to the body, and it crowds out the functional immunoglobulins. In addition, levels of functional immunoglobulin are depressed in individuals with multiple myeloma. Although the process is not completely understood, it appears that the functional immunoglobulin made by existing normal plasma cells breaks down more quickly in patients with multiple myeloma than in healthy individuals.