Amyloidosis was first described in the 19th Century, but only in recent years have significant advances been made in understanding the disease. We now define amyloidosis as a group of diseases in which one or more organ systems in the body accumulates protein deposits. There are three major types of amyloidosis that are all very different from each other, and each one has a two-letter code. Each code begins with an A, for amyloid. The second letter stands for the protein which makes up the deposits that accumulate.
Primary amyloidosis is a plasma cell disorder and occasionally occurs with multiple myeloma.
The deposits in this type of the disease are made up of immunoglobulin light chain proteins, so it is coded AL for amyloid light chain. These light chain proteins are created in the bone marrow by dysfunctioning plasma cells. This is the most common type of amyloidosis in the United States and is usually treated with chemotherapy. Primary amyloid is not associated with any other diseases. Secondary amyloid is caused by a chronic infection or inflammatory disease such as rheumatoid arthritis, familial Mediterranean fever, osteomyelitis, or granulomatous ileitis.