**3.1 Amyloid light chain (AL) protein**

*Amyloid Diseases*

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**Table 1.**

*Amyloid fibril protein classification and associated disease.*

AL type amyloid is the most common amyloid in the United States. The AL chain is a clonal immunoglobulin light chain or light chain fragment, which is produced by the uncontrolled productions of antibodies by plasma cells. Lambda (λ) type (ALλ) is more common than kappa (κ) type (ALκ) light chain. This type of amyloidosis is related to monoclonal plasma cell disorders, especially multiple myeloma or other B-lymphocyte-related disorders. If we cannot determine AL type amyloidosis to a certain disease, it is categorized as primary amyloidosis. Even if we cannot demonstrate a specific disease to AL type amyloidosis, we still see monoclonal plasma cell proliferation in these patients. In either case, we can find immunoglobulin or light chain within the serum or urine. The most commonly affected organ is the kidney. The heart, peripheral nervous system, gastrointestinal tract, and respiratory tract can also be affected. A localized form of AL type amyloid can be seen in the gastrointestinal tract [2]. Amyloid heavy chain (AH) is rarely reported but also associated with monoclonal plasma cell disorder [3].
