In secondary (AA) amyloidosis, the amyloid fibrils are derived from SAA (serum amyloid A), an acute phase reactant. SAA is primarily synthesized by:

• A B lymphocytes in germinal centers
• B Plasma cells secreting monoclonal light chains
• C Beta cells of pancreatic islets
• D Hepatocytes, as an acute phase protein upregulated by IL-6 and IL-1 ✓

Explanation

SAA (serum amyloid A) is an apolipoprotein synthesized primarily by hepatocytes as a major acute phase reactant, with production dramatically upregulated in response to IL-6, IL-1, and TNF during inflammation. In chronic inflammatory states (rheumatoid arthritis, TB, osteomyelitis, Crohn disease, periodic fever syndromes), persistently elevated SAA is proteolytically cleaved to the AA fragment, which misfolds and deposits in tissues. The kidney (medulla and cortex) is the most commonly affected organ. In contrast, AL amyloid (primary amyloidosis/myeloma-related) is derived from immunoglobulin light chains.

Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.