AA amyloidosis (reactive systemic amyloidosis) is composed of amyloid A protein derived from which serum precursor?

• A Immunoglobulin light chains — produced by plasma cell dyscrasia
• B Serum amyloid A (SAA) — an acute phase reactant synthesized by the liver ✓
• C Transthyretin — a transport protein for thyroid hormone and retinol
• D Beta-2 microglobulin — a component of MHC class I

Explanation

AA amyloidosis deposits amyloid A protein, a cleavage product of serum amyloid A (SAA), an apolipoprotein synthesized by hepatocytes as an acute phase reactant elevated chronically in inflammatory conditions like rheumatoid arthritis, tuberculosis, and bronchiectasis. AL amyloidosis is derived from immunoglobulin light chains in plasma cell dyscrasias. ATTR amyloidosis involves transthyretin (mutant in familial forms, wild-type in senile cardiac amyloidosis). Beta-2 microglobulin forms amyloid in long-term dialysis patients (Abeta2M amyloidosis).

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.