Page 112 - GTM-4-1

Global Translational Medicine

ORIGINAL RESEARCH ARTICLE
Systemic and gastrointestinal amyloid A

amyloidosis in rheumatoid arthritis: A post-
mortem clinicopathologic study of 161 cases

Miklós Bély * and Ágnes Apáthy 2
1
1 Department of Pathology, Hospital of the Order of the Brothers of Saint John of God, Budapest,
Hungary
2 Department of Rheumatology, St. Margaret Clinic, Budapest, Hungary

Abstract

Amyloidosis syndromes are characterized by the extracellular deposition of
fibrillar proteins, with 22 systemic and 27 localized forms identified. Among these,
amyloid A (AA) amyloidosis is a complication of chronic inflammatory diseases,
particularly rheumatoid arthritis (RA), and can affect multiple organs, including the
gastrointestinal (GI) tract. The study aimed to determine the prevalence and severity
of systemic AA amyloidosis (sAAa) and GI AA amyloidosis (giAAa) in RA, evaluate their
role in mortality, and clarify the diagnostic value of GI biopsy. A total of 161 randomly
selected autopsy patients with RA were studied. In this study, the GI tract refers
specifically to the stomach, small intestine, and large intestine. The presence and
*Corresponding author:
Miklós Bély extent of sAAa and giAAa were assessed histologically; with AA deposition quantified
(dr.bely.miklos@gmail.hu) using a semi-quantitative visual estimation scale ranging from 0 to 3. Demographic
Citation: Bély M, Apáthy Á. differences between patient cohorts were analyzed using the Student’s (Welch) t-test.
Systemic and gastrointestinal sAAa was identified in 34 (23.13%) of the 161 patients. Among these cases, tissue
amyloid A amyloidosis in blocks containing one or more sections of the GI tract were available in 31 patients. In
rheumatoid arthritis: A post-
mortem clinicopathologic study 29 of these cases, AA deposits were detected in branches of blood vessels and various
of 161 cases. Global Transl Med. tissue structures of the GI tract, while giAAa was histologically excluded in two patients
2025:4(1):104-125. with sAAa. sAAa and giAAa may develop in both sexes and can occur at any stage in
doi: 10.36922/gtm.5325
the course of RA. These conditions represent progressive and cumulative processes,
Received: October 21, 2024 initially affecting only a few structures within various organs and expanding in the
Revised: January 12, 2025 later stages of the disease. Although giAAa does not appear to be a life-threatening
complication of RA, it emerges as an early pathological feature of significant clinical
Accepted: January 20, 2025
and diagnostic importance, particularly as an optimal biopsy site.
Published online: March 7, 2025
Copyright: © 2025 Author(s). Keywords: Rheumatoid arthritis; Systemic amyloid A amyloidosis; Amyloid A amyloidosis
This is an Open-Access article
distributed under the terms of the of the gastrointestinal tract
Creative Commons Attribution
License, permitting distribution,
and reproduction in any medium,
provided the original work is
properly cited. 1. Introduction
Publisher’s Note: AccScience Amyloidosis syndromes are systemic or localized disorders characterized by the
Publishing remains neutral with extracellular deposition of chemically heterogeneous fibrillar proteins. To date, 49
regard to jurisdictional claims in
published maps and institutional distinct pre-cursor proteins have been identified in humans, with 22 proteins associated
affiliations. with systemic amyloidosis and 27 with localized forms. 1

Volume 4 Issue 1 (2025) 104 doi: 10.36922/gtm.5325