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The aim of this study was to determine the prevalence of systemic AA amyloidosis (AAa), islet amyloidosis (IA) and liponecrotic pancreatitis (LnP) including acute liponecrotic (aLnP), acute relapsing liponecrotic (aRelLnP), and chronic liponecrotic pancreatitis (chrLnP) in rheumatoid arthritis (RA), and to analyse the possible relationship between them.Patients and methods: At the National Institute of Rheumatology 11558 patients died between 1969 and 1998; among them 234 with RA, and all of them were autopsied. RA was confirmed clinically according to the criteria of the American College of Rheumatology (ACR). The diagnosis of DM was based on clinical data. Tissue samples of pancreas were available for histologic evaluation in 164 of 234 patients. AAa, IA and LnP were diagnosed histologically. Demographics of different patient cohorts were compared with the Student (Welch) t probe. The relationships between AAa and IA, furthermore between IA and DM or LnP (including aLnP, aRelLnP, chrLnP) were analyzed by Pearson’s chi-squared (c2) test.Results: AAa complicated RA in 42 (25.61%) of 164 patients. IA localized to the islets of Langerhans was observed in 16 (9.76%) of 164 pancreases. Clinically diagnosed DM was associated with RA in 31 (18.90%) of 164 patients. Pancreatitis with multiple liponecrotic foci (LnP) was found in 19 (11.58%) of 164 patients; aLnP existed in 9 (47.37%), aRelLnP in 4 (21.05%), and liponecrotic foci in combination with chronic fibrotic pancreatitis (chrLnP) in 6 (31.58%) of these 19 patients.Discussion and conclusions: There was no significant difference between female and male RA patients associated with AAa, IA, DM and LnP. The age, sex and onset of disease did not influence basically the prevalence of AAa, IA, DM and LnP except male patients with IA, whose mean age at death was significantly higher than the general RA population. IA (fibrillar amyloid IAPP deposits -AIAPP) is related to the activity of b cells and may presumably be a faulty product of b-cells (normal islets of Langerhans do not contain IA deposits). The progressive deposition of IAPP prohormon fragments inhibits the function of b-cells because of their toxic effect and/or blocking mechanically the blood supply of b-cells and they “die in their own product”. The significant correlation between IA and DM refers to a close connection between them, but not necessarily a direct cause and effect relationship; it may be an indirect result of damaged (apoptotic) b-cells. The early stage of IA is characterized by minimal IAPP deposits involving only a few islets, which represents a clinically latent DM, and the advanced stage of IA is characterized by massive IAPP deposits involving most of the islets, which correspond to clinically manifest DM. Based on the positive and significant correlation between IA and clinically not diagnosed DM, IA may be a good indicator of potential DM in the latent stage of disease. Therefore we recommend that all biopsy material and surgical specimens of pancreas to be tested for IA or IAPP deposition. |
