Screening for amyloid deposition by subcutaneous fat tissue aspiration technique in rheumatoid arthritic patients and investigating its clinical significance in Iran

Aim: This study examined the frequency of secondary amyloidosis in Iranian patients with rheumatoid arthritis (RA) in order to determine its clinical significance. Methods: A total of 220 RA patients (167 female, 53 male), with minimum disease duration of 5 years, were included in this prospective study over a period of about 2 years. Abdominal subcutaneous fat-pad aspiration (ASFA) method was used in obtaining specimens from all subjects. All of the specimens were examined for apple-green birefringence under polarized light microscope. Amyloid deposits were graded from 1+ to 3+. Clinical, radiological, and laboratory characteristics of the patients were assessed and recorded. Results: Amyloid deposition was detected in 11 (5) of the fat smears stained with Congo red stain. All of the samples had minimal (1+) amyloid deposits. In this study, amyloid-positive cases showed clinically significant symptoms; six of the patients (55) presented with proteinuria, and seven other cases (64) presented with severe constipation. Conclusion: Abdominal fat amyloid deposition was found to be uncommon in adult Iranian RA patients. In up to half of the patients the deposits were subclinical. A longer follow-up and larger multicentric collaborative study is needed to determine the significance of subclinical amyloid deposits. © 2007 Asia Pacific League of Associations for Rheumatology and Blackwell Publishing Asia Pty Ltd