Phenol Congo red staining enhances the diagnostic value of abdominal fat aspiration biopsy in reactive AA amyloidosis secondary to rheumatoid arthritis

OBJECTIVE: Systemic reactive AA amyloidosis is an intractable complication in patients with a long history of rheumatoid arthritis (RA). To help to more easily and reliably detect the presence of this form of amyloidosis in patients with RA and start intensive treatment as early as possible, we examined the sensitivity and usefulness of abdominal fat aspiration biopsy with phenol Congo red staining in the diagnosis of AA amyloidosis. PATIENTS AND METHODS: Ten patients were diagnosed with systemic reactive AA amyloidosis secondary to RA (all women; mean age, 70.2 +/- 6.4 years; mean disease duration of RA, 20.3 +/- 11.2 years) based on histopathological examinations of biopsied specimens mainly from the gastroduodenal mucosa. Abdominal fat aspiration biopsy was performed in these patients, and the specimens were treated with both classical alkaline and phenol Congo red staining. RESULTS: Phenol Congo red staining revealed amyloid deposits in all 10 patients, while conventional alkaline Congo red staining showed a positive result in 7 patients. In the patients with a positive result with alkaline Congo red staining, reactivity of one grade or two higher was demonstrated by the phenol Congo red method. CONCLUSION: Phenol Congo red staining is superior to the classical alkaline Congo red staining with respect to the detection of AA-amyloid deposits in biopsied abdominal fat tissue specimens. In addition to easy access and procedural safety, abdominal fat aspiration biopsy might contribute reliably to the diagnosis of systemic reactive AA amyloidosis secondary to RA when phenol Congo red staining is employed.     

Current clinical aspects of dialysis-related amyloidosis in chronic dialysis patients

The current understanding of dialysis-related amyloidosis has evolved over the past two decades. In the early 1980s, several researchers found amyloid deposits in the synovia of carpal tunnel syndrome (CTS), which have been recognized as a complication of chronic hemodialysis. The enigma was resolved in 1985, when beta2-microglobulin (beta2-m) with a molecular weight of 12,000 Da was identified as the major constitutional protein of this amyloid. Amyloid fibrils of this type that contain the sub-unit protein of human leukocyte antigens (HLA), beta2-m, deposit predominantly in osteoarticular tissues, inducing musculoskeletal symptoms such as CTS, polyarthralgia, bone cyst showing radiolucency at X-ray examination and destructive spondyloarthropathy. In addition, extra articular symptoms such as ischemic colitis, megaloglossia, and heart failure, that is, systemic involvement occasionally occur. We confirmed that the prevalence of CTS increases with duration of dialysis. Most patients with CTS associated with beta2-m amyloid deposits have undergone hemodialysis for 10 years or more. Up to 50% of patients had developed this complication after 20 years and the percentage was even higher after 25 years. General categories of therapeutic approaches for amyloidosis include prevention of onset or progression, symptomatic therapy (conservative treatment, orthopedic procedures, and physiotherapy), and renal transplantation. It is critical to elucidate the detail mechanisms of the amyloid fibril formation, and establish its radical treatment. It is also important to develop novel therapies such as cell implantation to compensate for normal kidney functions of uremic toxin protein metabolism.     

Diagnosis of amyloidosis by abdominal fat aspiration. Analysis of four years' experience

Abdominal fat aspiration samples from 443 consecutive patients were examined for amyloid after Congo red and hematoxylin staining. Of the aspirates from 83 patients known to have systemic amyloid disease prior to the biopsy, 70 (84 percent) were found to yield positive results. The results for four aspirates from patients with localized amyloid disease were negative. Of the aspirates from 356 patients of unknown clinical status referred for analysis by outside physicians, 26 (7 percent) yielded positive results for amyloid. On review of the clinical records of these 26 patients, 11 had proved systemic amyloidosis demonstrated on biopsy of another site; all had a clinical course consistent with amyloid disease. In no case was amyloid found in a fat aspiration sample from a patient without clinical evidence suggestive of systemic amyloid disease. This study supports the proposal that abdominal fat aspiration is the diagnostic procedure of choice in the evaluation of amyloidosis since it requires no specialty consultation or technical expertise, causes minimal patient discomfort, and is accompanied by virtually no risk of morbid complication. A positive result has a high predictive value of amyloid disease in patients of unknown clinical status.     

Abdominal fat aspiration biopsy and genotyping of serum amyloid A contribute to early diagnosis of reactive AA amyloidosis secondary to rheumatoid arthritis

OBJECTIVE: To detect amyloid deposits in the early phase of illness, we investigated the usefulness of abdominal fat aspiration biopsy along with genotyping of serum amyloid A (SAA) in patients with rheumatoid arthritis (RA). PATIENTS AND METHODS: We performed abdominal fat aspiration biopsy with phenol Congo red staining and determined inflammatory markers, including CRP and SAA, in 217 patients with an RA history longer than 5 years (mean age, 64.1 +/- 10.6 years). Genotypes of SAA1 and 2 were investigated in 127 patients with RA by a polymerase chain reaction-restriction fragment length polymorphism analysis. RESULTS: In the abdominal fat aspiration biopsy 17 patients (7.8%) demonstrated amyloid deposits, which were confirmed as AA type by immunostaining on biopsied tissues from other organs, and nine of them showed no clinical symptoms ascribable to amyloidosis. RA patients with amyloidosis showed significantly higher serum levels of CRP (p < 0.05) and SAA (p < 0.0001) than those without amyloidosis. In the genotyping, amyloid deposition was significantly correlated with the frequency of SAA1.3 (p < 0.005 vs. 1.1, p < 0.05 vs. 1.5). Comparison of inflammatory markers between the number of SAA1.3 alleles showed that the SAA/CRP ratio and SAA concentration were higher in the 1.3 homozygote than in the others (p < 0.05). Two patients demonstrated amyloid deposits at the second abdominal fat biopsy one year after the first, and their SAA1 genotypes were 1.3/1.5 and 1.3/1.3. CONCLUSION: In RA patients confirmed as having SAA1.3, serial examinations with abdominal fat aspiration biopsy might contribute greatly to the early detection of amyloidosis during the long-term follow-up.     

The clinical significance of amyloid fat deposits in rheumatoid arthritis: a systematic long-term followup study using abdominal fat aspiration

OBJECTIVE: To analyze the prevalence of subclinical amyloid fat deposits in patients with rheumatoid arthritis (RA) and to evaluate its clinical significance. METHODS: A cohort of 313 adult RA patients were included in this prospective observational study. Systematic abdominal subcutaneous fat aspiration (ASFA) was performed on all patients at study entry. The prevalence of visceral amyloidosis at study entry and at the end of followup was analyzed for patients with a positive ASFA test result. Followup ranged from 1 to 14 years (mean +/- SD 6.7 +/- 4.1 years). Patients with clinical and subclinical amyloidosis were compared with regard to clinical characteristics and the degree of amyloid deposits in abdominal fat. RESULTS: The first ASFA test found amyloid in the abdominal fat of 51 patients (16.3%), and subsequent ASFA tests found amyloid in the abdominal fat of 10 additional patients. At the time of the ASFA test, amyloidosis was subclinical in 45 of these 61 patients, 41 of whom were followed up. During followup, 11 of these 41 patients developed renal involvement, 5 due to amyloid nephropathy. Thus, amyloidosis remained subclinical in at least 30 of 41 patients (73%) throughout followup. Marked amyloid fat deposits were found more frequently in patients with clinical amyloidosis than in those whose amyloidosis remained subclinical at the end of followup (57% versus 22%; P = 0.04). CONCLUSION: Amyloid fat deposits are not uncommon in adult RA. In the majority of patients, the deposits do not indicate clinically evident organic dysfunction, even after several years of followup. Patients with more extensive fat deposits may have a higher risk of developing clinical amyloidosis.     

The prevalence of subclinical amyloidosis in Polish patients with rheumatoid arthritis

The aims of this study were to determine the proportion of rheumatoid arthritis (RA) patients attending hospital in whom amyloid deposits were present in abdominal fat aspiration (AFA) samples, and to assess possible risk factors for amyloid development in RA. One -hundred and twenty-one patients (16 males, 105 females) with RA referred to the Department of Rheumatology in Wroclaw between 1996 and 2001 were studied regardless of RA duration or laboratory findings. Abdominal subcutaneous fine-needle aspiration was performed, and samples of adipose tissue stained with alkaline Congo red then examined by polarized light microscopy. The presence or absence of amyloid fat deposits (AFD) was determined according to whether typical apple-green birefringence was observed. Amyloid deposits were found in 35 (29%) patients. Amyloidosis was significantly more common in males and in patients with longer disease duration. Patients with AFD had previously undergone less treatment with disease-modifying antirheumatic drugs (DMARDs) than those without AFD, and significantly fewer patients with AFD had previously taken methotrexate than those without AFD (25% vs 45%; p<0.01). Renal involvement was found in 12 of 35 patients with AFD (34%). Using the AFA technique, amyloid deposits were found commonly in RA patients, particularly in males with longer disease duration and in patients not treated intensively with DMARDs, especially methotrexate. AFA has potential useful application as a method for detecting amyloidosis before the overt occurrence of renal or other pathology related to amyloid deposits.Abbreviations AFA Abdominal fat aspiration - AFD Amyloid fat deposits - DMARDs Disease-modifying antirheumatic drugs - RA Rheumatoid arthritis     

Diagnostic approaches to AB-amyloidosis.

AB-amyloidosis, characterized by the presence of beta 2-microglobulin in the amyloid fibrils, has become an important complication of long-term renal replacement therapy. Due to the mainly musculoskeletal manifestation of the disease, standard approaches to obtain the diagnosis of amyloidosis, such as rectal biopsy or fat aspiration, often yield negative results. Currently, definitive diagnosis relies on biopsies, usually of synovial membranes or bone cystic radiolucencies. The serum level of beta 2-microglobulin, though markedly elevated, does not distinguish between patients with and without amyloid deposition. Measurements of altered, circulating beta 2-microglobulin species have not yet been evaluated in this regard. Recently, two radiopharmaceuticals, namely radiolabelled serum amyloid P component and radiolabelled beta 2-microglobulin, have been shown to be able to detect amyloid deposits in vivo in a noninvasive manner. At least in the case of labelled beta 2-microglobulin it enables the specific detection of clinically and radiologically unrecognizable AB-amyloid deposits. These tests therefore may have the potential to alleviate the need for biopsy confirmation in the diagnostic workup of a suspected AB-amyloidosis.     

Diagnostic accuracy of subcutaneous abdominal fat tissue aspiration for detecting systemic amyloidosis and its utility in clinical practice

OBJECTIVE: Aspiration of subcutaneous abdominal fat is a simple and fast method for detecting systemic amyloidosis; however, the sensitivity of this approach remains undetermined. The aim of this study was to assess the accuracy of fat tissue aspiration for detecting systemic amyloidosis and the utility of this method in clinical practice. METHODS: All consecutive patients with established and suspected systemic amyloidosis who attended our tertiary referral hospital between 1994 and 2004 underwent aspiration of subcutaneous abdominal fat. Congo red-stained tissue was assessed quickly in a single smear in a routine manner by a single observer, and was also assessed thoroughly in 3 smears by 2 independent observers. RESULTS: One hundred twenty patients with established systemic amyloidosis were studied (38 with AA amyloidosis, 70 with AL amyloidosis, and 12 with ATTR amyloidosis). Routine (quick) assessment was associated with a sensitivity of 80% (95% confidence interval [95% CI] 72-87%). Sensitivity increased to 93% (95% CI 87-97%) when 3 smears were thoroughly examined. The specificity of fat aspiration in 45 control subjects was 100% (95% CI 92-100%). One hundred sixty-two patients for whom there was a clinical suspicion of systemic amyloidosis were screened for amyloidosis by fat tissue aspiration and biopsy of at least 1 other tissue. In 69 (43%) of these 162 patients, a diagnosis of amyloidosis was established, and in 66 (96%) of these patients, the results of fat tissue aspiration were positive. The clinical utility of fat tissue aspiration was greater than that of biopsy of the rectum. CONCLUSION: Subcutaneous abdominal fat aspiration is the preferred method for detecting systemic amyloidosis, with sensitivity of 80% associated with use of a routine approach. The use of a thorough assessment (3 fat smears, 2 observers) increased sensitivity to >90%. If the results of fat tissue aspiration are negative, the additional value of a subsequent biopsy of the rectum is negligible.     

The clinical significance of amyloid fat deposits in rheumatoid arthritis: A systematic long‐term followup study using abdominal fat aspiration

Objective

To analyze the prevalence of subclinical amyloid fat deposits in patients with rheumatoid arthritis (RA) and to evaluate its clinical significance.

Methods

A cohort of 313 adult RA patients were included in this prospective observational study. Systematic abdominal subcutaneous fat aspiration (ASFA) was performed on all patients at study entry. The prevalence of visceral amyloidosis at study entry and at the end of followup was analyzed for patients with a positive ASFA test result. Followup ranged from 1 to 14 years (mean ± SD 6.7 ± 4.1 years). Patients with clinical and subclinical amyloidosis were compared with regard to clinical characteristics and the degree of amyloid deposits in abdominal fat.

Results

The first ASFA test found amyloid in the abdominal fat of 51 patients (16.3%), and subsequent ASFA tests found amyloid in the abdominal fat of 10 additional patients. At the time of the ASFA test, amyloidosis was subclinical in 45 of these 61 patients, 41 of whom were followed up. During followup, 11 of these 41 patients developed renal involvement, 5 due to amyloid nephropathy. Thus, amyloidosis remained subclinical in at least 30 of 41 patients (73%) throughout followup. Marked amyloid fat deposits were found more frequently in patients with clinical amyloidosis than in those whose amyloidosis remained subclinical at the end of followup (57% versus 22%; P = 0.04).

Conclusion

Amyloid fat deposits are not uncommon in adult RA. In the majority of patients, the deposits do not indicate clinically evident organic dysfunction, even after several years of followup. Patients with more extensive fat deposits may have a higher risk of developing clinical amyloidosis.

     

Association of the MCP-1 gene polymorphism A-2518G with carpal-tunnel syndrome in hemodialysis patients.

Carpal-tunnel syndrome (CTS) in long-term hemodialysis patients is caused by the deposition of amyloid as well as by the local inflammatory process. The recruitment of monocytes/macrophages in the tenosynovium, promoted by chemokines such as monocyte chemoattractant protein-1 (MCP-1) and macrophage inflammatory protein-1alpha (MIP-1alpha), is thought to play an important role in CTS development. The genetic polymorphism of these chemokines has been identified and their clinical function has been partly revealed We attempted to analyze the relationship between these polymorphisms and their susceptibility to CTS. The subjects of this study were 366 patients who underwent hemodialysis. Ninety-five patients received surgery for CTS. No significant difference was observed in the genotype distributions of MCP-1 or MIP-1alpha between patients who received CTS surgery and those that did not. However, with the use of a logistic regression model, the MCP-1 GG genotype was identified as a risk factor for the development of CTS, in addition to the duration and the age of initiation of dialysis, as confirmed by a Cox proportional hazards model. In conclusion, homozygosity for G at -2518 in the MCP-1 gene might be a candidate for the genetic marker of CTS development in Japanese hemodialysis patients.     

Association of the MCP-1 gene polymorphism A-2518G with carpal-tunnel syndrome in hemodialysis patients

Abstract

Carpal-tunnel syndrome (CTS) in long-term hemodialysis patients is caused by the deposition of amyloid as well as by the local inflammatory process. The recruitment of monocytes/macrophages in the tenosynovium, promoted by chemokines such as monocyte chemoattractant protein-1 (MCP-1) and macrophage inflammatory protein-1a (M1P-I α), is thought to play an important role in CTS development. The genetic polymorphism of these chemokines has been identified and their clinical function has been partly revealed. We attempted to analyze the relationship between these polymorphisms and their susceptibility to CTS. The subjects of this study were 366 patients who underwent hemodialysis. Ninety-five patients received surgery for CTS. No significant difference was observed in the genotype distributions of MCP-1 or MIP-lα between patients who received CTS surgery and those that did not. However, with the use of a logistic regression model, the MCP-1 GG genotype was identified as a risk factor for the development of CTS, in addition to the duration and the age of initiation of dialysis, as confirmed by a Cox proportional hazards model. In conclusion, homozygosity for G at -2518 in the MCP-1 gene might be a candidate for the genetic marker of CTS development in Japanese hemodialysis patients.     

Diagnostic value of abdominal wall fat pad biopsy in senile systemic amyloidosis

Senile systemic amyloidosis (SSA) is a main cause of intractable heart failure in elderly individuals. To demonstrate transthyretin (TTR)-derived amyloid deposition endomyocardial biopsy has been commonly carried out in the patients with SSA, but this invasive biopsy technique cannot always be performed in aged patients with severe cardiac dysfunction. During the past 3 years, 11 patients with SSA (6 males and 5 females; ages from 70 to 97 years) were examined. All underwent skin biopsy from the abdominal wall and 8 showed TTR-immunoreactive amyloid deposition (sensitivity: 73%): amyloid deposits were seen mainly in the deep layer of subcutaneous fat tissue and showed a patchy distribution. They were weakly Congophilic, but were strongly immunolabeled by an anti-TTR antibody. The severity and pattern of amyloid deposition in this biopsy of SSA patients were considerably different from those obtained from age-matched patients with TTR-related familial amyloid polyneuropathy. Surgical skin biopsy including the deep subcutaneous fat pad can be performed safely at the bedside and is useful for the histopathological diagnosis of SSA.     

A quantitative method for detecting deposits of amyloid A protein in aspirated fat tissue of patients with arthritis

OBJECTIVE—To describe a new, quantitative, and reproducible method for detecting deposits of amyloid A protein in aspirated fat tissue and to compare it with smears stained with Congo red.
METHODS—After extraction of at least 30 mg of abdominal fat tissue in guanidine, the amyloid A protein concentration was measured by a monoclonal antibody-based sandwich ELISA.
RESULTS—The concentrations in 24 patients with arthritis and AA amyloidosis (median 236, range 1.1-8530 ng/mg tissue) were higher (p<0.001) than in non-arthritic controls, uncomplicated rheumatoid arthritis, and other types of systemic amyloidosis (median 1.1, range 1.1-11.6 ng/mg tissue). Patients with extensive deposits, according to Congo red staining, had higher concentrations than patients with minute deposits.
CONCLUSION—This is a new, quantitative, and reproducible method for detecting deposits of amyloid A protein in aspirated fat tissue of patients with arthritis, even when minute deposits are present as detected in smears stained with Congo red.

Keywords: amyloid A protein; fat tissue; arthritis     

Demonstration of protein AA in subcutaneous fat tissue obtained by fine needle biopsy.

Polarisation microscopy of material obtained by fine needle biopsy of subcutaneous tissue and stained with Congo red is a simple and reliable method for the diagnosis of systemic amyloidosis. It cannot, however, be used to differentiate histologically between different forms of amyloidosis. In the present study extracts of material obtained by fine needle biopsy of subcutaneous fat tissue from 13 patients were examined by double immunodiffusion with an antiserum against protein AA, a unique protein which forms a major part of the fibrils in secondary amyloidosis. Five of the patients showed amyloid deposits round the fat cells by conventional microscopy. In 3 of these, all with rheumatoid arthritis, protein AA was detected. Eight patients without amyloidosis and 2 with myelomatosis and amyloidosis showed no reaction with antiprotein AA antiserum. Thus the material obtained by fine needle biopsy of subcutaneous tissue could be used not only for the histological diagnosis of amyloidosis but also for a classification of systemic amyloidosis into secondary or primary based on the type of amyloid fibril protein involved.     

Acute adrenal crisis mimicking familial Mediterranean fever attack in a renal transplant FMF patient with amyloid goiter

The most devastating complication of familial Mediterranean fever (FMF) is amyloidosis which is capable of resulting in chronic renal failure. Although amyloid deposits are frequent in adrenal glands based on the autopsies of FMF patients however; to our knowledge, symptomatic adrenal insufficiency has not been reported yet. We describe a 21-year-old-FMF amyloidosis case with a well-functioning allograft who presented to the emergency clinic with the complaints of abdominal pain, vomiting and diarrhea mimicking FMF attack. adrenocorticotrophic hormone stimulation test was performed due to resistant hyponatremia and disclosed Addison disease. In countries with a high prevalence of FMF, adrenal crisis should be borne in mind in long standing FMF patients.     

Reliable typing of systemic amyloidoses through proteomic analysis of subcutaneous adipose tissue

Considering the important advances in treating specific types of systemic amyloidoses, unequivocal typing of amyloid deposits is now essential. Subcutaneous abdominal fat aspiration is the easiest, most common diagnostic procedure. We developed a novel, automated approach, based on Multidimensional Protein Identification Technology, for typing amyloidosis. Fat aspirates were obtained from patients with the most common systemic amyloidoses (ALλ, ALκ, transthyretin, and reactive amyloidosis), with Congo red score more than or equal to 3+, and nonaffected controls. Peptides from extracted and digested proteins were analyzed by Multidimensional Protein Identification Technology. On semiquantitative differential analysis (patients vs controls) of mass spectrometry data, specific proteins up-represented in patients were identified and used as deposit biomarkers. An algorithm was developed to classify patients according to type and abundance of amyloidogenic proteins in samples; in all cases, proteomic characterization was concordant with fibril identification by immunoelectron microscopy and consistent with clinical presentation. Our approach allows reliable amyloid classification using readily available fat aspirates.     

Arthropathies associated with renal disease including dialysis-related amyloid.

In recent years most of the interest in musculoskeletal problems secondary to renal disease has focused on problems occurring in patients with chronic renal failure and specifically in patients on long-term hemodialysis. The musculoskeletal involvement in long-term hemodialysis may involve the joints, soft tissues, or both, and there is presently no good classification to which authors may refer when they report musculoskeletal problems in these patients. There has been intense interest in the past few years in the amyloidosis associated with long-term hemodialysis, and now, apparently, also with peritoneal dialysis. This type of amyloidosis is due to a specific type of amyloid, namely beta 2-microglobulin amyloid. Debate is ongoing about the role of both aluminum toxicity and iron deposition as cofactors affecting the location and extent of amyloid deposits. Debate is also unresolved about the role of specific dialysis membranes in lessening the incidence of dialysis-related amyloid. I review some of these areas as well as interesting new developments in localization of amyloid deposits in patients with chronic renal failure who are on hemodialysis.     

Clinical picture of the amyloid arthropathy in patients with chronic renal failure maintained on haemodialysis using cellulose membranes.

The clinical picture of 15 patients (10 male, five female) with amyloid arthropathy secondary to chronic renal failure treated with haemodialysis has been studied. The average period of haemodialysis was 10.8 years. Joint symptoms appeared between three and 13 years after starting haemodialysis. No patient had renal amyloidosis. Early symptoms were varied and often overlapped: knee swelling (seven patients), painful and stiff shoulders (seven), and carpal tunnel syndrome (six) were the most prominent. Follow up showed extension to other joints. Joint effusions were generally of the non-inflammatory type. Radiologically, geodes and erosions of variable sizes were seen in the affected joints, which can develop into a destructive arthropathy. Amyloid was found in abdominal fat in three of the 12 patients on whom a needle aspiration was performed. Four of 12 patients showed changes compatible with amyloid infiltration in the echocardiogram. One patient had amyloid in the gastric muscular layer, another in the colon mucus, and two of four in rectal biopsy specimens. Amyloid deposits showed the presence of beta 2 microglobulin in 10 patients. The clinical and radiological picture was similar to the amyloid arthropathy associated with multiple myeloma. These patients can develop systemic amyloidosis.     

Synovial amyloidosis in patients undergoing long-term hemodialysis

Synovial amyloid deposits were found in 18 patients with end-stage renal failure due to various nonamyloid nephropathies, who had been treated with long-term, periodic hemodialysis (mean 116 months). All patients had carpal tunnel syndrome, which was bilateral in 14 of them; 4 patients also had finger flexor tenosynovitis. In 2 patients, destructive arthropathies required surgical replacement of the hip. Amyloid deposits were demonstrated by light microscopy in the synovium of the finger flexor tendon and/or transverse carpal ligament of all patients who had surgery for carpal tunnel syndrome, and in the synovium and capsula of the 2 surgically removed hips. Transmission electron microscopy of synovial samples from 6 patients demonstrated the characteristic fibrillar ultrastructure of amyloid deposits, the biochemical nature of which is still unknown. In addition, 9 patients had cystic radiolucencies of bone, which were interpreted as having resulted from local amyloid deposits, involving carpal bones, humeral heads, femoral heads, acetabula, or tibial plateaus. Our results show that amyloidosis is a frequent histologic finding in dialysis patients receiving surgical management of carpal tunnel syndrome, and that it can also be associated with cystic radiolucencies of bones and with destructive arthropathies.     

Prevalence of secondary amyloidosis in Asian North Indian patients with rheumatoid arthritis

OBJECTIVE: To study the prevalence of secondary amyloidosis in Asian North Indian patients with rheumatoid arthritis (RA) and to determine its clinical significance. METHODS: RA patients with disease duration > 5 years were included in this prospective study over a 2 year period. Abdominal subcutaneous fat pad aspiration (ASFA) was performed, and smears were stained with Congo red and observed for apple-green birefringence under polarized light microscopy. The amyloid deposits were graded from 1+ to 3+. Clinical, radiological, and laboratory variables of the patients were correlated with the presence or absence of amyloidosis. RESULTS: Thirty out of 113 patients were positive for amyloid by ASFA (26.5%). Out of these, 8 patients had features suggestive of clinical amyloidosis in the form of proteinuria, organomegaly, or symptomatic gastrointestinal involvement. In another 22 patients amyloidosis was subclinical. The majority of patients with clinical amyloidosis had either 2+ or 3+ deposits. CONCLUSION: Abdominal fat amyloid deposits are not uncommon in adult Asian North Indian patients with RA. However, only one-fourth of patients had evidence of clinical amyloidosis. A longer followup and a larger multicentric collaborative study is needed to determine the significance of subclinical amyloid deposits.