Session Information
Session Type: ACR Poster Session C
Session Time: 9:00AM-11:00AM
Background/Purpose: Rheumatoid arthritis (RA) diagnosis includes determination of autoantibodies and, their presence can represents 33% (2/6) to 50% (3/6) of the 2010 ACR/EULAR classification criteria [1]. Rheumatoid factor has three isotypes, of which IgM is the most used because of its sensitivity and specificity [2]. The aim of this study is to evaluate the performance of RF isotypes alone and in combination with anti-cyclic citrullinated peptide (anti-CCP) antibodies in the RA diagnosis.
Methods: An observational, retrospective and analytical study was made. We selected all results of RF and anti-CCP sent to our laboratory between March 2014 and March 2015 with an inflammatory arthritis suspicion. We collected final diagnosis according to medical records and classified patients with RA (2010 ACR-EULAR), Osteoarthritis (OA, ACR), Systemic lupus erythematosus (SLE,1987 ACR criteria) and Primary Sjögren syndrome (pSS, 2012 American-European-Consensus-Group (CETA) criteria). RF isotypes evaluated was IgA, IgM and IgG measured by ELISA (ORGENTEC®) with a cut-off > 20 IU and anti-CCP2 antibodies by ELISA (ORGENTEC®) with a cut-off> 25 IU. We made a descriptive analysis of the seropositivity according to different diseases. Then, we performed an analysis of sensitivity and specificity using autoantibodies alone and in different combinations for the final RA diagnosis.
Results: We included 62 (44.3%) RA patients, 10 (7.1%) patients with SS, 5 (3.5%) patients with SLE, and 52 (37.1%) patients with OA. In table 1 we described autoantibodies frequencies according to different diseases. Sensitivity and specificity to RA diagnosis was represented in Table 2 with autoantibodies combinations.
Conclusion: The combination of the four autoantibodies increased sensitivity for RA detection, although we observed a decreased of global specificity of the test.
References: 1.Aletaha D, Neogi T, Silman AJ, et al. Arthritis Rheum 2010;62:2569-81. 2. Sun J, Zhang Y, Liu L, et al. Clin Exp Rheumatol 2014;32:11-21
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Table 1. Frequencies of autoantibodies according different diseases
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RA: Rheumatoid Arthritis, OA: Osteoarthritis, pSS: Primary Sjögren Syndrome, SLE: Systemic Lupus Erythematosus. RF: Rheumatoid Factor, anti-CCP: anti-Cyclic Citrullinated Peptide antibodies |
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Table 2. Sensitivity and specificity according to autoantibodies and their combinations for RA detection
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RF: rheumatoid factor, Anti-CCP: anti-cyclic citrullinated peptide antibodies |
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To cite this abstract in AMA style:
Garza-Alpirez A, Garza-Elizondo MA, Vega-Morales D, Skinner-Taylor C, Ramírez R, Negrete-López R, Esquivel-Valerio J, Villarreal-Alarcon M, Mendiola A. Is It Useful to Determine All Rheumatoid Factors Isotypes to Enhance Rheumatoid Arthritis Detection? a Clinical Laboratory Perspective [abstract]. Arthritis Rheumatol. 2015; 67 (suppl 10). https://acrabstracts.org/abstract/is-it-useful-to-determine-all-rheumatoid-factors-isotypes-to-enhance-rheumatoid-arthritis-detection-a-clinical-laboratory-perspective/. Accessed .« Back to 2015 ACR/ARHP Annual Meeting
ACR Meeting Abstracts - https://acrabstracts.org/abstract/is-it-useful-to-determine-all-rheumatoid-factors-isotypes-to-enhance-rheumatoid-arthritis-detection-a-clinical-laboratory-perspective/