1965: Autoantibodies Against a Specific 25-mer Peptide from P. Gingivalis Are Present in Sera of Patients with Rheumatoid Arthritis and Early Arthritis

Hsin-Yi Peng¹, Ting-Yin Xue¹, Fei-Hung Hsieh¹, Yi-Ko Chen¹, Mei-Chin Yin², Che-Yi Chao², Shu-Yao Tsai², Chung-Ping Lin³, Po-Hao Huang³, Chien-Chung Huang³, Jiunn-Horng Chen³, Chung-Ming Huang³, Der-Yuan Chen⁴, Joung-Liang Lan⁵ and Gregory Tsay³, ¹China Medical University, Taichung, Taiwan, ²Asia University, Taichung, Taiwan, ³China Medical University Hospital, Taichung, Taiwan, ⁴China Medical University Hospital Rheumatology and Immunology Center, Taichung, Taiwan, ⁵China Medoical University Hospital, Taichung, Taiwan

Background/Purpose: The presence of rheumatoid factor (RF) or anti-cyclic citrullinated protein/peptide antibodies (ACPA) are included in the 2010 the ACR/EULAR classification criteria of rheumatoid arthritis (RA). But the prevalence of RF and ACPA in the RA population was lower than 60%. The development of a new detection assay with increasing the sensitivity for the diagnosis of RA is needed.

Methods: A 25-peptide named BR1 from the cysteine protease of Porphyromonas gingivalis was synthesized for the study. Serum samples from patients with RA, early arthritis, other rheumatic diseases, and normal controls were used in the study. The anti-peptide antibodies were detected by ELISA.

Results: Anti-BR1 were detected in 56.0% (59/106) of RA patients and were found in 63.8% (23/36) of RA patients without both RF and/or ACPA. The serological positive rates with the two tests of RF and ACPA and with the three tests of anti-BR1, RF, and ACPA were 66% and 84.2%, respectively. The positive rates Anti-BR1 were detected in 60.0% (9/15) of patients with early arthritis, but neither RF nor ACPA was detected in this group of patients. The sensitivity and specificity for RA were 60.1% and 95%, respectively.

Conclusion: A specific 25-mer peptide from the cysteine protease of P. gingivalis is the epitope for humoral immune response in rheumatoid arthritis. The anti-25-mer peptide antibody test is an excellent new test for the diagnosis of patients with RA and early arthritis.

Disclosures: H. Peng, None; T. Xue, None; F. Hsieh, None; Y. Chen, None; M. Yin, None; C. Chao, None; S. Tsai, None; C. Lin, None; P. Huang, None; C. Huang, None; J. Chen, None; C. Huang, None; D. Chen, None; J. Lan, None; G. Tsay, None.