PT - JOURNAL ARTICLE AU - Shuichiro Nakabo AU - Hajime Yoshifuji AU - Motomu Hashimoto AU - Yoshitaka Imura AU - Ran Nakashima AU - Kosaku Murakami AU - Nobuo Kuramoto AU - Shinji Ito AU - Junko Satoh AU - Masao Tanaka AU - Takao Fujii AU - Tsuneyo Mimori AU - Koichiro Ohmura TI - Anti-carbamylated Protein Antibodies Are Detectable in Various Connective Tissue Diseases AID - 10.3899/jrheum.161432 DP - 2017 May 15 TA - The Journal of Rheumatology PG - jrheum.161432 4099 - http://www.jrheum.org/content/early/2017/05/09/jrheum.161432.short 4100 - http://www.jrheum.org/content/early/2017/05/09/jrheum.161432.full AB - Objective Anti-carbamylated protein (anti-CarP) antibodies are possible diagnostic biomarkers of anticitrullinated protein antibody (ACPA)-negative rheumatoid arthritis (RA). We aimed to elucidate the prevalence of anti-CarP antibodies in non-RA connective tissue diseases (CTD) because CTD are important in the differential diagnosis of ACPA-negative RA. Methods The sera from 266 patients with RA and 616 patients with CTD and 80 healthy controls were examined using an in-house anti-CarP ELISA. Results The prevalence and the level of anti-CarP antibodies in several CTD were comparable to those in ACPA-negative RA. Conclusion Anti-CarP antibodies are not useful for differentiating ACPA-negative RA from CTD.