CALR and rheumatoid arthritis: Positive results in the investigation of RA factor were observed in 65.9% (191) of the patients, anti-CCP in 37.9% (110), ANA in 31.4% (91), anti-dsDNA in 18.6% (54), anti-Sm in 10% (29), anti-RNP in 6.6% (19), and anti-Ro in 6.2% (18) of the patients.