CS and rheumatoid arthritis: In the RA patient subset, anti-CS IgM levels did not change after 6 months (495.1 ± 381.7 units; p = 0.184); however, they significantly increased by 12 months (545.8 ± 335.1 units; p = 0.002) versus baseline (421.7 ± 244.9 units).