TFRC and rheumatoid arthritis: Moreover, in the present study, disease activity indicators (ESR, CRP, DAS28), immunoglobulins (IgA, IgM, IgG), and typical antibodies of RA (anti-CCP, RF, AKA, APF) were not significantly correlated with Tfr-like, Tfh-like, or Tfh-like cell subsets.