CD4 and rheumatoid arthritis: With the exception of effector Treg cells (CD4+CD45RA-CD25+CD127-), total Treg cells, naïve Treg cells, and activated CD4+T cells all differed significantly between RA patients and healthy controls, which expands the findings of previous studies (Kawashiri et al., 2011; Walter et al., 2013; Walter et al., 2016).