Our findings confirm the results of previous reports [23,33] and extend them by showing that constitutive STAT3 phosphorylation of CD4+ T cells identifies a subgroup of RA patients characterized by high disease activity, as determined by DAS28, presence of systemic inflammation, as determined by plasma CRP level, and good EULAR response to treatment with DMARDs. This evidence concerns the gene STAT3 and rheumatoid arthritis.