Strikingly, Anderson et al. detected a STAT3 target gene signature with aberrant expression, including that of SOCS3, PIM-1, and Bcl-3, in CD4+ T cells from RA patients.12 These molecules were also among the most highly expressed genes and part of a discriminatory gene signature in CD4+ T cells from tuberculosis patients.13 Here, CD4 is linked to rheumatoid arthritis.