To extend these findings and identify a CD4+ T cell subset most “sensitive” to circulating cytokine, we first compared constitutive pSTAT3 levels in true naïve (TN), central memory (CM), and effector memory (EM) CD4+ T cells [denoted CD45RA+ CD62L+, CD45RA- CD62L+ and CD45RA- CD62L-, respectively (21)] in the same cohort of early arthritis patients (3). Here, CD4 is linked to Arthritis.