TFRC and B-cell chronic lymphocytic leukemia: The so-called non-Treg cell population is thus probably best understood in the context of CLL as a heterogeneous group of cells in the peripheral circulation containing not only cells without suppressor function and with the ability to produce proinflammatory cytokines (IL-17 and IFN-g), but also circulating CXCR5+ T regulatory follicular cells (Tfr), perhaps reflecting the continuous production of (auto)antibodies [44].