 IL-6 blocking therapy significantly reduces signs and symptoms as well as radiological progression in RA. However, so far, it has not been determined which of the pleiotropic IL-6 effects impact the observed clinical response. Recently, Samson et al have demonstrated that Tocilizumab TCZ corrects the imbalance between Th17 cells and Treg cells in patients with RA. More interestingly, the group of Hans-Peter Tony has reported the impact of TCZ on B cell compartment. They showed a significant reduction in the frequency of peripheral pre-switch and post-switch memory B cells but also a reduction of serum immunoglobulin levels, that could be the reflect of TCZ on Tfh cells development, circulation andor function. 