IL17A and relapsing-remitting multiple sclerosis: Consistently with the role of IL-6 in regulating IL-17A expression (54) and with our previous data in RRMS patients (37), the blockade of IL-6-mediated signaling by a neutralizing anti-IL6 Ab strongly inhibited (at least 70%) CD28-induced IL-17A expression in CD4+ T cells from HD (Figure 2F).