The effect of interleukin (IL)-21 and CD4 CD25 T cells on cytokine production of CD4 responder T cells in patients with myasthenia gravis.

Impairment of the suppressive function of regulatory T (T ) cells has been reported in myasthenia gravis (MG). In this study, cytokine-related mechanisms that may lead to the defect of T were investigated in patients with anti-acetylcholine receptor antibody-positive MG (AChR + MG). Proliferation and cytokine production of responder T (T ) cells in response to polyclonal activation were measured in a suppression assay. The effect of interleukin (IL)-21 on suppression was evaluated in vitro in co-culture. IL-21 increased the proliferation of T cells in T /T co-cultures. T cells from patients with MG secreted significantly lower levels of IL-2. In patients with MG, IL-2 levels did not change with the addition of T to cultures, whereas it decreased significantly in controls. In T /T co-cultures, IL-4, IL-6 and IL-10 production increased in the presence of T in patients. Interferon (IFN)-γ was decreased, whereas IL-17A was increased in both patient and control groups. IL-21 inhibited the secretion of IL-4 in MG and healthy controls (HC), and IL-17A in HC only. The results demonstrated that IL-21 enhances the proliferation of T cells in the presence of T . An effect of IL-21 mainly on T cells through IL-2 is implicated.