Imbalance of circulating CD4(+)CXCR5(+)FOXP3(+) Tfr-like cells and CD4(+)CXCR5(+)FOXP3(-) Tfh-like cells in myasthenia gravis.

Follicular regulatory T (Tfr) cells are defined as a specialized subset of regulatory T cells (Tregs) that act to control the overactivation of follicular helper T (Tfh) cells and B cells in germinal centers. Accumulating evidence has demonstrated that the dysregulation of either Tfr cells or Tfh cells results in abnormal germinal center responses that contribute to the pathogenesis of autoimmune diseases. However, the role that Tfr cells and Tfh cells play in myasthenia gravis (MG) remains unclear. This study revealed a significantly decreased frequency of CD4(+)CXCR5(+)FOXP3(+) Tfr-like cells and an increased frequency of CD4(+)CXCR5(+)FOXP3(-) Tfh-like cells in the peripheral blood of MG patients compared with healthy controls. Moreover, the Tfr-like/Tfh-like ratio was inversely correlated with the clinical severity of the MG patients. Interestingly, glucocorticoid (GC) treatment can restore the imbalance of circulating Tfr-like/Tfh-like cells, and this restoration is accompanied by reduced clinical symptoms. These results suggested, for the first time, that an imbalance of circulating Tfr-like and Tfh-like cells may be involved in the immunopathogenesis of MG and may provide novel insight for the development of MG therapies.