Follicular helper T cells in type 1 diabetes.

Type 1 diabetes (T1D) is an autoimmune disease caused by the dysfunction of immune system and consequently the destruction of insulin-producing β cells. In past decades, numerous studies have uncovered that CD4+ T cell subsets are critical in the pathogenesis of T1D, manifesting that type 1 T helper (Th1) and Th17 cells are pathogenic, while regulatory T (Treg) cells and Th2 cells are protective. More recently, the pathogenic role of another subset, follicular helper T (Tfh) cells that essentially regulate germinal center (GC) formation and humoral responses, has also been demonstrated in T1D and many other autoimmune diseases. In this review, we summarize the evidence for the aberrant differentiation and function of Tfh cells in T1D, and also discuss the underlying mechanisms. A better understanding on the pathogenic role of Tfh cells in T1D will inspire the design of potential therapeutic strategies to target this subset in the future.