Pathophysiology of T follicular helper cells in humans and mice

Follicular helper T cells (T_FH cells) compose a heterogeneous subset of CD4 + T cells that induce the differentiation of B cells into plasma cells and memory cells. They are found within and in proximity to germinal centers in secondary lymphoid organs, and their memory compartment also circulates in the blood. Our knowledge on the biology of T_FH cells has increased significantly during the past decade, largely as a result of mouse studies. However, recent studies on human T_FH cells isolated from lymphoid organ and blood samples and recent observations on the developmental mechanism of human T_FH cells have revealed both similarities and differences between human and mouse T_FH cells. Here we present the similarities and differences between mouse and human lymphoid organ-resident T_FH cells and discuss the role of T_FH cells in response to vaccines and in disease pathogenesis.