Understanding the development and function of T follicular helper cells

A fundamental function of T helper (Th) cells is to regulate B-cell proliferationand immunoglobulin class switching, especially in the germinal centers. Th1 andTh2 lineages of CD4⁺ T cells have long been considered to playan essential role in helping B cells by promoting the production immunoglobulinG2a (IgG2a) and IgG1/IgE, respectively. Recently, it has become clear that asubset CD4⁺ T cells, named T follicular helper (Tfh) cells, iscritical to B-cell response induction. In this review, we summarize the latestadvances in our understanding of the regulation of Tfh cell differentiation, therelationship of Tfh cells to other CD4⁺ T-cell lineages, and therole of Tfh cells in health and disease.