Tfh Cells in Henoch-Schönlein Purpura (IgA Vasculitis): Current Concept

Henoch-Schönlein purpura (HSP) is an inflammatory condition affecting the small blood vessels, leading to organ damage and symptoms across various body systems, including skin, joints, and kidneys. The disease's pathogenesis involves the deposition of immunoglobulin (Ig) A immune complexes in vessels, triggering inflammation and damage. Recent research highlights the role of T follicular helper cells (Tfh cells) in HSP. The review delves into Tfh cells' biological functions, emphasizing their involvement in the HSP's development by activating autoreactive B cells and inducing the production of autoantibodies through the secretion of interleukin (IL)-21, IL-4, and IL-6. Additionally, the roles of different Tfh cell subsets in the pathogenesis of HSP are also characterized by their unique features. We also highlight the relationship between Tfh cells and galactose-deficient IgA1 (Gd-IgA1) production, compare Tfh-mediated immune responses in HSP with those in IgA nephropathy (IgAN) and systemic lupus erythematosus (SLE), and discuss emerging therapeutic strategies targeting the Tfh-B-cell axis. It concludes by suggesting the need for further research on Tfh cells to understand HSP pathogenesis better and develop effective treatments.