Follicular helper T cells and fibrotic diseases.

T follicular helper (Tfh) cells constitute a functionally specialized subset of CD4+ T lymphocytes that orchestrate germinal center (GC) responses, critically regulating B cell destination and the development of long-term humoral immunity. Emerging evidence implicates Tfh cells as key mediators in the pathogenesis of multiple fibrotic disorders across multiple organ systems, including systemic sclerosis (SSc), hepatic fibrosis, chronic kidney disease, idiopathic pulmonary fibrosis (IPF) and IgG4-Related Disease (IgG4-RD). This review synthesizes current understanding of Tfh cell biology in fibrosis, aiming to provide deeper insights into their involvement in pathogenesis and identify potential new therapeutic targets.