Folliculotropic Mycosis Fungoides with Skewed T-Cell Receptor CDR3 Motif: Suggestive of Lipid-Antigen Selection?

The study investigated folliculotropic mycosis fungoides (FMF), a variant of mycosis fungoides characterized by malignant T cell infiltration in hair follicles, in 21 patients with FMF and 20 control patients with MF. It found a recurrent usage of TRB junctional genes TRBJ2-1 and TRBJ2-7 in FMF patients, contributing to an amino acid motif in the T-cell receptor's complementarity-determining region 3 (CDR3). This motif was previously associated with T cells stimulated by lipids bound to CD1 on antigen-presenting cells. Immunohistochemical analysis showed abundant CD1c- and CD1a-expressing dendritic cells in FMF, supporting the hypothesis that lipid-antigen stimulation played a role in FMF pathogenesis.