Identification of Post-Translationally Modified Trichohyalin Epitopes Responsible for Triggering Autoimmunity in Alopecia Areata

This study investigated the role of trichohyalin (TCHH) as a potential autoantigen in alopecia areata (AA) by identifying post-translationally modified immunoreactive TCHH epitopes. Researchers found that TCHH undergoes significant citrullination during the anagen phase, a modification implicated in autoimmune disorders. Using ultrastructural TEM immuno-gold analysis, mass-spectrometric, and in-silico analyses, they identified several citrullinated residues within TCHH that are immunologically relevant. Six putative antigenic peptides with citrullinated residues were synthesized and tested for cell-mediated and humoral autoreactivity using ELISpot and ELISA assays. The study concluded that TCHH epitopes, located in the peripheral region of the anagen hair bulb, are accessible to immune cells and may trigger the immune-mediated attack in AA.