Identification of human hair follicle antigens targeted in the presumptive autoimmune hair follicle disorder alopecia areata and their potential functional relevance in vitro : methods development for isolation and identification of alopecia areata-relevant human hair follicle antigens using a proteomics approach and their functional assessment using an ex vivo hair follicle organ culture model

This study investigated the autoimmune basis of alopecia areata (AA) by identifying hair follicle antigens targeted by antibodies in AA patients. Using serum antibodies from 10 AA patients and 10 controls, researchers identified trichohyalin and keratin 16 as potential target antigens through mass spectrometry. Trichohyalin was immunoprecipitated by all AA sera and only 5 normal sera, with significantly higher Mascot scores in the AA group (p=0.005). Functional studies showed that antibodies to these proteins inhibited hair fibre elongation in ex vivo cultures. Indirect immunofluorescence indicated higher immunoreactivity in AA sera against anagen hair follicles, particularly in the outer and inner root sheaths. The findings suggested an antibody response to anagen-specific hair follicle antigens in AA, potentially playing a pathogenic role.