Immunohistochemical assessment of SOX10 and its relation to the immune cellular infiltrate in alopecia areata follicles

Background Alopecia areata (AA) is a nonscarring patchy hair loss that can extend to affect all body hair. Many hypotheses for autoimmunity onset in AA have been reported and the immune privilege collapse theory is the most accepted. Objective To evaluate the immunohistochemical expression of SOX10 within the AA hair follicles as one of the melanocytic markers as well as its relation to the inflammatory infiltrate. Patients and methods The current observational descriptive hospital-based cross-sectional pilot study included 16 patients with AA. Skin biopsies were taken from the border of the alopecic patch, and cross-sectioned hair follicles were examined by H and E and SOX10 immunostaining after assessing activity using a hair pull test. Follicles in cut sections were numbered and evaluated for the presence as well as the density of perifollicular lymphocytic infiltrate. Moreover, counting of SOX10+ cells was performed for the immunostained sections. Results The study included 16 patients with AA, six (37.5%) males and 10 (62.5%) females, ranging in age from 5 to 40 years (median = 18.5, IQR = 9.5–27). Based on the hair pull test, nine (556.3%) patients had active disease, while seven (43.8%) patients were apparently stable. Within the 81 examined AA follicles, 53 showed SOX10+ expression that showed a significant positive relation with the inflammatory infiltrate ( P =0.001). Conclusion SOX10 is clearly expressed in the hair follicles of AA and is significantly related to the mononuclear infiltrates that accompany the pathogenesis of the disease. Therefore, melanocytes may carry the antigenic epitope required to initiate the organ-specific autoimmunity in AA, and this may explain the regrowth of only white hair follicles in some cases of AA.