Assessment of interleukin-17 in alopecia areata: a case–control pilot study

Background Alopecia areata (AA) is an autoimmune disease mediated mainly by CD8+ T cells; however, CD4+ T cells provide help. Interleukin (IL)-17 is a key cytokine produced by T helper 17 cells (a subset of CD4+ T cells), which plays a role in autoimmune diseases. Objective The objective of this study was to provide more insight into the role of IL-17 in the etiopathogenesis of AA. Patients and methods The study was carried out on 18 patients with different clinical types of AA and 20 agematched and sex-matched controls. Skin biopsies were subjected to enzyme-linked immunosorbent assay and reverse transcriptase-PCR for measurement of tissue levels of IL-17 and its mRNA expression. Results Both IL-17 and its mRNA expression were significantly higher in AA lesions compared with controls (Po0.0001) and were significantly higher in cases of alopecia totalis compared with alopecia universalis and patchy AA (Po0.0001). A strong significant positive correlation existed between IL-17 and its mRNA. Conclusion IL-17 appears to be involved in autoimmune inflammation in AA. Therapeutic targeting of IL-17 may provide a potential therapeutic option in this chronic autoimmune disease.