Serum granulysin as a possible key marker of the activity of alopecia areata

Background: Alopecia areata (AA) is an organ-restricted autoimmune condition of the hair follicles (HFs) that presents as nonscarring hair loss. A collapse of immunoprivilege for cell-mediated cytotoxicity and following attacks by cytotoxic T cells to anagen HFs are considered to play a major role in the pathogenesis of AA. However, there has been no useful marker for the activity of AA to date. Objective: The aim of this study is to examine whether granulysin, which is known to reflect the activity of cytotoxic immune responses, is related to the disease activity of AA. Methods: We evaluated serum granulysin levels in acute and chronic AA patients compared to healthy controls in the perspective of bald skin areas, prognosis, and co-existence of other allergic diseases. In addition, immunohistochemical analysis for granulysin-, CD4-, CD8-, and CD56-positive cells in the lesional skin of acute and chronic AA patients was performed. Results: Serum granulysin levels were significantly elevated in both acute and chronic AA patients (p = 0.00081 and p = 0.0012, respectively). Intriguingly, serum granulysin levels were significantly associated with the broader bald skin areas (Spearman's r = 0.59, p = 0.017), and poorer prognosis in acute AA patients (p = 0.0080). They were also associated with co-existence of allergic disorders in AA patients (p = 0.026). Immunohistochemical staining demonstrated that perifollicular granulysin-bearing cells were mainly detected in acute AA lesions with dense lymphocytic infiltration, and that these granulysin-bearing cells were consistent with CD8(+) T cells. Conclusion: The serum granulysin level may be a useful and novel marker for the disease activity in the acute phase of AA. (C) 2013 Japanese Society for Investigative Dermatology. Published by Elsevier Ireland Ltd. All rights reserved.