Abstract: Objective: To analyze the expression of 12 cytokines related to Th1/Th2/Th17/Treg in the peripheral blood of patients with alopecia areata and their correlation with the severity, activity, and course of alopecia areata, and to explore their clinical value in the pathogenesis of alopecia areata. Methods: The levels of Th1, Th2, Th17, and Treg cytokines in the peripheral blood of 193 patients with alopecia areata who were retrospectively collected, including the expression levels of IL-1β, IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, IL-12p70, IL-17, IFN-α, IFN-γ, and TNF-α. According to the Severity of Alopecia areata Tool (SALT), patients with alopecia areata were divided into mild, moderate, and severe, and the clinical value of peripheral blood cytokine changes in alopecia areata was discussed, and the correlation between different severity, active and stable period, disease course ＜ 6 months and ≥ 6 months and serum cytokine levels were statistically analyzed. Results: Among the 12 cytokines detected, the concentrations of four cytokines, IL-2, IL-5, IL-6, and IL-17, were significantly increased, and the expression level of IL-6 in patients with active alopecia areata was significantly higher than that in patients with a stable stage, and the difference was statistically significant (P＜0.05). IL-6 was positively correlated with disease activity (r=0.19, P＜0.05). The concentrations of IL-2, IL-5, and IL-17 in patients with alopecia areata were significantly lower than those before treatment (all P＜0.05). Conclusion: The serum IL-6 level in patients with active alopecia areata is significantly elevated and positively correlated with disease activity, suggesting that IL-6 can be used as a potential marker for assessing disease activity. The upregulation of serum IL-2, IL-5, IL-6 and IL-17 levels in patients confirms that the imbalance of the Th17 and Treg cytokine network is involved in the pathogenesis and clinical progression of alopecia areata.

Key words: alopecia areata, cytokines, interleukin