Changes and significance of Th1/Th2 and Treg/Th17 cells and their cytokines in patients with alopecia areata

Background

Alopecia areata (AA) is a chronic autoimmune disease. Th1/Th2 and Treg/Th17 cells and their cytokines are implicated in AA, and we explored their clinical significance in AA.

Methods

AA patients and healthy people (controls) were enrolled, with their Th1/Th2/Th17/Treg cell proportion changes and serum Th1 (INF-γ)/Th2 (IL-5, IL-6)/Th17 (IL-17, IL-22)/Treg (IL-35) cytokine levels assessed. AA patients were assigned into mild, moderate and severe alopecia according to Severity of Alopecia Tool (SALT). The relationship between alopecia severity and initial onset age, disease course, family/smoking/drinking history and sleep disorders was explored. Th1/Th2 and Treg/Th17 cells and their cytokine levels in AA patients with different severity levels were compared. The correlation between cytokine levels and SALT scores was analyzed using Spearman. Additionally, the changes of serum cytokine levels in inactive/active AA patients were compared.

Results

AA patients differed from controls in family history/smoking history/drinking history/sleep disorders. Peripheral blood Th1/Th2/Th17 cell proportions and INF-γ/IL-5/IL-6/IL-17/IL-22 levels increased, while Treg cell proportions and IL-35 level dropped. With higher alopecia severity, the proportions of Th1, Th2 and Th17 cells increased, and Treg cell proportion decreased. AA patients with mild/moderate alopecia had significant differences in IL-17 level. Serum INF-γ, IL-5, IL-17 and IL-22 levels were elevated, and IL-35 level dropped in severe AA patients versus moderate AA patients.

Conclusion

Th1/Th2/Th17 cell proportions and serum INF-γ/IL-5/IL-6/IL-17/IL-22 levels in AA patients were up-regulated, while Treg cell proportion and IL-35 level were repressed. SALT scores were positively-correlated with serum IL-5/IL-17 levels. SALT scores were negatively-correlated with serum IL-35.