The Role of T-Helper 17 Cells and Regulatory T Cells in Acute Diffuse and Total Alopecia: The Increased Function of Regulatory T Cells May Explain the Favorable Prognosis.

BACKGROUND

Acute diffuse and total alopecia (ADTA) is a variant of alopecia areata (AA) that lacks the typical patchy hair loss seen in classical AA and presents with an acute onset of diffuse hair loss. It has a favorable prognosis.

OBJECTIVES

The purpose of this study was to assess the role of T-helper (Th) 17 cells and regulatory T cells (Tregs) in the pathogenesis of ADTA and their relevance to the good prognosis of ADTA.

METHODS

Twenty-four patients with ADTA and 12 healthy controls were included. Scalp skin samples were obtained for quantitative polymerase chain reaction (qPCR) specific for Th17 cells and Treg-related cytokines. Serum cytokines associated with Th17 cells and Tregs were measured using enzyme-linked immunosorbent assays. Additionally, we performed immunostaining for Th17 cells and Tregs. The correlation of qPCR results, serum cytokine levels, and immunostaining results with clinical characteristics was examined.

RESULTS

Lesional IL-2, IL-10, and IL-23A levels were significantly higher in patients with ADTA than in controls. In the progressive stage, lesional IL-2, IL-13, and IL-23A levels were significantly increased compared to those in controls. Serum IL-15 levels were significantly lower in patients than in controls in the progressive stage. In the recovery stage, lesional IL-13 and IL-23A levels were significantly increased compared to those in controls. The ratios of Th17/CD4+ cells and Tregs/CD4+ cells surrounding hair follicles of the patients were 40.73% and 8.50%, respectively, according to immunostaining results.

CONCLUSIONS

The increased activity of Treg cells, suggested through IL-10 and IL-15, is a characteristic of ADTA that is distinct from AA. The increased function of Tregs may explain the favorable prognosis of ADTA. Follow-up studies focusing on Tregs, IL-10, and IL-15 are required.