Topical immunotherapy treatment of alopecia areata with diphenylcyclopropenone: Regulatory T cells as biomarkers for treatment response.

Treatment of alopecia areata is often challenging, especially for patients with extended disease. Contact immunotherapy with diphenylcyclopropenone (DPCP) has been reported as an effective topical treatment but the exact immunologic mechanism of diverting the immune response is still unknown. We investigated the efficacy of topical immunotherapy with DPCD in acute, intermediate, and chronic lesions of AA and the response rate was associated with perifollicular infiltrate of T regulatory cells. Approximately two-thirds of our patients (67.5%) had a response rate > 50% after 6 months of DPCP therapy. Patients with acute and intermediate onset of the disease were more likely to respond to the therapy. Although responders demonstrated FOXP3+ positive lymphocytes in immunohistochemistry, this association could not be confirmed by statistical significance (p = 0.052). In patients with multiple lesions, that had different chronological onset, the lesions with more recent onset responded faster than lesions of longer duration.