Correction: Alopecia areata patients show deficiency of FOXP3+CD39+ T regulatory cells and clonotypic restriction of Treg TCRß-chain, which highlights the immunopathological aspect of the disease.

[This corrects the article DOI: 10.1371/journal.pone.0210308.].

Alopecia areata patients show deficiency of FOXP3+CD39+ T regulatory cells and clonotypic restriction of Treg TCRß-chain, which highlights the immunopathological aspect of the disease.

Alopecia areata (AA) is a hair loss disorder resulting from an autoimmune reaction against hair follicles. T-helper 1 cells are a major contributor to this disorder, but little is known about the role of T-regulatory cells (Tregs) in AA. Here, we analysed the distribution of circulating Treg subsets in twenty AA patients with active hair loss and fifteen healthy subjects by flow cytometry. The Treg suppressor HLA-DR+ subpopulation was significantly reduced in the patients (P<0.001) and there were significantly fewer cells expressing CD39 among the CD4+CD25+Foxp3+ Treg subpopulation in patients (P = 0.001). FOXP3 CD39 Treg cells were also reduced in hair follicles; by 75% in non-lesional skin and 90% in lesional skin, when compared to control healthy skin. To further characterise Treg cells in AA; Tregs (CD4+CD25+FOXP3+) were investigated for their TCRß sequence. PCR products analysed by Next Generation Sequencing techniques, showed that all frequent public clonotypes in AA Tregs were also present in controls at relatively similar frequencies, excepting two public clonotypes: CATSRDEGGLDEKLFF (V15 D1 J1-4) and CASRDGTGPSNYGYTF (V2 D1 J1-2), which were exclusively present in controls. This suggests that these Treg clonotypes may have a protective effect and that they may be an exciting subject for future therapeutic applications.

Epigallocatechin-3 Gallate Inhibits STAT-1/JAK2/IRF-1/HLA-DR/HLA-B and Reduces CD8 MKG2D Lymphocytes of Alopecia Areata Patients.

BACKGROUND: Alopecia areata (AA) is associated with Interferon- γ (IFN-γ) mediated T-lymphocyte dysfunction and increased circulating Interleukine-17 (IL-17) levels. Epigallocatechin-3-gallate (EGCG) specifically inhibits IFN-γ pathways and unlike Janus Kinase 1 and 2 (JAK1/JAK2) inhibitors (tofacitinib, ruxolitinib), EGCG is safer, more cost-effective, and is a topically active agent. Our objective is to test the mode of action of EGCG in vitro and ex vivo using HaCat, Jurkat cell lines, and peripheral blood mononuclear cells (PBMCs) of AA patients and healthy controls (HCs), respectively. METHODS: distribution of T helper cells (Th1, Th17), and cytotoxic cells (CD8) in PBMCs isolated from 30 AA patients and 30 HCs was investigated by flowcytomterty. In vitro treatment of HaCat and Jurkat cells with 40 µm EGCG for 48 h was performed to measure the level of phosphorylation of signal transducer and activator of transcription protein STAT1, and replicated in ex vivo model using PBMCs of AA patients. RESULTS: Interestingly, 40 µm EGCG is capable of completely inhibiting phosphorylation of STAT1 after 48 h in HaCat and Jurkat cells and ex vivo in PBMCs of AA patients. Based on QPCR data, the action of EGCG on p-STAT1 seems to be mediated via downregulation of the expression of JAK2 but not JAK1 leading to the inhibition of human leukocyte antigens (HLA-DR and HLA-B) expression probably via IRF-1. On the other hand, AA patients have significantly increased levels of Th1, Th17, and CD8 cells and the production of IFN-γ and IL-17 by PBMCs in AA patients was significantly higher compared to HC; p = 0.008 and p = 0.006, respectively. Total numbers of CD8+ cells were not significantly different between treated and untreated samples. However, CD8+ cells with positive Natural killer group 2 member D (NKG2D) transmembrane receptor (CD8+ NKG2D+ subset) was significantly reduced when PBMCs were treated with 20 µm EGCG for 48 h. CONCLUSION: These results suggest that EGCG has a synergistic action that inhibits expression of HLA-DR and HLA-B molecules via the IFN-γ pathway to maintain immune privilege in HF; also it reduces CD8+ NKG2D+ subset.