Regulatory T Cells in Autoimmune Skin Diseases

The 2018 review article examined the involvement of CD4*Foxp3* regulatory T cells (Tregs) in various autoimmune skin diseases, such as alopecia areata, vitiligo, pemphigoid, pemphigus, systemic sclerosis, morphoea, and psoriasis. It was found that Treg dysfunction is implicated in these conditions, with altered frequency and function of Tregs being a common theme. For instance, in alopecia areata, treatments that increased Treg numbers led to partial hair regrowth, and in vitiligo, strategies that increased Treg numbers resulted in remission. The role of Tregs in pemphigoid and pemphigus is less clear, but there is evidence suggesting Tregs may suppress autoantibody production. In systemic sclerosis, both increases and decreases in Treg frequency have been observed, and TGF-B produced by Tregs may have harmful effects. The review also noted the importance of considering Treg subpopulations, the impact of age on Treg populations, and the differences between skin-resident Tregs and those in blood and lymphoid organs. It highlighted the technical challenges in studying Tregs, such as the need for antigen-specific stimulation in suppression assays and the complexity of identifying Tregs in human skin. The document concluded that a better understanding of Treg properties is crucial for developing new treatments for autoimmune skin diseases and that further research is needed to clarify the inconsistencies in Treg-related findings due to methodological variations, subject age, and disease stages.