Flow cytometric analyses of circulating regulatory T cells in patients with dermatitis herpetiformis and other immune mediated dermatoses.

Regulatory T cells (Tregs) play a crucial role by maintaining the peripheral tolerance and inhibiting autoimmunity. In recent years, numerous autoimmune and immune-mediated diseases have been shown to present significant number depletion and/or function impairment of this subset. In the present study, we present a brief overview of the results obtained by our group in association with the centers belonging to the Italian Immunopathology Group, as to the expression levels and biological significance of circulating regulatory CD4+CD25+brightFOXP3+ T cells in a variety of immune-mediated skin diseases (such as psoriasis, scleroderma, bullous pemphigoid and GvHD), together with preliminary results achieved in patients with inflammatory bowel disease-related dermatoses. This review shows that this series of different cutaneous diseases characterised by an immune-mediated pathogenesis, share a significant down-regulation of circulating FOXP3+ Treg cells, whilst the treatment and the achievement of clinical response are generally associated with an opposite phenomenon with up-regulation of Treg cells. Future studies are mandatory to identify the effective role of these modifications in the disease pathogenesis as well as its relationship with the clinical response.