Target tissue ectoenzyme CD39/CD73-expressing Foxp3+ regulatory T cells in patients with psoriasis.

Summary Background Psoriasis is a chronic, relapsing, inflammatory skin disease, in which regulatory T cells (Tregs) play an important role. Recently, human Treg ectoenzymes (CD39/CD73) have been reported to mediate the suppressive activity of Tregs. Aim To investigate the proportions of CD39/CD73 expressing Foxp3+ regulatory T cells in different types of psoriatic lesions. Methods Immunohistochemical staining was used to analyse expression of Foxp3, CD39 and CD73 in biopsy tissue from healthy controls and from patients with different types of psoriasis. Results In normal control biopsies, CD39+ cells were scattered throughout the epidermis and dermis, while CD73+ cells were localized predominantly in the dermis. The proportion of cells that were both CD39+ and Foxp3+ was significantly lower in pustular psoriasis (PP) and erythrodermic psoriasis (EP) than in psoriasis vulgaris (PV) (25.0 ± 2.6%, 26.5 ± 2.0% and 45.1 ± 3.5%, respectively; P < 0.001). Likewise, CD73+Foxp3+ cells were lower in PP and EP than in PV (6.2 ± 1.9%, 11.6 ± 2.8% and 17.7 ± 2.3% respectively, P < 0.001). There were no significant differences in the population size of double-staining cells in EP compared with PP. Conclusion The relative reduced expressions of CD39 and CD73 within Foxp3+ Tregs may imply a different immunopathogenesis for different psoriatic lesions.