Characterization of regulatory T cells in patients with dermatomyositis

The purpose of this study was to characterize regulatory T cells (T-reg) in skin lesions and peripheral blood from patients with dermatomyositis (DM) and to determine the serum levels of regulatory cytokines in the disease In skin biopsy specimens from patients with DM immunohistochemistry was performed for CD4(+) CD25(+) forkhead/winged helix transcription factor (FoxP3)(+) transforming growth factor (TGF)-beta(+) and interleukin (IL)-10(+) cells Additionally we defined the number of T g subpopulations in peripheral blood by flow cytometry using monoclonal antibodies against CD4 CD25 FoxP3 CD45RO CD95 CCR4 and CLA The levels of TGF-beta and IL-10 were also determined in serum samples from patients with DM by enzyme-linked immunosorbent assays Controls included patients with cutaneous lupus erythematosus psoriasis and atopic dermatitis (AD) as well as healthy donors The frequency of FoxP3(+) cells was significantly reduced in skin lesions from patients with DM (p < 0 001) compared to psoriasis and AD Moreover the number of cells positive for TGF-beta was lower in DM than in psoriasis and AD while IL-10(+) cells were significantly reduced only compared to psoriasis The number of CD4(+)CD25(+) FoxP3(+) Treg in the peripheral blood of patients with DM was significantly reduced compared to healthy controls (p < 0 05) whereas other cell populations showed no significant differences Finally TGF-beta and IL-10 serum levels were significantly lower in patients with DM compared to healthy controls (p < 0 05) These data suggest that the depletion of Treg and their main effector cytokines in the skin and the serum of patients with DM may be an important factor in the pathogenesis of the disease (c) 2010 Elsevier Ltd All rights reserved