Figure 4.

Natural and induced regulatory T cells (T_regs) are present in psoriatic plaques, but while the frequency of the natural type is similar to that in peripheral blood, induced T_regs can be enriched in lesions from some patients. (a) Immunohistochemistry slides showing that CD4⁺ lymphocytes, forkhead box protein 3 (FoxP3⁺) cells and interleukin (IL)-23R⁺ cells are all found in both the dermis and epidermis of psoriatic lesions. (b) A set of representative flow cytometric data from psoriatic patients are shown, demonstrating the numbers of IL-10⁺-induced T regulatory 1(Tr1) phenotype (upper) and CD25^hiFoxP3⁺ cells within the CD4⁺ lymphocyte (lower) populations from peripheral blood mononuclear cells (PBMC) (middle) and paired lesional biopsies (right). (c) Summarizes data from analyses of CD4⁺ cells from lesional biopsies and blood of psoriatic patients (n = 6), demonstrating the percentages of CD4⁺ cells that express T_reg markers (bar indicates median value).