ABSTRACT
Background: Psoriasis is a common chronic inflammatory disease caused by excessive activation of CD4+T cells, including Th17, Th1 and Th22. The role of CD8+T cells in psoriasis pathogenesis remains poorly understood. Aim: To identify the phenotype of CD8+T cells in patients with psoriasis and to investigate its role in the formation of lesions. Methods: The phenotype of CD8+T cells in psoriatic lesions was detected by immunofluorescence staining. Flow cytometry was performed to detect their phenotype in peripheral blood. Thereafter, coculture of CD8αα+T cells with autogenous CD4+T cells was performed to investigate the function of CD8αα+T cells in patients with psoriasis. Finally, pro-inflammatory factors produced by CD8αα+T cells were examined by immunofluorescence staining and flow cytometry. Results: Compared to the CD8αß+T cells, CD8αα+T cell infiltration in psoriatic lesions markedly increased. Moreover, epidermal CD8αα+T cells exhibited tissue-resident memory T cells (TRM) phenotypes and dermal CD8αα+T cells exhibited effector memory (TEM) phenotypes in psoriatic lesions. Additionally, we found that CD8αα+T cells from patients with psoriasis did not express the markers of regulatory T cells and could promote the proliferation of CD4+T effector cells and produce interleukin-17 and interferon-γ. Conclusions: Our findings demonstrate that CD8αα+T cells contribute to the pathogenesis of psoriasis by producing pro-inflammatory factors.
ABSTRACT
BACKGROUND: Psoriasis is an immune disorder involving numerous cytokines. Recent studies have shown that interleukin (IL)-21 plays an important role in a variety of inflammatory and autoimmune diseases. It is highly expressed in psoriatic plaques and promotes the proliferation of epidermis in mice. It seems that IL-21 plays an important role in the pathogenesis of psoriasis. However, whether or not it is elevated in the peripheral blood of patients with psoriasis and is associated with disease severity is unclear. Therefore, our study focuses on serum IL-21 levels and their correlation with disease severity. OBJECTIVES: To detect serum IL-21 levels in patients with psoriasis and investigate the correlation between these and the Psoriasis Area and Severity Index (PASI) scores. METHODS: Blood samples were collected from patients with plaque psoriasis and from healthy control subjects. Serum IL-21 levels were measured by enzyme-linked immunosorbent assay in 37 patients with psoriasis and 37 healthy controls. The PASI scores of patients with psoriasis and their correlation with serum IL-21 levels were evaluated. RESULTS: Serum IL-21 levels were higher in patients with psoriasis than in healthy controls (P < 0·01). Serum IL-21 levels were positively correlated with PASI scores in the patients with psoriasis (r = 0·471, P < 0·01). CONCLUSIONS: Serum IL-21 levels in patients with psoriasis are elevated and positively correlate with PASI scores. These results indicate that IL-21 may play an important role in the pathogenesis of psoriasis.
