Mucosal-associated invariant T (MAIT) cell activation and correlation of CD69+ MAIT cell frequency with disease activity in patients with psoriasis

Abstract Mucosa-associated invariant T (MAIT) cells are innate lymphocytes that play a specific role in autoimmune diseases. In particular, the frequency and phenotype of MAIT cells in the pathogenesis of psoriasis is not fully understood. Our study examines the frequency and phenotype of MAIT cells sorted from peripheral blood mononuclear cells (PBMCs) obtained from 53 cases of patients and 44 healthy control.Compared with the healthy control group, the frequency of circulating CD3 + MAIT cells, CD3 + CD8 + MAIT cells, CD4 + CD69 + MAIT and CD8 + CD69 + MAIT cells in psoriasis patients was significantly increased (p < 0.05). While the proportion of CD3 + CD4 + MAIT cells was decreased. Correlations between IL-15 and PASI scores and activated MAIT cells revealed a potential role of MAIT cells in the development of psoriasis. IL-15 was positively correlated with both CD4 + CD69 + MAIT and CD8 + CD69 + MAIT cells. Activated CD3 + MAIT cells and activated CD8 + MAIT cells in patients' serum were both positively correlated with patients' PASI scores, while activated CD4 + MAIT cells and PASI scores were negatively correlated .Our results suggest that the abnormal phenotype of MAIT cells in patients with psoriasis parallels the progression of the disease. These abnormalities may lead to skin and systemic immune disorders in patients with psoriasis.