Alterations of mucosal-associated invariant T cells in dermatomyositis.

OBJECTIVES

The aim of this study is to investigate the frequency and functional changes of mucosal-associated invariant T (MAIT) cells in the peripheral blood of patients with dermatomyositis (DM).

METHODS

Peripheral blood mononuclear cells (PBMCs) from 23 untreated DM patients and 32 healthy controls (HC) were analysed via flow cytometry to assess MAIT cell frequency, activation status, chemokine receptor expression, and cytokine production.

RESULTS

The frequency of circulating MAIT cells was significantly decreased in the DM group compared with the HC group, while the proportion of CD69+ and PD-1+ MAIT cells was significantly increased, especially in patients with melanoma differentiation-associated gene 5-positive dermatomyositis (MDA5-DM). Moreover, the expression of the chemokine receptors CCR2 and CCR5 on MAIT cells was reduced in DM patients. In addition, the proportion of IFN-γ+ MAIT cells was significantly elevated in DM patients.

CONCLUSIONS

The reduced frequency of MAIT cells in DM may be associated with excessive activation. The increased secretion of IFN-γ by MAIT cells may contribute to DM pathogenesis.