Idiopathic inflammatory myopathy patients with different autoantibody exhibit unique peripheral blood T cell subsets

Abstract

Abstract Idiopathic inflammatory myopathy (IIM), a heterogeneous group of systemic autoimmune diseases, is characterized clinically by weakness of skeletal muscle. Patients with IIM often show a myositis-specific autoantibody (MSA) such as anti-melanoma differentiation-associated gene-5 (MDA5 group) or anti-aminoacyl-tRNA synthetase (ARS group, including Jo-1, EJ, PL-12, PL-7, OJ, and KS), indicating that the adaptive immune system may alter in IIM patients. T cells (CD3+) play important roles in regulation of the adaptive immune system and usually subdivide into naïve cells (TN) and memory T cells (TM). Based on the surface expression of different cell markers, TM cells can be divided into central memory T (TCM, CD45RA−CD62L+) and effector memory T (TEM, CD45RA−CD62L−) cells. After antigenic stimulation, a subset of TEM cells re-expresses CD45RA, called TTEMRA. Here we examined peripheral blood T cell subsets in MDA5 group (n=22), ARS group (n=34) and healthy control individuals (HC group, n=30) using flow cytometry analysis. We found that TTEMRA population was increased in MDA5 group. TN population was reduced and TTEMRA population was enhanced in ARS group. Th17 and Th1 cells were more abundant in MDA5 and in ARS group, respectively. Treg cells was increased in both of MDA5 and ARS group. In addition, in MDA5 group, death patients (n=5) had fewer Treg cells compared with alive patients (n=17), suggesting reduced Treg cells may be associated with mortality. Therefore, peripheral blood T cell subsets may be correlated with specific clinical manifestations for IIM patients with distinct MSA.