Background/Purpose: Human leukocyte antigen-G is a non-classical MHC–I molecule that may be involved in the pathogenesis of autoimmune diseases, but the significance of HLA-G in polymyositis/dermatomyositis (PM/DM) remains to be determined. The aim of this study was to determine HLA-G expression in patients with PM/DM.

Methods: Consecutive cryosections of muscle biopsies obtained from 30 PM/DM patients(22 DM, 8 PM)and 8 healthy controls were detected by immunohistochemical analysis. Serum soluble HLA-G (sHLA-G) levels of 96 patients (26 PM, 70 DM) and 35 matched healthy controls were measured by ELISA. The relationship between sHLA-G levels and clinical or laboratory variables in PM/DM patients was analyzed.

Results:  HLA-G had a higher expression in 18 of 30 cases of PM/DM (60%) than that in 0 of 8 healthy controls (P =0.000). Serum level of sHLA-G in PM/DM patients were significantly higher than healthy controls [(43.96±70.20)U/ml vs (4.22±5.13)U/ml, P=0.000]. Importantly, serum sHLA-G levels in non-treated PM/DM patients(75.75±99.07 U/ml)were significantly higher than that in treated patients(33.94±51.97)U/ml, P=0.021]. Spearman rank correlation analysis showed serum sHLA-G levels were negatively correlated with CD3+Tcells(r=-0.233, P=0.047)and CD4+Tcells (r=-0.287, P=0.015) in peripheral blood in patients with PM/DM.

Conclusion: HLA-G was found to be highly expressed in muscle tissues and sera from patients with PM/DM. Serum sHLA-G is increased in PM/DM patients and is associated with lower level of CD3+T cells and CD4+T cells. These data support the notion that HLA-G overexpression has a role in the progression of PM/DM through T cells.

ACR Meeting Abstracts - https://acrabstracts.org/abstract/expression-of-human-leukocyte-antigen-g-in-polymyositis-or-dermatomyositis/