Clinical Features and Cytokine Profile in Myositis Patients with Anti-EJ Autoantibodies Detected by a Novel Immunoprecipitation Assay

Abstract EN

Objective.

This study aimed to clarify the clinical features, the serum level of autoantibodies, and cytokine of myositis patients with anti-EJ antibody, which targets glycyl tRNA-synthetase (GlyRS).

Methods.

Sera of 236 Chinese patients with myositis were screened for anti-EJ by a novel immunoprecipitation assay of flag-tagged GlyRS.

Anti-EJ positive patients are evaluated for the clinical features and cytokine profile.

Results.

The sera from 4 of 236 adult myositis patients were found to carry the anti-EJ using established novel immunoprecipitation assay and immunoblotting.

The prevalence of anti-EJ in our cohorts is about 1.7%.

The decline of anti-EJ level was detected in two patients during disease remission.

Interstitial lung disease and muscle weakness, but not skin involvement, are common clinical features of anti-EJ positive patients.

Moreover, using a cytokine profile analyses, we found that the serum levels of IP-10, IL-6, MCP-1, and VEGF were significantly elevated in patients with anti-EJ and gradually decreased during disease remission of two patients, whereas IL-8 level was obviously reduced in these patients.

Conclusion.

The novel immunoprecipitation assay is suitable to detect and monitor the levels of anti-EJ autoantibody.

The serum levels of anti-EJ, IP-10, IL-6, MCP-1, and VEGF may be related to disease activity in myositis patients with anti-EJ antibodies.