Abnormally increased low-density granulocytes in peripheral blood mononuclear cells are associated with interstitial lung disease in dermatomyositis

Abstract

Objective: We previously found that neutrophil extracellular traps (NETs) were associated with interstitial lung disease (ILD) in dermatomyositis (DM) patients. However, it is unclear whether low-density granulocytes (LDGs), endowed with enhanced NET formation capabilities, contribute to the pathogenesis of ILD. This study aims to elucidate the relationship between LDGs and DM-associated ILD.

Methods: We recruited 48 DM patients (28 with ILD) as well as 19 healthy volunteers for this study. The percentage of LDGs in peripheral blood mononuclear cells (PBMCs) was ascertained by flow cytometry. Plasma cfDNA was measured by using the Quant-iT PicoGreen dsDNA Kit and plasma LL-37 was tested by using the LL-37 ELISA kit.

Results: The percentage of LDGs was 7.1 times higher in DM patients than in healthy controls. LDG percentage was 2.7 times higher in DM patients with ILD than in DM patients without ILD. Additionally, LDG percentage positively correlated with MYOACT lung disease activity scores, and NET/neutrophil-related marker levels (LL-37, cfDNA, MPO, and MMP-8) in the DM group were significantly higher than those in the control group.

Conclusion: The abnormal increase of LDGs may exacerbate abnormal NET regulation and further contribute to the pathogenesis of ILD in DM patients by abnormally forming NETs.

Keywords:

• Dermatomyositis
• Interstitial lung disease
• Low-density granulocytes
• Neutrophil extracellular traps

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Corrigendum

Conflict of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article.

Funding

This study was sponsored by the National Natural Science Foundation of China (Grant nos. 81560267 and 81401363) and the APLAR Research Grant 2015.

Supplementary material available online