Neutrophil Extracellular Traps Generation Relates with Early Stage and Vascular Complications in Systemic Sclerosis.

Kevin Didier,Amelie Servettaz,Celine Muller,Christine Terryn,Delphine Giusti,Frank D Antonicelli,Richard Le Naour,Bach Nga Pham,Sebastien Le Jan

doi:10.3390/jcm9072136

Abstract

Systemic sclerosis (SSc) is a systemic disease characterized by a great clinical and immunological heterogeneity whose pathophysiology is still being unraveled. Recently, innate immunity has been proposed to participate to the pathogenesis of SSc. In this study, we investigated the release of neutrophil extracellular traps (NETs) according to patient phenotype. Polymorphonuclear neutrophils (PMN) from 34 SSc patients and 26 healthy controls were stimulated by serum from SSc or healthy subject. NETs were visualized using epifluorescence microscope after DNA, myeloperoxidase, and Histone H3 tagging. Area of NETs were quantified using an original macro running in ImageJ® software. PMN from SSc patients were significantly more prone to releasing NETs than control PMN after autologous stimulation. PMN from patients with severe vascular complications (pulmonary arterial hypertension, digital ulcers) produced more NETs than PMN from other SSc patients and their aberrant NET production appeared to be sustained over time. In patients with pulmonary interstitial disease or extensive cutaneous fibrosis, NET production was high at an early stage of the disease before progressively decreasing. Both serum factors and PMN activation status were involved in the enhanced production of NETs in SSc. Consequently, neutrophils and especially NETosis represent new physiopathological and therapeutic fields in SSc.

Highlights

Systemic sclerosis (SSc) is a rare connective tissue disease characterized by skin and organ fibrosis, vasculopathy, and autoimmunity
We further investigated NETosis according to the cutaneous phenotypes diffuse SSc (dSSc) and limited SSc (lSSc) and did not observe any significant difference between these disease subtypes in autologous conditions of stimulation (p = 0.2156, Figure 4B)
SSc is an autoimmune systemic disease characterized by dysfunctions of endothelial cells, fibroblasts, and immune cells, leading to heterogeneous organ damage that jeopardizes patient survival

Summary

Introduction

Systemic sclerosis (SSc) is a rare connective tissue disease characterized by skin and organ fibrosis, vasculopathy, and autoimmunity. During PMN activation, depending on oxidative stress, cells release DNA filaments covered by histones, enzymes, and other antimicrobial proteins These filaments, called neutrophil extracellular traps (NETs) are involved in defense against bacteria and their formation leads in most of cases to the death of PMN [12]. This release of NETs, called NETosis, has been highlighted in autoimmune diseases such as systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), bullous pemphigoid, and antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis [13,14,15,16]. We wondered whether NETosis occurring during SSc could be differently modulated according to the phenotype of SSc, reflecting the heterogeneous clinical expression of this disease

Study Population

Data Collection

Antinuclear Antibody Detection

Statistical Analysis

Subject Characteristics

Discussion