Session Information
Date: Monday, October 22, 2018
Session Title: Muscle Biology, Myositis and Myopathies Poster II: Basic and Translational Science
Session Type: ACR Poster Session B
Session Time: 9:00AM-11:00AM
Background/Purpose: Low density granulocytes (LDGs) are a subset of neutrophils that spontaneously produce neutrophil extracellular traps (NETs) and type I IFN. The latter correlates with disease activity and IFN regulated genes had been found in atrophic muscle fibers of patients with idiopathic inflammatory myopathies (IIM). However, the role of this subset of neutrophils has not been fully addressed in IIM. The aim of this study was to assess the relationship between LDGs, disease activity and damage in patients with IIM.
Methods: We recruited 65 adult patients with dermatomyositis, polimyositis, and anti-synthetase syndrome according to the respective classification criteria. The percentage and absolute number of LDGs were assessed by flow cytometry as those CD10+, CD15+and CD14–cells in the mononuclear fraction. Disease activity and damage were evaluated by two Rheumatologists. Complete clinical response was defined as the absence of muscular and extra muscular disease activity with immunossupressive therapy.
Results: The most frequent diagnosis was adult onset dermatomyositis (67.6%). Patients with calcinosis and dysphagia had higher amount of LDGs (Table 1). There was a trend towards higher amount of LDGs in patients with anti MDA5 antibodies. LDGs correlated with disease activity scales (MMT8, muscle enzymes, the patient’s and physician’s visual analogue scale (VAS) of disease activity) as well as with the extension and severity of damage (Table 2). Only 23.9% of patients had clinical complete response and those subjects had significantly lower levels of LDGs (0.17 (0.08-0.49) vs 0.46 (0.23-1.35), P=0.030).
Conclusion: LDGs are expanded in subjects with active IIM, especially in those with signs of vasculopathy (calcinosis) and dysphagia. LDGs correlate with disease activity and damage scales. Also, patients with anti MDA5 antibodies whom are characterized by an intense IFN signature have higher amount of LDGs. Our findings support the role of LDGs in the induction of disease activity and damage in patients with IIM and suggest that they may serve as a biomarker to identify patients with active disease in contrast with those with complete clinical response.
Table 1.
|
Feature |
Present |
Absent |
P |
|
Calcinosis |
1.17 (0.35-2.52) |
0.32 (0.15-0.91) |
0.035 |
|
Dysphagia |
1.66 (0.28-2.7) |
0.32 (0.15-0.83) |
0.028 |
|
Anti-MDA5 |
2.37 (2.17-) |
0.27 (0.1-0.84) |
0.076 |
Table 2.
|
Feature |
Rho |
P |
Feature |
Rho |
P |
|
MMT8 |
-0.4 |
0.001 |
Neutrophil/ lymphocyte ratio |
0.31 |
0.013 |
|
Physician VAS |
0.310 |
0.012 |
Patient VAS |
0.308 |
0.013 |
|
ALT |
0.319 |
0.011 |
AST |
0.298 |
0.018 |
|
Muscle damage VAS |
0.339 |
0.001 |
Cutaneous damage VAS |
0.31 |
0.011 |
|
Damage extension |
0.324 |
0.009 |
Damage severity |
0.297 |
0.017 |
To cite this abstract in AMA style:
Torres-Ruíz J, Leal-Alanis A, Vazquez-Rodriguez R, Alvarado-Lara MR, Carazo-Vargas ER, Maravillas-Montero JL, Alcocer-Varela J, Gómez-Martín D. Low Density Granulocytes As Biomarkers of Disease Activity and Damage in Patients with Idiopathic Inflammatory Myopathies [abstract]. Arthritis Rheumatol. 2018; 70 (suppl 10). https://acrabstracts.org/abstract/low-density-granulocytes-as-biomarkers-of-disease-activity-and-damage-in-patients-with-idiopathic-inflammatory-myopathies/. Accessed January 20, 2020.« Back to 2018 ACR/ARHP Annual Meeting
ACR Meeting Abstracts - https://acrabstracts.org/abstract/low-density-granulocytes-as-biomarkers-of-disease-activity-and-damage-in-patients-with-idiopathic-inflammatory-myopathies/