Distribution of anti-melanoma differentiation associated gene 5 (MDA5) IgG subclasses in MDA5+ dermatomyositis.

Abstract

OBJECTIVES:

The anti-melanoma differentiation-associated gene 5 (MDA5) antibody is the main predictor of interstitial lung disease (ILD) in DM and clinically amyopathic DM (CADM). Nevertheless, a subset of MDA5+ patients have a favourable prognosis. We aimed to determine the possibility of using anti-MDA5 antibody isotypes and IgG subclasses for evaluating ILD risk.

METHODS:

The isotypes (IgG, IgA and IgM) of anti-MDA5 were detected in serum samples of 36 anti-MDA5+ patients with DM/CADM using ELISA. IgG subclasses of anti-MDA5 antibodies were further investigated. Laboratory findings and cumulative survival were analysed based on the isotypes of anti-MDA5 and subclasses of anti-MDA5 IgG.

RESULTS:

Among the MDA5+ patients with DM/CADM, the positive rates of anti-MDA5 IgG, IgA and IgM were 100, 97 and 6%, respectively. The positive rates of anti-MDA5 IgG1, IgG2, IgG3 and IgG4 were 72, 25, 0 and 28%, respectively. The incidence of acute interstitial pneumonia, mortality rate and serum ferritin were significantly higher in anti-MDA5 IgG1+ patients than in anti-MDA5 IgG1- patients with DM/CADM (P = 0.0027, 0.015, 0.0011, respectively). The sensitivity and specificity of anti-MDA5 IgG1 for predicting mortality were 100 and 41.7%, respectively. A combination of anti-MDA5 IgG1 and IgG4 for predicting mortality yielded better specificity (87.5%).

CONCLUSION:

IgA and IgG are the primary anti-MDA5 antibody isotypes. Anti-MDA5 IgG1 is the primary component of MDA5 IgG subclasses and anti-MDA5 IgG1 and IgG4 might serve as useful biomarkers for predicting mortality in DM-ILD.

• Authors: Mengya Chen, Qian Zhao, Licheng Diao, Ke Xue, Yeping Ruan, Feng Xue, Jian Li, Ruofei Shi, Meng Pan, Jie Zheng, Hua Cao
• Journal: Rheumatology (Oxford, England) (Rheumatology (Oxford)) Vol. 61 Issue 1 Pg. 430-439 (12 24 2021) ISSN: 1462-0332 [Electronic] England
• PMID: 33742662 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: © The Author(s) 2021. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved. For permissions, please email: [email protected].

Chemical References

• Biomarkers
• Immunoglobulin Isotypes
• IFIH1 protein, human
• Interferon-Induced Helicase, IFIH1

Topics

• Adult
• Aged
• Biomarkers (blood)
• China (epidemiology)
• Dermatomyositis (diagnosis, immunology, mortality)
• Female
• Humans
• Immunoglobulin Isotypes (blood)
• Interferon-Induced Helicase, IFIH1 (immunology)
• Lung Diseases, Interstitial (etiology)
• Male
• Middle Aged
• Prognosis
• Retrospective Studies
• Young Adult