Objectives: To investigate the clinical characteristics of patients positive for anti-melanoma differentiation-associated gene 5 (MDA5) antibodies, and to analyse the potential pathogenesis of anti-MDA5 antibodies.
Methods: The clinical manifestations, serological tests, imaging features, treatments, and prognoses of 32 anti-MDA5 antibody-positive patients diagnosed in the Rheumatology and Immunology Department of the Second Affiliated Hospital of Chongqing Medical University from September 2015 to August 2018 were analysed.
Results: Of the 32 anti-MDA5 antibody-positive patients, eleven patients were clinically diagnosed with interstitial pneumonia with autoimmune features (IPAF), ten patients were diagnosed with clinically amyopathic dermatomyositis (CADM), six patients were diagnosed with dermatomyositis (DM) and five patients were diagnosed with anti-synthetase syndrome (ASS). Thirty patients had various degrees of pulmonary interstitial changes. The incidence of mortality, subcutaneous emphysema, hoarseness and dysphagia in patients who were positive for both anti-MDA5 and anti-Ro52 antibodies was significantly higher than in patients positive for only anti-MDA5 antibodies. The anti-MDA5 antibody-positive IPAF patients had a very poor prognosis, and mortality in these patients was as high as 54.55%.
Conclusions: Anti-MDA5 antibodies are closely related to interstitial lung disease (ILD). The presence of both anti-MDA5 and anti-Ro52 antibodies indicates poor prognosis.