Three cases report of juvenile dermatomyositis with positive anti-melanoma differentiation associated gene 5 (MDA5) antibody and severe interstitial lung disease and literature review / 中华儿科杂志

ABSTRACT

Objective@#To report the clinical features of anti-MDA5 antibody positive juvenile dermatomyositis (JDM) complicated with severe interstitial lung disease (ILD).@*Methods@#The clinical data of three patients, who was admitted to the Department of Rheumatology and Immunology, Children's Hospital of the Capital Institute of Pediatrics from September 2016 to July 2017, with anti-melanoma differentiation associated gene 5 (MDA5) antibody positive JDM complicated with ILD were retrospectively extracted and analyzed. Meanwhile, PubMed database, CNKI, Wanfang database and China Biology Medicine disc (from their establishment to February 2019) with the key words "juvenile dermatomyositis" "interstitial lung disease" , and "anti-MAD5 antibody" both in English and Chinese were searched.@*Results@#There were 2 females and 1 male (P1-P3), aged from 10 years 3 months to13 years 4 months, the time from onset to diagnosis were 2 months, 4 months and 10 months. All presented with rash. One of them had decreased muscle strength, and two had decreased activity tolerance. Creatine kinase was 588, 915 and 74 U/L, and serum ferritin were 1 792, >2 000 and 195.4 μg/L. All three patients had positive anti-MDA5 antibodies. At the time of diagnosis, all of them had ILD, pneumothorax and mediastinal emphysema, but had no respiratory symptoms. All three patients received oral methylprednisolone and cyclophosphamide pulse therapy, while human immunoglobulin was given only to P1 and P2. P1 developed rapid progressive pulmonary interstitial disease (RPILD) and died of respiratory failure after 2 months. While P2 and P3 were followed up for 1 to 2 years, who had complete remission, as anti-MDA5 antibody turned to negative and ILD improved significantly. Ten related reports in literature were retrieved, without reported Chinese cases, and most cases initiated with rash and very likely complicated with arthritis. Some of them were more likely to have ILD rather than muscle weakness. It also showed that Japanese JDM children had higher rate of positive anti-MDA5 antibody than patients from the U.S. and U.K., and are more susceptible to ILD and RPILD. The mortality rate of patients with RPILD is extremely high.@*Conclusions@#The cases of JDM with positive anti-MDA5 antibody mainly presented with rash and mild muscle weakness, and could be complicated with ILD, pneumothorax and mediastinal emphysema without respiratory symptoms at early stage. Anti-MDA5 antibody titer is related to disease activity and can turn to negative after treatment.