Arthritis & Rheumatism, Volume 62,
November 2010 Abstract Supplement

Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Atlanta, Georgia November 6-11, 2010.


Anti-CADM-140/MDA5 Antibody Predicts Complication of Interstitial Lung Disease in Japanese Cases of Juvenile Dermatomyositis.

Kobayashi1,  Ichiro, Okura1,  Yuka, Yamazaki1,  Yasuhiro, Takezaki1,  Shunichiro, Yamada1,  Masafumi, Kuwana2,  Masataka, Ariga1,  Tadashi

Department of Pediatrics, Hokkaido University Graduate School of Medicine, Sapporo, Japan
Keio University School of Med, Tokyo, Japan

Background:

Interstitial lung disease (ILD) is a life-threatening complication of both adult dermatomyositis (DM) and juvenile dermatomyositis (JDM). We have indicated that most of ILD develops at an early stage or at the time of relapse of JDM and is rapidly or moderately progressive (Kobayashi I, et al. Rheumatology 2003). Among ILD associated with DM, rapidly progressive interstitial pneumonia preferentially develops in clinically amyopathic DM (CADM) particularly in Asian races (Sontheimer RD. Arch Dermatol. 2010). Recently, anti-CADM-140/MDA5 antibody has been identified as a disease marker for ILD associated with adult CADM. In the present study, we examined the autoantibody in JDM complicated with or without ILD.

Materials and Methods:

Thirteen cases of JDM including 6 cases with ILD were involved in this study. The diagnosis of JDM was made according to the diagnostic criteria by Bohan and Peters. Sera were obtained from the patients at the time of diagnosis of JDM and stored at -20°C until use. Anti-CADM-140/MDA5 antibody was measured by enzyme-linked immunosolbent assay using purified recombinant MDA-5 as an antigen as previously described (Sato S, et al., Arthritis Rheum 2009). The antibody units were calculated from the optical density at 450 nm results (normal range: <8.0 U).

Results:

Although case 1 died of respiratory failure, the other four previously reported cases showed recovery following the commencement of cyclosporine A in combination with methylprednisolone pulse therapy and oral high-dose prednisolone, and are drug-free for at least four years without relapse of either JDM or ILD. In an additional case, ILD developed approximately two months after the diagnosis of JDM which was associated with elevation of a serum KL-6 level (2,376 U/ml). This case is now successfully treated with cyclosporine A in combination with prednisolone following methylprednisolone pulse therapy. All the cases with ILD showed clinically apparent myositis associated with elevated levels of serum muscle derived enzymes during the course. Among the seven cases without ILD, two cases lacked both clinical myopathy and elevation of muscle-derived enzymes.

Five of the six cases with ILD were positive for the anti-CADM-140/MDA5 antibody (9.5–902.3 U). Three cases with rapidly progressive ILD showed extremely high levels of the antibody (357.6–902.3 U). In two cases in which ILD developed more than 1 month after the diagnosis of JDM, the antibody was detected before the development of ILD. All of the 7 cases without ILD were negative for the antibody (1.3–3.5 U).

Conclusion:

Anti-CDMA140/MDA-5 autoantibody is not only a disease marker for ILD associated with JDM but also a predictive marker for the complication regardless of the muscle weakness. Our results suggest that common or similar mechanisms are involved in the development of ILD in both adult CADM and JDM.

To cite this abstract, please use the following information:
Kobayashi, Ichiro, Okura, Yuka, Yamazaki, Yasuhiro, Takezaki, Shunichiro, Yamada, Masafumi, Kuwana, Masataka, et al; Anti-CADM-140/MDA5 Antibody Predicts Complication of Interstitial Lung Disease in Japanese Cases of Juvenile Dermatomyositis. [abstract]. Arthritis Rheum 2010;62 Suppl 10 :1672
DOI: 10.1002/art.29437

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