ACR Meeting Abstracts

ACR Meeting Abstracts

Abstract Number: 292

Clinical Utility of Anti-CADM-140/Melanoma Differentiation-Associated Gene 5 Autoantibody Titers in Patients with Juvenile Dermatomyositis and Rapidly Progressive Interstitial Lung Disease

Shinji Sato1, Norimoto Kobayashi2, Kazuko Yamazaki3 and Yasuo Suzuki4, 1Rheumatology, Tokai University School of Medicine, Isehara, Japan, 2Department of Pediatrics, Shinshu University School of Medicine, Matsumoto, Japan, 3Department of Pediatrics, Yokohama City University School of Medicine, Yokohama, Japan, 4Division of Rheumatology, Department of Internal Medicine, Tokai University School of Medicine, Isehara, Japan

Meeting: ACR/ARHP Annual Meeting 2012

Keywords: ,

Session Information

Title: Pediatric Rheumatology - Clinical and Therapeutic Aspects: Pediatric Systemic Lupus Erythematosus, Pediatric Vasculitis and Pediatric Myositis

Session Type: Abstract Submissions (ACR)

Background/Purpose: The presence of anti-CADM-140/ (Melanoma Differentiation-Associated Gene 5: MDA5) autoantibody is specific for adult dermatomyositis (DM), especially in patients with little or no muscle manifestations (clinically amyopathic dermatomyositis: CADM). Its presence is known to have a strong association with rapidly progressive interstitial lung disease (RP-ILD). Recently, it was reported that anti-CADM-140/MDA5 antibody titers measured by an enzyme-linked immunosorbent assay (ELISA) were useful for predicting outcomes of RP-ILD as well as for monitoring disease activity in patients with adult DM and RP-ILD. However, despite its diagnostic utility in adult DM, its clinical significance in juvenile DM (JDM) is still unclear. Here, we have examined this issue using anti-CADM-140/MDA5 ELISA.

Methods: Serum samples from 35 patients diagnosed with JDM (26 with classical JDM and 9 with juvenile CADM) were screened for autoantibody using a previously established anti-CADM-140/MDA5 ELISA. Associations between anti-CADM-140/MDA5 titer and clinical course and outcome were analyzed.

Results: Sera from 11 of 35 patients (31%) with JDM were found to contain anti-CADM-140/MDA5 antibody (6 with classical JDM and 5 with juvenile CADM). All 11 patients who possessed anti-CADM-140/MDA5 antibody had ILD, of whom 6 developed RP-ILD. JDM patients with anti-CADM-140/MDA5 antibody were significantly more likely to have RP-ILD compared with those without this antibody (P=0.0017). In anti-CADM-140/MDA5-positive patients, the mean antibody titer before treatment was significantly higher in those with RP-ILD than in those without (166.7 units vs. 57.4 units, P= 0.048). Four of 6 patients with RP-ILD died despite intensive therapy. In a patient who responded to therapy and survived, the titer of anti-CADM-140/MDA5 antibody decreased to the cut-off level, in parallel with improved respiratory symptoms. In contrast, the mean anti-CADM-140/MDA5 titer in patients who failed to respond to therapy and died did not decrease significantly, being maintained at a high level over the disease course as also observed in patients with adult DM (197.2 units vs. 76.2 units, P=0.17, n=3).

Conclusion: These results illustrate the clinical utility of establishing anti-CADM-140/MDA5 antibody titers in patients with JDM and RP-ILD as well as in patients with adult DM and RP-ILD.

Disclosure:

S. Sato,

Holding a patent on anti-CADM-140/MDA5 antibody-measuring kit,

7;

N. Kobayashi,
None;

K. Yamazaki,
None;

Y. Suzuki,
None.

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