Vol.23 No.3

Original Article

Anti-CADM-140/MDA5 autoantibody titer correlates with disease activity and predicts disease outcome in patients with dermatomyositis and rapidly progressive interstitial lung disease

Authors

Shinji Sato1 , Masataka Kuwana2 , Takashi Fujita3 , Yasuo Suzuki1

  • Division of Rheumatology, Department of Internal Medicine, Tokai University School of Medicine, 142 Shimokasuya, Isehara 160-8582, Japan
  • Division of Rheumatology, Department of Internal Medicine, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
  • Laboratory of Molecular Genetics, Institute for Virus Research Kyoto University, 53 Shogoin-kawaharacho, Sakyo-ku, Kyoto 606-8507, Japan
Received:

7 March 2012

Accepted:

1 May 2012

Published online:

29 May 2012

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Abstract

Objectives We examined the relationship between disease activity and anti-CADM-140/MDA5 titer measured by enzyme-linked immunosorbent assay (ELISA).
Methods Sera from 63 patients with dermatomyositis (DM) [46 classic DM, 17 clinically amyopathic DM (CADM)] were screened for autoantibody using immunoprecipitation assay. Anti-CADM-140/MDA5-positive sera were examined for their titer by anti-CADM-140/MDA5 ELISA. Potential associations between anti-CADM-140/MDA5 titer and clinical course or outcome were analyzed.
Results Sera from 14 patients with DM (2 classic DM, 12 CADM) had anti-CADM-140/MDA5. Of ten patients with DM and rapidly progressive interstitial lung disease (RPILD), the mean titer of anti-CADM-140/MDA5 before treatment was significantly lower in patients who responded to therapy and survived (responder group, n = 4) than in those who did not respond and died (nonresponder group, n = 6) (110.3 vs. 356.9, P = 0.019). In the responder group, the mean titer of anti-CADM-140/MDA5 significantly decreased down to below the cutoff level after treatment (n = 3, 113.4 vs. 1.6, P = 0.033), whereas that of the nonresponder group did not decrease sufficiently and sustained high level (n = 4, 372.5 vs. 198.4, P = 0.31).
Conclusions These results emphasize the clinical importance of anti-CADM-140/MDA5 antibody levels to predict outcomes of RP-ILD as well as to monitor disease activity in patients with DM and RP-ILD.

Key words

Anti-CADM-140 autoantibody, Anti-MDA5 autoantibody, Clinically amyopathic dermatomyositis (CADM), Dermatomyositis (DM), Rapidly progressive interstitial lung disease (RP-ILD)