Arthritis & Rheumatism, Volume 63,
November 2011 Abstract Supplement

Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Chicago, Illinois November 4-9, 2011.


Anti-CADM-140 Autoantibody Titer Correlates with Disease Activity in Patients with Dermatomyositis and Rapidly Progressive Interstitial Lung Disease.

Sato1,  Shinji, Kuwana2,  Masataka, Fujita3,  Takashi, Suzuki1,  Yasuo

Tokai University School of Medicine, Isehara, Japan
Keio University School of Medicine, Tokyo, Japan
Institute for Virus Research and Graduate School of Biostudies, Kyoto University, Kyoto, Japan

Background/Purpose:

Anti-CADM-140 autoantibody is specifically detected in patients with dermatomyositis (DM), especially those who have little or no muscle manifestation (clinically amyopathic dermatomyositis: CADM). Its presence is known to have a strong association with rapidly progressive interstitial lung disease (RP-ILD). Despite its diagnostic utility, the relationship between anti-CADM-140 antibody titer and disease activity is still unknown. Here, we have examined this issue using an enzyme-linked immunosorbent assay (ELISA) to measure anti-CADM-140 titers.

Methods:

Serum samples from 62 patients diagnosed as having adult DM (46 with classical DM and 16 with CADM) at Keio University Hospital or Tokai University Hospital between 2000–2010 were screened for autoantibody using RNA and protein immunoprecipitation assays. Sera containing anti-CADM-140 antibody were then titered using a previously-established ELISA. Associations between anti-CADM-140 titer and clinical course and outcome were analyzed.

Results:

Sera from thirteen of 62 patients with DM were found to contain anti-CADM-140 antibody. Two had classical DM and 11 had CADM. Ten patients had ILD, of whom 9 developed RP-ILD. In the latter, the mean titer of anti-CADM-140 antibody before treatment was significantly lower in those who responded to therapy and survived (responder group, n=3) than in those who did not respond and died (non-responder group, n=6) (101.6 units vs. 351.4 units, p= 0.018). In the responder group, the mean titer of anti-CADM-140 antibody decreased to below the cut-off level after treatment, in parallel with improved respiratory symptoms (n= 3, 101.6 units vs. 1.5 units, p= 0.041, cut-off level = 8.0 units). In contrast, the mean anti-CADM-140 titer in the non-responder group did not decrease significantly and was maintained at a high level over the disease course (n=4, 364.2 units vs. 198.4 units, p=0.17). Interestingly, the anti-CADM-140 titer remained below the cut-off level after improvement of RP-ILD in the three surviving patients.

Conclusion:

These results illustrate the clinical utility of anti-CADM-140 antibody to predict the development of RP-ILD as well as to monitor disease activity and to assess the response to treatment in patients with DM and RP-ILD.

To cite this abstract, please use the following information:
Sato, Shinji, Kuwana, Masataka, Fujita, Takashi, Suzuki, Yasuo; Anti-CADM-140 Autoantibody Titer Correlates with Disease Activity in Patients with Dermatomyositis and Rapidly Progressive Interstitial Lung Disease. [abstract]. Arthritis Rheum 2011;63 Suppl 10 :226
DOI:

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