Anti-MDA5 and anti-TIF1-gamma antibodies have clinical significance for patients with dermatomyositis

作者：Hoshino Kei; Muro Yoshinao^*; Sugiura Kazumitsu; Tomita Yasushi; Nakashima Ran; Mimori Tsuneyo

来源：Rheumatology, 2010, 49(9): 1726-1733.

DOI：10.1093/rheumatology/keq153

• Amyopathic dermatomyositis
• Anti-MDA5 antibody
• Anti-TIF1-gamma antibody
• Cancer
• Dermatomyositis
• Interstitial lung disease
• Myositis-specific autoantibody

Methods. We screened 135 Japanese patients with various CTDs, including 82 with DM. DM patients were classified as clinically amyopathic DM (CADM), cancer-associated DM or classical DM without cancer. Anti-MDA5 and anti-TIF1-gamma antibodies were detected by their ability to immunoprecipitate biotinylated recombinant proteins.
Results. Sera from 21 (26%) of 82 DM patients immunoprecipitated MDA5, and every anti-MDA5-positive patient had DM (except one patient with SSc). Sera from 20 (65%) of 31 CADM patients reacted with MDA5. Notably, anti-MDA5-positive DM patients had significantly more interstitial lung disease than anti-MDA5-negative DM patients (95 vs 32%, P < 0.001). Sera from 12 (15%) of 82 DM patients immunoprecipitated TIF1-gamma, and anti-TIF1-gamma antibodies were only detected in DM patients. Strikingly, 7 (58%) of 12 patients with cancer-associated DM had sera that reacted with TIF1-gamma. Anti-TIF1-gamma-positive DM patients had significantly more internal malignancies than anti-TIF1-gamma-negative DM patients (58 vs 9%, P < 0.001).
Conclusions. Anti-MDA5 and anti-TIF1-gamma antibodies were confirmed to be serological DM subset markers. Anti-MDA5 and anti-TIF1-gamma antibodies were detected based on their ability to immunoprecipitate biotinylated recombinant MDA5 and TIF1-gamma, and were closely associated with life-threatening complications in DM.

• 出版日期2010-9