Autoantibodies to transcription intermediary factor 1 in dermatomyositis shed insight into the cancer–myositis connection

Phenotype-specific autoantibodies are clinically important toolsAcross the breadth of autoimmune rheumatic diseases, there is a striking association of specific autoantibodies with distinct clinical phenotypes, making them excellent tools for subsetting patients, predicting disease course and outcomes.Within the myositis spectrum, there are numerous examples of this.Over two decades ago, it was noted that autoantibodies against the aminoacyl tRNA synthetases (the most frequently targeted of which is Jo-1) are found in myositis patients with a constellation of symptoms known as the "synthetase syndrome"[1-2].These include mechanic's hands, interstitial lung disease, inflammatory arthritis, Raynaud's phenomenon and fever.A more recently described specificity is that of melanoma differentiation-induced gene-5 (MDA-5) -these antibodies are found in dermatomyositis (DM) patients with mild/absent muscle disease, and are frequently associated with rapidly progressive interstitial lung disease [3].New data continue to further define the clinical phenotype associated with anti-MDA-5 antibodies: in a study of DM patients seen at a Dermatology outpatient clinic, Fiorentino et al demonstrated that this specificity is associated with cutaneous ulcerations and distinctive palmar papules, and confirmed the association with rapidly progressing lung disease [4].These two examples confirm that autoantibodies in DM patients are of clinical utility.