IFIH1 and edema: Anti-MDA5 autoantibodies were significantly associated with the occurrence of both skin ulceration (52% anti-MDA5 positive versus 27% anti-MDA5 negative, P = 0.03) and oral ulceration (71% anti-MDA5 positive versus 45% anti-MDA5 negative, P = 0.01) occurring at any time point during the follow-up period but not with oedema or calcinosis.