Anti‐ACE2 IgM antibodies were assayed by enzyme‐linked immunosorbent assay (ELISA) in two anti‐MDA5‐positive DM cohorts: a predominantly outpatient North American cohort (n = 52) and a Japanese cohort enriched for new‐onset disease (n = 32). The gene discussed is CD40LG; the disease is dermatomyositis.