In a clinical trial on 41 patients with acute myocarditis/DCM and 32 healthy volunteers: the proportion of circulating Th17 cells was significantly elevated in the patient group. In addition, increased Th17 cells were correlated with heart failure, and biopsies with detectable IL-17A+ cells showed greater fibrosis. The gene discussed is IL17A; the disease is familial dilated cardiomyopathy.