We showed previously that the heart failure biomarker soluble ST2 (sST2) (which is also called interleukin-1 receptor-like 1/IL1RL1) was significantly elevated in the sera of patients with clinically suspected and biopsy confirmed myocarditis, but only in men with myocarditis that were under 50 years of age (4). Here, IL1RL1 is linked to myocarditis.