Serum levels of IL-33 and soluble suppression of tumorigenicity-2 (sST2), which is the soluble form of IL-1 receptor-like 1 (IL-33), were significantly higher in HF regardless of the presence HF phenotypes associated with HF symptom severity, LV hypertrophy, and the risk of CV death and hospitalization than in healthy volunteers [118, 119]. The gene discussed is IL33; the disease is hydrops fetalis.