Elevated ST 2 levels are associated with antibody‐mediated rejection in heart transplant recipients

Soluble ST 2 ( sST 2) is a novel biomarker of inflammation and fibrosis. Elevated sST 2 levels (≥35 ng/mL) are associated with worse outcomes in patients with heart failure ( HF ). There are sparse data regarding the significance of sST 2 levels after heart transplantation ( HT x). The study aims were to evaluate trends in soluble ST 2 levels after the resolution of HF status with HT x and association between post‐ HT x sST 2 levels and outcomes. Plasma sST 2 levels were measured at baseline (median [ IQR ] of 118 days pre‐ HT x) and 12 months post‐ HT x in 62 subjects who were stratified into two groups by post‐ HT x sST 2 levels < or ≥35 ng/mL: “Group 1” or “Group 2,” respectively. Plasma sST 2 levels were elevated in 58% of patients pre‐ HT x and in 50% of patients post‐ HT x. There was no association between elevated sST 2 levels before and after HT x, and no significant differences in baseline characteristics between Group 1 and Group 2 patients. Group 2 as compared to Group 1 HT x recipients had significantly higher incidence of antibody‐mediated rejection ( AMR ) for the entire post‐transplant follow‐up period (32% vs 4%, P  = 0.006). There was no association between post‐ HT x sST 2 level status and other post‐ HT x outcomes including survival. In conclusion, elevated plasma sST 2 levels after HT x are associated with increased risk for AMR.