CD44 and fibrosis: Since heart failure is one of the main causes of rejection following HTx, we should also focus on the relationships between the four hub genes ICAM1, CD44, HLA‐A and HLA‐B and heart failure: Intramyocardial endothelial ICAM1 was found to promote cardiac inflammation and pathological cardiac remodelling by promoting T cell recruitment in the left ventricle, which contributes to cardiac fibrosis and dysfunction and heart failure.38