KRT18 and hemorrhagic fever with renal syndrome: Endothelial cell destruction, possibly leading to increased vascular permeability, might occur in HFRS patients, as elevated levels of caspase-cleaved cytokeratin-18, a marker of endothelial/epithelial apoptotic cell death, and of cell-free DNA and lactate dehydrogenase have been documented in HFRS patients, indicating increased cell death [52], [53].