European Grading System for Acute Liver Allograft Rejection
Grade	Criteria
1 (mild)	Portal inflammatory changes are generally mild and patchily distributed. Bile duct damage and venous endothelial inflammation are both mild.
2 (moderate)	Portal inflammatory changes are more severe and widespread. Bile duct damage and venous endothelial inflammation both conspicuous.
3 (severe)	All three classical features of acute rejection are present to a marked degree. They may be accompanied by additional periportal, or vascular changes as outlined below.
The severity of 1) portal inflammation, 2) bile duct damage, and 3) venous endothelial inflammation are graded on a scale of 0 = none to 3 = severe and are then collated to provide a final rejection grade. In some cases additional features, which are seen inconsistently in acute rejection (eg. portal inflammatory spillover, sinusoidal endotheliitis, parenchymal inflammation ± necrosis, arteritis), may be used to upgrade the overall severity of acute rejection.
Reference Hubscher S. Diagnosis and grading of liver allograft rejection: a European perspective. Transplant Proceed 1996;28:504-507.