Vascular aspects of graft versus host disease

Graft-versus-host disease (GvHD) was regarded as an epithelial cell disease. Three organs - the skin and mucous membranes, digestive tract and liver - are mainly involved in GvHD. Recently it has been experimentally shown and confirmed in human GvHD that endothelial cells are early target of allogeneic immune response and are destroyed by apoptosis. The ultrastructural studies show that the microvessel lesions are focal and that endothelial cell lesions can accompany microvessel lesions in the severe forms of pericapillary haemorrhage. The chimerism assessment allows evaluation of endothelial repair in human acute GvHD. In the chronic phase, microvessel loss with accelerated arteriosclerosis is observed. Endothelial lesions can also be demonstrated in the development of transplant-associated microangiopathy and veino-occlusive liver disease arising after transplantation. The severity of veno-occlusive liver in clinical GvHD has led to the study of new therapeutics targeting endothelial lesions in these diseases.