1. Rates of acute rejection including subclinical rejection - acute T cell mediated (cellular) rejection, antibody mediated acute rejection, and chronic antibody-associated injury (i.e.: Transplant Glomerulopathy, Chronic allograft arteriopathy) between the groups.
2. Evaluation of endothelial cell activation and injury on biopsies by checking markers for endothelial cell activation and injury (intercellular adhesion molecule-1, ICAM-1/CD54; vascular cell adhesion molecule-1, VCAM-1/CD106; and E-selectin, ELAM-1/CD62E) in two-color stains of tissue with classical endothelial markers (CD34 and Factor VIII).
3. Measurement of serum/plasma levels of TNF-alpha and VEGF and decreased levels of protein C and protein S in the circulation, as an assessment of graft vascular perturbation.
4. Circulating Endothelial Cells (CECs) will be measured by flow cytometry with markers for endothelial cell activation.
