The clinical significance of antibodies to human vascular endothelial cells after cardiac transplantation.

Background: Vascular endothelial cells are primary targets for injury during both cellular and humoral allograft rejection (AR). In cardiac transplantation, the role of humoral immunity in mediating AR has not been extensively characterized.
Methods: Antibodies against human vascular endothelial cells (AECA) were measured using a cellular ELISA developed from human umbilical vein endothelial cells in 80 consecutive patients after cardiac transplantation. The aim was to determine the incidence of AECA formation after transplantation and their association with different types of AR, graft survival, and development of cardiac allograft vasculopathy (CAV). At least eight serum samples obtained from each patient were examined for AECA and an endomyocardial biopsy was performed at regular intervals during the first year after transplantation.
Results: Of the 80 patients examined, 31 were AECA (+) and 49 patients were AECA (-). There were no significant differences between the AECA (+) and (-) groups when examined for age, sex, and pretransplantation ischemia time. A significant correlation was found between the presence of AECA and humoral AR (P<0.015). AECA positivity did not correlate with the presence of cellular AR or the number of rejection episodes. In addition, allograft survival at 2 years after transplantation was significantly better in the AECA (-) group compared with that in the AECA (+) group (89.8% vs. 71.0%, P<0.0004). The persistence of AECA positivity during the first year after transplantation was also associated with a significantly greater incidence of CAV when compared with the patients who were AECA (-) (25.8% vs. 14.3%, P<0.004).
Conclusions: AECA may be important in the mediation of humoral AR, may decrease allograft survival, and may identify a high-risk group for CAV.