Detection of anti-vascular endothelial cell antibodies with microcytotoxicity testing

Antivascular endothelial cell antibodies (anti-VEC) were detected in 20 out of 20 serum samples from post renal transplant nephrectomy patients using a microcytotoxicity (MET) test, but in only 1 of 100 healthy blood donors. Cytotoxicity to VEC could occur in the absence of lymphocytotoxic antibodies. In this paper factors influencing the specificity and sensitivity of microcytotoxicity on vascular endothelial cell (VEC) were studied, including improvements in the preparation of VEC from an umbilical cord vein to get 95% and more of purity and viability; adequate dilution of rabbit sera to reduce its nonspecific VEC cytotoxic effect; and results read by exactly adjusted phase contrast microscopy to reduce the percentage of false negative. The original titers of allotypic and monoclonal antibodies against VEC have been shown to be reproducible in repeated testing during the past two years. The recognition of the weak cytotoxic effects of anti-HLA on VEC makes possible direct application of microcytotoxicity on VEC, to detect anti-VEC and to study VEC antigen classification (through a comparison of the cytotoxic effects of tested sera on VEC and concordant lymphocytes).