Preformed antibodies in sensitized recipients: effect of immunoglobulin titer, class, and specificity on liver and heart allografts.

P REFORMED antibodies (Abs) in the blood circulation of recipients before transplantation have been identified as the cause of hyperacute rejection (HAR) of the grafts. 1.2 However, liver allografts are relatively resistant to preformed Abs, and because of conflicting results in clinical practice with sensitized recipients, 3 the practical significance of lymphocytotoxic antibodies (LAbs) in an individual patient is difficult to judge. In this study, we sensitized rats with skin or whole blood and examined in vivo and in vitro characterization of the preformed Abs by actual transplants. LAb assay, flow cytometry, and indirect immunofluorescence (IF) study.