Effect of immunomodulatory artificial blood exchange (IABX) on guinea pig-to-rat heart xenografts.

The aim of this study was to assess the effectiveness of pregraft immunomodulatory artificial blood exchange (IABX) in a guinea pig-to-rat xeno discordant heart transplantation, using an artificial blood (FC43 emulsion: The Green Cross, Japan) in exchange for a large volume of whole blood to remove humoral immune factors en bloc from the recipient rat. In the rats treated with IABX, rhythmic beating of the grafted heart was maintained for 2 hr, whereas the untreated heart beat lasted for only 15.2 +/- 5.2 min (n = 6). In the graft hearts treated with IABX, no pathologic changes such as multiple coronary thromboses due to hyperacute rejection (HAR) were observed. Humoral immune factors (natural-IgM titer, ACH50 and CH50 complement activities, platelet count, prothrombin time (PT), activated partial thromboplastin time (APTT) and fibrinogen serum concentration), which are thought to contribute to HAR, decreased significantly following the IABX treatment. We conclude that IABX is an efficient method for prolonging the survival time of guinea pig heart xenografts by inhibiting thrombus formation in the xeno-graft heart. It was confirmed that IABX could remove recipient humoral immune factors en bloc.