Anti-ICAM-1 antibodies protect allografts against microvascular and parenchymal cell damage.

Anti-ICAM-1 (anti-intercellular adhesion molecule-1) monoclonal antibodies (CD54) were tested for treating composite tissue allografts in the rat hindlimb-cremaster transplantation model for intravital microcirculatory studies. Twenty-four transplantations were carried out across major histocompatibility barriers between Lewis-Brown Norway and Lewis rats. Isograft control transplants were compared to nontreated allograft control transplants and to allografts treated with 1 mg/kg of anti-ICAM-1 monoclonal antibodies. At 24 and 72 hours, microcirculatory vessel diameters, red blood cell velocities, functional capillary perfusion, endothelial edema index, and leukocyte-endothelial interactions were measured. At 24 and 72 hours, the number of sticking leukocytes, sticking lymphocytes, transmigrating leukocytes, and the endothelial edema index in the treated allografts were significantly decreased more than in the other 2 groups (p < .05 for all variables). Anti-ICAM monoclonal antibodies significantly reduced leukocyte-endothelial interactions, protecting the allografts from acute microvascular and parenchymal injury.