Low rate of Rhesus immunization from Rh-incompatible blood transfusions during liver and heart transplant surgery.

Transfusion of one unit or more of Rh-positive red blood cells normally causes circulating anti-D antibody to appear 2-6 months later in 80-95% of Rh- persons. We asked whether transplant immunosuppression with cyclosporine and corticosteroids affects Rh immunization. Nineteen Rh- liver, heart, and heart-lung transplant recipients received 3-153 (median: 10) units of Rh+ RBCs at surgery and were tested for anti-D greater than 2 months later. Three patients developed anti-D at 11-15 days; one may have had an unusually rapid primary immune response and two were secondary to previous exposure by pregnancy. None of the other 16 patients had anti-D when tested 2.5-51 months later (13 patients, greater than 11.5 months). This low rate of Rhesus immunization in association with cyclosporine immunosuppression allows greater flexibility in meeting the transfusion needs of Rh- liver and heart transplant patients. Caution is still advised in young females and in patients who may have been previously exposed to Rh+ RBCs by transfusion or by pregnancy prior to the availability of perinatal Rh immune globulin twenty years ago. Other humoral immune responses to some vaccines or infectious agents may also be impaired in transplant patients.

Red cell antibody problems in 1000 liver transplants.

Liver transplant patients frequently require large amounts of blood. The frequency and nature of their red cell (RBC) antibody problems were examined. Records were reviewed in 496 adults and 286 children undergoing 1000 consecutive transplants. Twenty-two percent of adults and 14 percent of children had RBC alloantibodies. Antibodies of potential clinical significance were found before transplant in 6.3 percent of adults and 1.0 percent of children; despite immunosuppression, they appeared 1 to 5 weeks after transplant in an additional 7.5 and 5.2 percent respectively. These antibodies probably represented secondary immune responses. Of 58 transplant patients with prior potentially significant antibodies, 8 required 7 to 110 units of antigen-untyped blood after 8 to 28 units of antigen-negative blood; of these patients, one had subsequent hemolysis. Positive direct antiglobulin tests in 24 percent of adults and 10 percent of children were most often thought to be due to nonspecific adsorption of IgG. Anti-recipient ABO antibodies developed in 22 of 60 (37%) evaluable ABO-unmatched grafts; 13 cases had associated hemolysis. In all, 36 percent of adults and 20 percent of children had diverse RBC antibody problems. Resolution of these problems is an important part of the laboratory support necessary for a liver transplantation program.