Alloimmunization to red cell antigens in liver and multivisceral transplant patients.

Background: Alloimmunization to red blood cell (RBC) antigens can significantly impact transfusion support of patients undergoing solid-organ transplantation. This study evaluated the incidence of clinically significant RBC alloantibodies (abs) in 2000 consecutive adults receiving liver (OLTX), intestinal (ITX) or multivisceral (MVT) transplants.
Methods: From January 1991 to May 2006, 2000 patients underwent OLTX (n=1892), MVT (n=74), or ITX (n=34). Blood sample for serologic investigation was submitted to the transfusion service no later than 4 hr before surgery. The presence of clinically significant RBC abs before transplant with subsequent transfusion requirements, the incidence of delayed transfusion reactions, and de novo abs after transplant were evaluated.
Results: One hundred fifteen patients (5.75%) had clinically significant RBC abs before transplant, with 56.7% directed against Rh system antigens. Forty-six (40%) had multiple abs. A mean of 18 packed RBC units (U) were transfused per patient. Patients requiring >20 U (n=34) or those with multiple abs received antigen-negative units for the first 5-10 U when antibody was still present, switched to antigen-unscreened units during massive blood loss and returned to antigen-negative units for the last 5-10 U transfused. Twelve patients (0.6%) developed de novo abs posttransplant. Twenty-two (1.1%) had delayed serologic transfusion reaction. All patients were successfully managed without delay in initiation of surgery or hemolytic complications.
Conclusion: RBC alloimmunization can present a special challenge to solid-organ transplantation. Early serologic testing of the recipient pretransplant and prompt communication between the transfusion service and transplant team facilitates successful transfusion management of these patients.