Alloimmunization to red cell antigens in liver and multivisceral transplant patients.
ABSTRACT 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.
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.
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.
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.
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ABSTRACT: Background The Diego blood group presents a major polymorphic site at Residue 854, causing a proline (Dib antigen) to leucine (Dia antigen) substitution. Dia alloimmunization has been observed among Asian and Native South American populations. Considering that Brazilians represent a genetically diverse population, and considering that we have observed a high incidence of Dia alloimmunization, we typed HLA-DRB1 alleles in these patients and performed in silico studies to investigate the possible associated mechanisms.Study Design and Methods We studied 212 alloimmunized patients, of whom 24 presented immunoglobulin G anti-Dia, 15 received Di(a+) red blood cells and were not immunized, and 1008 were healthy donors. HLA typing was performed using commercial kits. In silico analyses were performed using the TEPITOPEpan software to identify Diego-derived anchor peptide binding to HLA-DRB1 molecules. Residue alignment was performed using the IMGT/HLA for amino acid identity and homology analyses.ResultsHLA-DRB1*07:01 allele was overrepresented in Dia-alloimmunized patients compared to nonimmunized patients and to healthy donors. Two motifs were predicted to be potential epitopes for Dia alloimmunization, the WVVKSTLAS motif was predicted to bind several HLA-DR molecules, and the FVLILTVPL motif exhibited highest affinity for the HLA-DRB1*07:01 molecule. Pocket 4 of the DRB1*07:01 molecule contained specific residues not found in other HLA-DRB1 molecules, particularly those at Positions 13(Y), 74(Q), and 78(V).Conclusion Individuals carrying the HLA-DRB1*07:01 allele present an increased risk for Dia alloimmunization. The identification of susceptible individuals and the knowledge of potential sensitization peptides are relevant approaches for transfusion care, diagnostic purposes, and desensitization therapies.Transfusion 05/2014; 54(10). DOI:10.1111/trf.12652 · 3.57 Impact Factor
ISBT Science Series 10/2009; 4(n2):230 - 235. DOI:10.1111/j.1751-2824.2009.01278.x
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ABSTRACT: BACKGROUND AND OBJECTIVES: Red cell antibodies may complicate blood provision and liver transplantation outcome. The aim of this survey was to document red cell antibodies in adults undergoing liver transplantation and make recommendations for clinical practice. MATERIALS AND METHODS: We completed a 10-year retrospective review of adults undergoing liver transplant, in a single UK centre using 4- to 6-weekly red cell antibody screening. RESULTS: Seven hundred and thirty seven patients were reviewed: 58 (7·9%) had antibodies. In 50 (6·8%) patients, the antibodies were clinically significant, and the commonest were Rhesus (49·5%) and Kell (11%). 33 patients had a single antibody, and the rest had multiple antibodies (range 2-5). Two-thirds of patients (38) had antibodies at presentation; 22% of these developed additional antibodies while on the waiting list or postoperatively. CONCLUSION: Consideration should be given to the proactive use of Rh- and K-typed blood in end-stage liver disease in order to reduce alloimmunization. In addition, regular antibody screening would enable staff to identify those with atypical antibodies and plan their transfusion support.Vox Sanguinis 06/2013; 105(4). DOI:10.1111/vox.12059 · 3.30 Impact Factor