Duke University Hospital, North Carolina, United States
Background/Case Studies: Sickle Cell Disease (SCD) patients are at high risk of forming RBC alloantibodies, particularly to the Rh blood group, due to mismatch in the demographics of SCD patients and blood donors in the US. If these antibodies are not recognized, delayed hemolytic transfusion reactions and hyperhemolytic reactions may occur, which can be fatal. We have 3 patients that have been transitioned to receiving RH genotype matched RBCs after hemolytic crises and report here on their clinical course.
Study
Design/Methods: Retrospective chart review was performed to collect data related to transfusion and clinical outcomes. Bioarray Human Erythrocyte Antigen (HEA) gene chip (Immucor DX, Grand Rapids, MI) is performed in house, and further RH molecular testing is performed by reference laboratories as indicated.
Results/Findings: All 3 patients are females with HbSS disease. Patient 1 was known at outside hospital to have significant alloimmunization and would only receive RBC transfusion at academic medical centers. After receiving a phenotype matched, crossmatch compatible unit for acute chest syndrome with hgb 4.5 g/dl (baseline 7g/dl), she experienced hemolytic reaction 10 days later with nadir to 3.8 g/dl. An HTLA antibody was identified, but due to incompatible crossmatches, efforts were made to find a RH genotype matched donor who was also negative for the other known antibodies. One donor in the US was identified and she has successfully been transfused 4 times over the past 5 years. Patient 2 had been on simple RBC transfusion treatment since 2020 for secondary stroke prophylaxis, when new antibodies were detected in 2022. Due to panagglutinin with anti-D like specificity in eluate, RH molecular analysis was performed. As the RHCE genotype was relatively straight forward, the decision to request RH genotype matched RBCs was made. The patient has continued to receive 2 RBCs monthly without event. Patient 3 had an anti-D and warm autoantibody with -e like specificity identified during her first pregnancy. She received 6 RBCs during that pregnancy without event. During her second pregnancy the following year, she developed a sickle cell crisis at 24 weeks gestation with 2 g/dl drop in hgb at which time it was decided to try RH matching RBC units after poor transfusion response to 4 units of D-,C- negative RBCs. She received 1 RBC unit at delivery with good response. Conclusions: RH genotype matching of RBCs is becoming more feasible as testing of blood donors becomes more prevalent. Future areas of study should include standardizing RH genotyping in at risk patients and data management to improve labeling and matching of genotyped RBC units.
Importance of research: Molecular typing is becoming more common and is the future of precision medicine, particularly for transfusion dependent patients.
