RH Genotype Matched RBC Transfusions (RBC)

To determine the feasibility of matching donor red cells by RH genotype for a cohort of chronically transfused patients with SCD.

This is a pilot feasibility study in patients with Sickle Cell Disease requiring chronic red cell transfusions. RH genotyped donor units will be obtained from the New York Blood Center. Patients will be matched with donor units whose RH genotypes predict no foreign Rh protein exposure to the patient. This will provide red cell matching at a level above the current standard of care (serologic C, E, and K matching). Patients will receive RH matched red cells for the duration of their chronic transfusion therapy or up to five years, whichever is shorter. It will then be determined whether sufficient RH matched donor units can be identified for the patient's RH genotype. Although not powered to determine effectiveness, all patients's Rh alloantibody formation will be monitored. For subjects with a history of stroke/recurrent transient ischemic attack or other indication who require tight control of Hb S, and RH genotyped blood is not available, standard of care serologic matched blood would be administered rather than delaying transfusion and risking higher Hb S level. For all subjects, standard of care serologic matched blood would be administered rather than delaying transfusion beyond 7 days.

Subjects will receive RH genotype matched red cell units for transfusion. For subjects with a history of stroke/recurrent transient ischemic attack or other indication who require tight control of Hb S, and RH genotyped blood is not available, standard of care serologic matched blood would be administered rather than delaying transfusion and risking higher Hb S level. For all subjects, standard of care serologic matched blood would be administered rather than delaying transfusion beyond 7 days

Subjects will receive RH genotyped matched red cell units for transfusion in addition to standard serologic C, E, and K antigen matching and being hemoglobin S negative, which is our institutional standard of care for patients with Sickle Cell Disease.

Patients will be provided with red cell units that are C, E, and K antigen matched (standard of care for patients with SCD) and genotype matched at the RHD and RHCE loci.

The primary objective of this study is to determine the feasibility of RH genotype matched red cells for chronically transfused patients with SCD. Approximately 20 RHD (Rhesus D) and 20 RHCE (Rhesus CE) variants have been observed in patients with SCD, and will determine whether sufficient RH genotyped units can be matched to the patient's own RH genotype.

The secondary objective is to determine if there is a relationship between providing RH genotype matched red cell units to Rh alloimmunization. Although not powered to determine effectiveness, our secondary objective is to monitor for Rh alloimmunization.

Inclusion Criteria: Subjects age >12 months Diagnosis of SCD, all genotypes Require a period of chronic red cell transfusion therapy Exclusion Criteria: Rare RH genotype that would preclude identification of sufficient RBC units Antigen negative requirements due to alloimmunization that would preclude identification of sufficient RBC units Alloimmunized to D antigen Rh alloimmunized patients for whom providing RH genotype matched blood would expose the patient to an antigen that would not be consistent with standard of care and blood bank protocols

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