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

This is a Phase 1/2 trial 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 three years, whichever is shorter. In the pilot phase, we have determined it is feasible to identify RH matched donor units for the patient's RH genotype for every scheduled transfusion. We will now continue to show feasibility as well as determine efficacy by monitoring Rh alloantibody formation.

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.

Inclusion Criteria:

• Subjects age >6 months
• Diagnosis of SCD, all genotypes
• Require a period of chronic red cell transfusion therapy
• Subject/parental/guardian permission (informed consent) and if appropriate, child assent

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
• Parents/guardians or subjects who, in the opinion of the Investigator, may be non-compliant with study schedules or procedures

Protected Health Information (PHI) will be shared with the New York Blood Center (NYBC) to order blood for the subjects. This will be done using a secure online blood ordering system. The NYBC uses an FDA-approved HIPAA secure system called Blood Enterprise Computer System (BECS) to store patient data and results, including PHI. 3rd party computers at New York Blood Center will also store study data using study identification (ID) numbers. The purpose of having study data coded at NYBC is for specialized testing for red antigens or antibodies for which we will provide some clinical data to assist in the laboratory evaluation. To assure that the transmission of data and samples maintains confidentiality we will used study ID numbers for these samples. The master list will be maintained at the Children's Hospital of Philadelphia (CHOP). The study databases are password protected and on password protected computers at CHOP and at NYBC, that are backed up on the research servers.

For the duration of the study

Only study team members will have access to the data.