Recovery and survival of stem cell originated red cells

INTERVENTION: Setting: 1. Units of whole blood will be donated in the East Anglian region static or mobile donor clinics/sessions 2. Red cells will be produced from whole blood donations in licensed facilities at NHSBT Bristol (Filton) 3. Red cells will be radiolabelled with 51Cr in the Radiopharmacy Unit, Guy's Hospital, London 4. Recipients will receive infusions of radiolabelled RBCs in the Wellcome Trust/NIHR Clinical Research Facility at Addenbrooke’s Hospital, and follow up blood samples will be taken at their home or place of work, according to their preference Interventions to be compared: Red blood cells manufactured from adult haematopoietic stem cells (mRBC) Comparator: standard donated red blood cells (sRBC) Selection of participants: Potential donor participants born after 1st January 1996 with an extended blood group phenotype available were identified anonymously. Potential recipients were sought from the Cambridge Bioresource (CBR) as part of the RESTORE‐i feasibility trial. Potentially eligible members of the CBR were approached by the CBR team for their permission for the RESTORE study team to contact them to discuss their participation in this clinical trial. To be potentially eligible for the trial, donors and recipients must be willing to participate, and also be blood group compatible with potential recipients or donors. Once the panel of blood compatible Donors and Recipients has been identified as part of the RESTORE‐i feasibility, groups of blood phenotype matched donors and recipients will be selected, with donors with the highest CD34+ (haematopoietic stem cell) counts selected as a preference. Each group will consist of a minimum of 1 donor and 2 recipients to ensure availability of recipients for the mRBC and avoid wastage. S CONDITION: Blood transfusion ; Not Applicable SECONDARY OUTCOME: Post‐transfusion recovery of Red Blood Cells at 24 hours (PTR24) is measured by calculating the proportion of red blood cells infused that remain in the circulation at 24 hours following infusion PRIMARY OUTCOME: ; Co‐primary outcome measures:; 1. Safety as assessed by:; 1.1. Serological detection of new red cell alloantibodies against standard and/or manufactured red blood cells at 120 days after the first infusion of red blood cells and at up to 180 days after the second infusion of red blood cells.; 1.2. Description of all serious adverse reactions that occur from day of infusion of RBCs until up to 180 days after the second infusion of red blood cells.; 2. Survival of Red Blood Cells is measured as the time it takes for 50% of the radiolabelled RBCs to be cleared from the circulation (T50). Blood samples are taken at 5, 7.5, 10, 12.5, 15, 30 and 60 minutes post transfusion of the radiolabelled RBCs and then at 24 hours and then on days 2, 3, 7, 14, 21, 28, 35, 42, 49 75, 100 and 120.; INCLUSION CRITERIA: Participant Inclusion Criteria (blood donors) Blood donors must satisfy all the following criteria to be eligible for the study: 1. Born after 1st January 1996 2. Able to donate whole blood 3. Fulfil all requirements to donate whole blood for transfusion according to UK Blood Services definition at the time of donation 4. Previous successful whole blood donation 5. Willing to consent to their blood donations being used for the trial, including scheduling donation appointments to suit the needs of the trial Participant Inclusion Criteria (recipients) The participants (recipients) must satisfy all the following criteria to be eligible for the study: 1. Over 18 years of age 2. In good general health 3. Female and of no child‐bearing potenti