The Department of Public Health and Primary Care at the University of Cambridge was awarded a grant to set-up the National Institute for Health Research (NIHR) Blood and Transplant Research Unit (BTRU) in Donor Health and Genomics (Director: Professor Emanuele Di Angelantonio). The BTRU is a strategic collaboration led by Cambridge in partnership with the Wellcome Sanger Institute, the University of Oxford and NHS Blood and Transplant (NHSBT). The Unit addresses major questions about the health of blood donors and produces evidence-based strategies to improve donor safety and to ensure a steady supply of blood to the NHS (thus informing NHSBT). We research:
- Blood cell traits
- Causes of potential adverse health consequences of blood donation
- Personalised strategies to blood donation
The BTRU is the umbrella for two large studies: INTERVAL and COMPARE. Blood donors that participated in these studies gave consent for their samples to be stored and used for research purposes. The data derived from these samples comprise the INTERVAL BioResource and the COMPARE BioResource. There are numerous research projects utilising data from these studies.
In the UK, men donate blood every 12 weeks and women donate every 16 weeks. But why do we follow these intervals? In over 100 years of blood donation practice, INTERVAL is the first-ever trial to assess the impact of varying the frequency of blood donation on donor health and the blood supply.
INTERVAL recruited 45,000 blood donors. Men were randomly assigned to donate blood at 8-week, 10-week and 12-week intervals and women were randomly assigned to donate blood at 12-week, 14-week and 16-week intervals. Samples were collected and donors were asked to complete health questionnaires.
Results from INTERVAL have shown that more frequent blood donations from donors can be done without causing harm to donor health. These findings have provided policy-makers (NHSBT) with evidence that more frequent collection from donors than is now standard can be done over two years without causing harm to donor health, allowing better management of the supply to the NHS of units of rare blood groups.
To help protect the health of donors, it’s a requirement to find out whether a donor’s blood haemoglobin levels are adequate. Haemoglobin is an iron-containing protein found in red blood cells that carries oxygen around the body. Blood donor services have to measure haemoglobin levels in advance of each blood donation to protect the health of donors (e.g., to prevent anaemia) and to ensure the quality of blood products.
NHSBT measures the haemoglobin levels of donors by placing a drop of donor’s blood into a copper sulphate solution. If the drop sinks sufficiently, then it is judged that the donor’s haemoglobin levels are high enough to donate. If the drop doesn’t sink sufficiently, then a more accurate and costly test is used (‘HemoCue’). Alternative methods used by other blood services may be more accurate, donor-friendly and less time consuming. However, their comparative merits—and methods used by NHSBT—had not been thoroughly investigated until the COMPARE study. Results from this study will help to shape NHSBT (and international) policy concerning haemoglobin screening.
Discovering Blood Group Type
How many blood groups are there? We used to think four—O, A, B and AB. Then we discovered that red blood cells sometimes have another antigen (a protein molecule) called the RhD antigen. If this is present, then your blood group is RhD positive (+); if not present then RhD negative (-). So, there are eight blood groups—O (+/-), A (+/-), B (+/-) and AB (+/-).
We now know that there are more than 300 red blood cell antigens and 33 platelet (bone marrow cells) antigens that differ between individuals. Patients receiving multiple transfusions will thus receive slightly different blood types and build a sensitisation to a variety of antigens. Over time, this will limit which blood they can receive for a transfusion. Differences in the blood can also cause prenatal complications.
In collaboration with investigators from Brigham and Women’s Hospital and Harvard Medical School, we have developed and validated a computer program that can comprehensively and cost-effectively determine blood group type with more than 99% accuracy. The study represents one of the first applications of using genomic (genes in an organism) information for routine clinical benefit.