Plain English Summary
Background and study aims
Some patients have blood disorders which mean they have very low numbers of platelets. Platelets are a type of blood cell important in preventing and stopping bleeding. Patients with very low numbers of platelets may need regular platelet transfusions.
One problem with needing regular platelet transfusions is that some patients may develop an immune response against transfused platelets. The immune response is controlled by human leucocyte antigens (HLA), which are proteins found on the surface of transfused platelets. The body recognises the HLA as being different to their own and makes antibodies to attack them. These patients will need platelets specially matched so their body does not recognise the platelets as being different to their own and destroy them.
The purpose of this study is to compare a new method against the current method of selecting platelets for patients who need specially matched platelets. The current method matches platelets by comparing the whole HLA. The new method will only look at a portion of the HLA, called the epitope, that is important in causing an immune response and this should provide an even closer match.
To measure the success of the study platelet transfusions we will compare the rise in the patients platelet count after each study transfusion.
Who can participate?
Adults who have aplastic anaemia (low counts of red blood cells, white blood cells and platelets) or myelodysplatic syndrome (low counts of one ore more type of blood cell) and who need regular HLA matched platelet transfusions.
What does the study involve?
You will be asked to have some extra blood tests and complete a questionnaire. You will receive platelets when they are needed. The study will collect data on a maximum of 10 transfusions. Half of these transfusions will be matched using the standard method of HLA matching and half with be matched using the new epitope method.
What are the possible benefits and risks of participating?
The epitope method of matching platelets should provide a closer match than the standard HLA method which means the transfused platelets will be less likely to be destroyed by the body.
There are no additional risks to you having platelet transfusions because the study platelets are the standard units given to patients. The only difference is that study platelets are selected to be a closer match.
Where is the study run from?
Kings College Hospital London is the lead site for this study and other large hospitals in the London area and the south east of England will take part. We may also ask hospitals in other parts of England to take part.
When is study starting and how long is it expected to run for?
The study recruited its first patient in October 2012 and will continue until the end of November 2015
Who is funding the study?
NHS Blood and Transplant
Who is the main contact?
Ms Kay Harding
Ms Kay Harding
King's College Hospital NHS Foundation Trust
125 Coldharbour Lane James Black Centre
A comparison of HLA epitope-matched with standard HLA-matched platelet transfusions in raising the platelet count increment in alloimmunised thrombocytopenic patients with aplastic anaemia or low risk myelodysplastic syndrome: A double-blind randomised crossover superiority trial
The current method of identifying HLA matched platelets for a patient is not always successful and the likelihood of finding a good donor match for patients with rarer HLA antibodies is low. Evidence from small retrospective studies suggests that matching platelets at the molecular (HLA epitope) level using a program called HLA MatchMaker gives a higher chance of a successful transfusion outcome. However, no studies have prospectively compared the effect of HLA epitope matched platelets on clinical bleeding outcomes and increase in platelet counts. Patients with aplastic anaemia or low risk myelodysplastic syndrome present and ideal group of patients as they frequently require platelet transfusions over a prolonged and often stable period, and often develop HLA antibodies.
This study has been designed to show no difference between how effective transfusion of HLA matched platelets and HLA epitope matched platelets are in increasing the patient platelet count. We predict that HLA epitope matched platelets will be more effective in increasing the patient platelet count. However, to ensure we are able to show that HLA epitope matched platelets do not give poorer platelet increments, we have used a non inferiority approach.
More details can be found at http://public.ukcrn.org.uk/search/StudyDetail.aspx?StudyID=13193
NRES Committee London Camberwell St Giles, 01 June 2012, ref: 12/LO/0695
Primary study design
Secondary study design
Randomised controlled trial
Patient information sheet
Not available in web format, please use the contact details below to request a patient information sheet
Topic: Blood; Subtopic: Blood (all Subtopics); Disease: Non-malignant haematology
Platelet transfusion: Patients will receive one study platelet transfusion eight times, on eight separate occasions. Four of the platelet bags will be chosen using the standard method of HLA matching and four will be chosen using the HLAMatchmaker programme (epitope matched platelets).
Primary outcome measures
The rise in platelet count after transfusion measured one hour after transfusion
Secondary outcome measures
1. Assessment of bleeding before and after platelet transfusion before transfusion and for 3 days after transfusion
2. Interval between platelet transfusions - The interval between the beginning of the trial transfusion until the next trial transfusion
3. Matched grade for standard HLA matched platelets
4. Number of epitope mismatches for epitope matched platelets
5. Reactions to trial platelets within 24 hours of transfusion
6. Rise in platelet count 24 hours after transfusion
7. Rise in platelet count after transfusion taking into account the platelet dose and patient body size at 1 and 24 hours
Overall trial start date
Overall trial end date
Participant inclusion criteria
1. Age 16 years or older
2. Patients with aplastic anaemia or low-risk myelodysplastic syndrome
3. Patients who do not benefit from random (non-selected) donor platelet transfusions
4. Patients who require regular platelet transfusions according to local and British Committee for Standards in Haematology (BCSH) guidelines
5. Patients with evidence of HLA antibody(ies)
6. Patients that are expected to require multiple HLA selected prophylactic platelet transfusions
Target number of participants
Planned Sample Size: 40; UK Sample Size: 40
Participant exclusion criteria
1. Patients with significant and palpable splenomegaly (enlargement of the spleen)
2. Patients who do not have serum HLA antibodies
3. Patients receiving anti-thymocyte globulin (ATG) treatment, specifically for the 5 days of ATG treatment and for the 14 days after ATG treatment. Once recovered from the treatment, the patient would be eligible to participate in the trial.
4. Patients who have previously participated in this study
5. Women who are pregnant or lactating
6. Patients unable to give written informed consent or comply with the protocol
Recruitment start date
Recruitment end date
Countries of recruitment
Trial participating centre
NHS Blood and Transplant (NHSBT) (UK)
Funding Body Type
Funding Body Subtype
Results and Publications
Publication and dissemination plan
Not provided at time of registration
Intention to publish date
Participant level data
Not provided at time of registration
Results - basic reporting