Platelet transfusion refractoriness may result from immune or non-immune platelet destruction.
Targets for clinically relevant platelet alloantibodies that can cause immune platelet refractoriness include:
- human leukocyte antigens (HLA) class I
- human platelet antigens (HPA) or in some cases high titre ABO blood group antibodies
Our lab investigates the presence of alloantibodies against HLA class I or HPA.
You should be aware that HPA antibodies in the absence of HLA class I antibodies are a rare cause of platelet refractoriness.
Making an initial request
For an initial request for HLA or HPA matched platelets you must complete our initial request form and discuss it with the Blood Tranfusion Service (BTS) or haematology registrar.
For initial testing:
- 5ml ethylenediaminetetraacetic acid (EDTA) for HLA typing
- 5ml clotted for HLA antibody screening
For patients already receiving support:
- 5ml clotted for HLA/HPA antibody screening
Depending on the antibody and typing results, both HLA class I and HPA compatible platelets can be provided.
Provision of HLA or HPA matched platelets depends on:
- Exclusion of non-immune causes of platelet refractoriness.
- Platelet refractoriness to ABO compatible single donor platelets on two or more occasions.
- Positivity for HLA class I and HPA antibodies.
A search is performed on all blood donors suitable to donate apheresis platelets who have been HLA class I and HPA typed.
If compatible HLA or HPA platelets are required, you should inform our lab and the BTS or haematology registrar as soon as possible — it can take time to call in specific donors and perform mandatory donor testing before platelets can be released.
Post infusion of HLA compatible platelets
In order to monitor the effectiveness of selected donations it is important to receive a platelet count after the transfusion.
The form can be emailed back to our lab.