Greater Care Needed Over Transfusions in Sickle Cell Disease

Liam Davenport

April 06, 2022

MANCHESTER — Over a fifth of reported blood transfusion reactions are in patients with sickle cell disease, over half of which involve the potentially life-threatening complication hyperhaemolysis, suggests a UK analysis.

"Haemolytic transfusion reaction is a very serious complication," said Dr Joe Sharif, Manchester University NHS Foundation Trust, presenting at analysis of Serious Hazards of Transfusion (SHOT) data for 2010–2019.

Potential risk factors were being female, urgent transfusion and "historical alloimmunisation", or the formation of antibodies to antigens from another human, Dr Sharif told the British Society for Haematology (BSH) 62nd Annual Scientific Meeting on April 5.

With the data also revealing a mortality rate of 5%, Dr Sharif said that transfusion in sickle cell disease should be considered carefully, and avoiding alloimmunisation "should be a priority".

Speaking to Medscape UK, Dr Sharif said, while they "haven’t looked at the total number" of blood components given to sickle cell disease patients across the UK, it would be "good" to compare it with the number of transfusion reactions.

However, he underlined that "what we do know is that 22% of all the reports of haemolytic transfusion reactions are in sickle cell disease", which is a "significant" proportion.

Giving Transfusions Requires 'Careful Consideration'

Session chair Dr Simon Stanworth, Professor of Haematology and Transfusion Medicine, University of Oxford, added that the yearly analysis of sickle cell disease transfusion reaction data by SHOT "continues to be important".

This is particularly in the context of randomised trials of red cell transfusions with liberal versus restrictive strategies, but more "fundamentally, it’s about harm".

"What are the risks of harm? We need to have a good understanding of what that means."

Dr Stanworth asked Dr Sharif to explain further the idea that giving transfusions requires "careful consideration". Dr Sharif replied that the SHOT report shows that "transfusions may be given for an inappropriate reason", due to a "lack of education" among staff, which results in them being given for reasons that are "not in the guidance".

He highlighted the BSH guideline for transfusion in sickle cell disease, and said local teams should speak to specialists "to get advice on when the transfusion is necessary". In addition, there "needs to be a discussion with the patient" to make sure they are "aware of the potential risks".

"Once the patient develops alloimmunisation, they are at higher risk and that can have serious implications for their future," such as when they might need a transfusion for surgery or in an emergency, and it "might be more difficult to transfuse them" as a result.

Number of Transfusion Reactions Increases 'Year-on-Year'

Dr Sharif began by saying that the number of reports of transfusion reactions to SHOT has increased "year-on-year".

He said that, in sickle cell disease, transfusions are given to treat and prevent the progression of acute complications, and for their primary and secondary prevention, but this must be weighed against the risk of red cell alloimmunisation, haemolytic transfusion reactions, and iron overload.

Sickle cell disease patients are at increased risk of complications, potentially due to ethnic variations in red cell antigens in both the donor and the recipient, and may experience hyperhaemolysis, which causes severe pain, low-grade fever, jaundice and haemoglobinuria.

Dr Sharif explained that a common reason for reactions is the specific requirements for transfusion not being met. These include:

  • An extended red blood cell phenotype using a pre-transfusion blood sample

  • The receipt of fully Rhesus- and Kell-matched units to reduce the risk of alloimmunisation

  • In patients with a history of alloantibodies, the receipt of units negative for the relevant antigen

To investigate further, the team examined all reports to SHOT between 2010 and 2019, finding that of 424 haemolytic transfusion reactions, 93 (21.9%) were in sickle cell disease.

Dr Sharif showed that the mean age at which patients experienced haemolytic transfusion reactions was 31 years, at a range of 8-74 years, and 76% were in women.

The majority (n=78) were delayed reactions, occurring a mean of 9 days after the transfusion, and 66% occurred on an urgent, rather than elective, basis.

The transfusions were given for anaemia in 29% of cases, followed by for surgery in 17%, vaso-occlusive crisis in 13%, and acute chest syndrome in 10%. The clinical features experienced by patients were primarily pain, fever and haemoglobinuria.

Previous alloimmunisation was recorded for 40% of patients, and 8% had experienced a previous haemolytic transfusion reaction. In addition, 3% had a history of hyperhaemolysis.

Antibody screening revealed that 44% of patients had a new alloantibody following their transfusion, rising to 47% in patients with a delayed haemolytic reaction.

Fifty patients experienced hyperhaemolysis, the majority (n=44) in the context of a delayed reaction, and five patients died.

Among patients with hyperhaemolysis, previous alloimmunisation was seen in 42% versus 37% among those without hyperhaemolysis, and 14% of those with hyperhaemolysis versus 0% without hyperhaemolysis had experienced a previous haemolytic transfusion reaction.

In contrast, 28% of patients with had a new alloantibody versus 60% among those without hyperhaemolysis.

No funding declared.

Sharif declares relationships with Novartis, GBT, Emmaus Medical.

No other relevant relationships declared.

British Society for Haematology 62nd Annual Scientific Meeting: Abstract BSH22-OR23. Presented April 5.

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