From the Guidelines
Delayed hemolytic transfusion reactions (DHTR) are primarily caused by antibodies to Rh (D, C/c, E/e) and K, as well as other blood group antigens, which can result in clinically significant hemolysis. These antibodies can develop against foreign red blood cell antigens following a blood transfusion, and their presence significantly increases the risk for acute or delayed hemolytic transfusion reactions (HTRs) 1. The most common specificities identified in patients with sickle cell disease, a population at high risk for red cell alloimmunization, include antibodies to Rh and K 1.
Key Antibodies Involved in DHTR
- Antibodies to Rh (D, C/c, E/e)
- Antibodies to K
- Other blood group antigens, although less common, can also be involved in DHTRs, including those in the Kidd, Duffy, and Kell systems. However, the evidence from 1 highlights the prominence of Rh and K antibodies in the context of sickle cell disease, a condition with one of the highest incidences of red cell alloimmunization.
Clinical Implications
The presence of these antibodies not only makes it challenging to find compatible red cell units for transfusion but also poses a significant risk for hemolysis, which can be associated with considerable morbidity and mortality 1. Therefore, preventing red cell alloimmunization or reducing the formation of red cell alloantibodies is a critical goal in the management of patients at risk for DHTRs.
Management Considerations
Management of DHTR involves stopping further incompatible transfusions, providing supportive care, and ensuring that future transfusions are compatible with the newly identified antibodies. This approach is crucial for preventing further hemolysis and improving patient outcomes, particularly in populations with high risks of red cell alloimmunization, such as those with sickle cell disease 1.
From the Research
Antibodies Involved in Delayed Hemolytic Transfusion Reaction (DHTR)
- The antibodies involved in DHTR are often RBC alloantibodies, which can be identified in most cases 2.
- However, in up to one-third of cases, no new RBC alloantibodies can be identified posttransfusion 2.
- In some cases, weakly reactive antibodies or new allo-antibodies possibly responsible for the delayed hemolytic reaction may be found 3.
- The presence of anti-C5 inhibition has been reported to be effective at mitigating hemolysis in the setting of some severe DHTRs, suggesting a role for complement in the pathogenesis of DHTRs 2.
- Other antibodies, such as anti-M antibodies, can also cause acute hemolytic transfusion reactions, but their role in DHTR is less clear 4.
Complexity of DHTR Pathophysiology
- The pathophysiology of DHTR is complex and not fully understood, with multiple factors contributing to the reaction 3, 2.
- The initial symptoms of DHTR can be non-specific and may mimic other complications of sickle cell disease, making diagnosis challenging 3, 5.
- The involvement of complement and other immune mechanisms in DHTR highlights the need for further research into the underlying causes of this reaction 2, 6.