Abstract

Background: Thalassemia is a common inherited hemoglobin disorder in Malaysia. Regular transfusions of packed red cells are required to treat transfusion-dependent thalassemia. These transfusions, although lifesaving, may lead to complications such as red blood cell (RBC) alloantibody formation. This study aimed to determine the incidence of RBC alloantibodies in thalassemia patients who regularly received blood transfusions at our center.

Methods: This study included 33 thalassemia patients who received regular transfusions at Dungun Hospital, Terengganu, Malaysia, from 2017 to 2023. Laboratory data and clinical presentation information were obtained. Antibody screening was conducted to identify potential alloantibodies that could react with donor blood. All samples that tested positive for alloantibodies were investigated further to determine antibody specificity.

Results: The rate of RBC alloimmunization in the studied thalassemia patients was 36.4%. Six alloantibodies were detected in the patient cohort, with some individuals developing antibodies of single or multiple specificities. The most frequently present alloantibodies were against the Rh blood group system.

Conclusion: The development of alloantibodies related to blood transfusions can create challenges in managing transfusion-dependent thalassemia patients. It is advisable to incorporate extended-matched phenotyping into care protocols to mitigate the risk of alloimmunization and minimize the chances of these patients developing blood transfusion-related alloantibodies.

Introduction

Thalassemia is a most common autosomal recessive disorder that affects a significant proportion of the population in tropical countries like Malaysia. As per current estimates, around 6.8% of Malaysians are thalassemia carriers, which puts them at risk of developing anemia to varying degrees1. Hb E thalassemia and beta thalassemia are the predominant inherited hematological disorders of beta-globin in Malaysia2, 3.

Patients with severe thalassemia rely on blood transfusions every 3–4 weeks to treat anemia4.According to the current guidelines of the Thalassemia International Federation, blood transfusions are recommended for pre-transfusion Hb levels of 9–10 g/dL in patients with transfusion-dependent thalassemia5. Recent studies have shown that the incidence of red cell alloantibodies is higher among thalassemia patients than in the general population, which could be attributed to the frequent blood transfusions required by thalassemia patients6.Such alloantibodies arise when the immune system recognizes surface antigens on donor RBCs as foreign, thereby triggering the production of antibodies targeting these antigens4.

The existence of alloantibodies can add complexity by delaying the process of matching blood for transfusion and potentially increasing the risk of hemolytic transfusion reactions. Managing these risks during transfusions becomes even more challenging when autoantibodies coexist with alloantibodies7.

Thalassemia patients need to be closely monitored for the development of alloantibodies, as this can increase the risk of transfusion reactions and make it more difficult to find compatible blood for future transfusions. Regular blood tests and screening for alloantibodies should be performed to ensure the safety and effectiveness of transfusions for thalassemia patients.

Hence, this study aimed to (1) determine the incidence of RBC alloantibodies and (2) identify the types of alloantibodies among thalassemia patients who received regular blood transfusions at our center, Dungun Hospital, Terengganu, Malaysia. Knowing the incidence of alloantibodies among thalassemia patients will assist clinicians and transfusions in predicting the level of difficulty in searching for compatible blood.

Table 1.

Demographic and clinical characteristics of the patients

Demographic data Frequency Percentage Gender Male 14 42.4 Female 19 57.6 Age 12 36.4 12 – 18 years 7 21.2 >18 years 42.4 Diagnosis Beta thalassemia major 11 33.3 Alpha thalassemia 3 9.1 Hb E Beta thalassemia 15 45.5 Hb Adana Pakse 2 6.1 Beta thalassemia trait with ESRF 1 3.0 Hb H Constant Spring 1 3.0 Numbers of transfusions 20 60.6 51 - 100 11 33.3 101 - 150 1 3.0 >150 1 3.0 Blood group A 8 24.2 B 8 24.2 AB 4 12.1 O 13 39.4 × Figure 1 . Antibody screening result for thalassemia patients who received blood transfusion (n = 33) . Figure 1 . Antibody screening result for thalassemia patients who received blood transfusion (n = 33) .

Table 2.

The alloantibody specificities in immunized patients (n=12)