# Investigation of Delayed Transfusion Reactions in Sickle Cell Disease Patients Polytransfused in the Brazilian Amazon

## TL;DR

This study examines delayed transfusion reactions in sickle cell disease patients in the Brazilian Amazon who have received multiple blood transfusions.

## Contribution

The study provides insights into the frequency and types of delayed transfusion reactions in polytransfused sickle cell disease patients in a specific geographic and ethnic population.

## Key findings

- 20.5% of patients showed alloimmunization reactions with various anti-Rh antibodies.
- 44.4% of patients with alloimmunization also had autoantibodies.
- 54.4% of patients exhibited clinical and laboratory indicators of delayed hemolytic reactions.

## Abstract

Background: Sickle cell disease (SCD) affects approximately 100,000 people in the United States and millions worldwide, with the highest prevalence of 70% of SCD being found in individuals of African ethnicity. Delayed hemolytic, alloimmunization, and anamnestic transfusion reactions in multiple transfusion patients need to be investigated and managed to avoid a worsening of the patient’s clinical status. Objective: This paper aims to investigate delayed transfusion reactions in SCD patients who were polytransfused in the Brazilian Amazon. Material and Methods: The clinical and laboratory indicators of SCD patients with more than four transfusions were investigated. The patients were treated at the Fundação Hospitalar de Hematologia e Hemoterapia do Estado do Amazonas, Brazil. Results: A total of 44 polytransfused patients with SCD were followed. Regarding Rh phenotype, it was possible to observe a frequency of 26.6% (12) patients with the RZRZ (DCE/DCE) phenotype, in addition to 4.5% (two) patients with RH and RHCE variants. It was also possible to observe 20.5% (nine) patients with an alloimmunization reaction, who presented the following alloantibodies: anti-RhD, anti-E, anti-K, anti-Jkb, anti-N, anti-S, and anti-Dia, two of which are unidentified. Of these, four (44.4%) patients also presented autoantibodies, anti-e, and three unidentified antibodies, and four (44.4%) patients presented an anamnestic reaction, with anti-RhD, K, and Jkb antibodies. Of the 44 patients monitored, 54.4% (24) had clinical and laboratory indicators of a delayed hemolytic reaction. Conclusion: Delayed transfusion reactions, often neglected, occur frequently. Therefore, transfusions need to be monitored for at least 28 days, with medical investigation of clinical and laboratory indicators to make greater use of this therapeutic resource.