Les anémies aiguës et la stratégie transfusionnelle chez les drépanocytaires adultes: Acute anemias transfusion strategy in adult sickle cell patients.

Worsening of anemia is very common in sickle cell disease. It is important to investigate specific complications related to sickle cell disease but also other causes of anemia in general. Transfusions or exchange transfusions are major therapeutic options and are frequently used for acute complications of sickle cell disease but also for primary and secondary prevention of some of the chronic complications. The transfusion strategy has been modified since the awareness of post-transfusion hemolysis by taking into account the transfusion risk score. A strong collaboration between the patient's expert center, the Blood center and the patient's hospitalization unit is required to make decisions. © 2023 Société nationale française de médecine interne (SNFMI). Published by Elsevier Masson SAS. All rights reserved.

Delayed hemolytic transfusion reaction in the French hemovigilance system.

In France, reporting of adverse events related, or likely to be related, to transfusion is mandatory. Since its creation in 1993, the French hemovigilance system has contributed to a better recognition of unappreciated risks like delayed hemolytic transfusion reactions (DHTR) in sickle-cell disease (SCD) patients. Long under-reported or misclassified, reports of this serious complication of transfusion have improved, particularly through the dissemination of information within the hemovigilance network. To our knowledge, the French hemovigilance system has one of the largest series of DHTR in SCD patients. Guidelines for diagnosis and reporting to hemovigilance system as well as a specific reporting form are being developed, which should contribute to the quality of data essential for epidemiological studies.

Complement activation during intravascular hemolysis: Implication for sickle cell disease and hemolytic transfusion reactions.

Intravascular hemolysis is a hallmark of a large spectrum of diseases, including the sickle cell disease (SCD), and is characterized by liberation of red blood cell (RBC) degradation products in the circulation. Released Hb, heme, RBC fragments and microvesicles (MVs) exert pro-inflammatory, pro-oxidative and cytotoxic effects and contribute to vascular and tissue damage. The innate immune complement system not only contributes to the RBC lysis, but it is also itself activated by heme, RBC MVs and the hypoxia-altered endothelium, amplifying thus the cell and tissue damage. This review focuses on the implication of the complement system in hemolysis and hemolysis-mediated injuries in SCD and in cases of delayed hemolytic transfusion reactions (DHTR). We summarize the evidences for presence of biomarkers of complement activation in patients with SCD and the mechanisms of complement activation in DHTR. We discuss the role of antibodies-dependent activation of the classical complement pathway as well as the heme-dependent activation of the alternative pathway. Finally, we describe the available evidences for the efficacy of therapeutic blockade of complement in cases of DHTR. In conclusion, complement blockade is holding promises but future prospective studies are required to introduce Eculizumab or another upcoming complement therapeutic for DHTR and even in SCD.

[Delayed haemolytic transfusion reaction: About 3 patients with sickle cell disease]. / L'hémolyse post-transfusionnelle retardée : à propos de 3 patients drépanocytaires.

INTRODUCTION: The use of a red blood cell transfusion in a patient with major sickle cell disease is sometimes necessary. The occurrence of delayed haemolytic transfusion reaction is a rare but potentially serious complication. This event can occur at any age. It is probably under diagnosed due to the difficulty in diagnosis with few specific signs. CASE REPORTS: We describe in this article the clinical, biological, and hazards of therapeutic management of three cases of delayed haemolytic transfusion reaction in sickle cell disease patients. The high performance chromatography, which evaluates the percentage of HbA1, is the biological investigation used to establish the diagnosis of this event. The pathophysiology of this event remains still poorly understood. Several treatments have been used during this event. However, the therapeutic management remains controversial. CONCLUSION: Transfusion in any patient likely to suffer from delayed haemolytic transfusion reaction is not recommended because of the risk of worsening this reaction. Prevention of recurrence is essential.