Management of Hyperhemolysis in β-thalassemia With Multiple Immunosuppressives, Including Complement Blockade

What is the role of complement in bystander hemolysis? Old concept, new insights

INTRODUCTION

Bystander hemolysis occurs when antigen-negative red blood cells (RBCs) are lysed by the complement system. Many clinical entities including passenger lymphocyte syndrome, hyperhemolysis following blood transfusion, and paroxysmal nocturnal hemoglobinuria are complicated by bystander hemolysis.

AREAS COVERED

The review provides data about the role of the complement system in the pathogenesis of bystander hemolysis. Moreover, future perspectives on the understanding and management of this syndrome are described.

EXPERT OPINION

Complement system can be activated via classical, alternative, and lectin pathways. Classical pathway activation is mediated by antigen-antibody (autoantibodies and alloantibodies against autologous RBCs, infectious agents) complexes. Alternative pathway initiation is triggered by heme, RBC microvesicles, and endothelial injury that is a result of intravascular hemolysis. Thus, C5b is formed, binds with C6-C9 compomers, and MAC (C5b-9) is formulated in bystander RBCs membranes, leading to cell lysis. Intravascular hemolysis, results in activation of the alternative pathway, establishing a vicious cycle between complement activation and bystander hemolysis. C5 inhibitors have been used effectively in patients with hyperhemolysis syndrome and other entities characterized by bystander hemolysis.

Case report: Successful treatment with plasma exchange in life-threatening hyperhemolytic syndrome unrelated to sickle cell disease

INTRODUCTION

Hyperhemolytic syndrome (HHS) is a severe form of delayed transfusion reaction primarily described in sickle cell anemia patients which is characterized by a hemoglobin decrease to pre-transfusion levels or lower, often with reticulocytopenia and no evidence of auto- or allo-antibodies.

CASE PRESENTATION

We present two cases of severe HHS in patients without sickle cell anemia refractory to treatment with steroids, immunoglobulins, and rituximab. In one case, temporary relief was achieved with eculizumab. In both cases, plasma exchange resulted in a profound and immediate response allowing for splenectomy and resolution of hemolysis.

DISCUSSION/CONCLUSION

We discuss the pathophysiology of HHS, its presentation and treatment and expand on the possible role of plasma exchange in this setting.

Hyperhaemolytic transfusion reaction in two β-thalassaemia major patients: The role of eculizumab

WHAT IS KNOWN AND OBJECTIVE

Hyperhaemolytic transfusion reactions are rare life-threatening events predominantly affecting patients with haemoglobinopathies. We report two cases in β-thalassaemia major patients on chronic transfusion therapy and highlight the role of eculizumab in its management.

CASE SUMMARY

Patient 1 presented with intravascular haemolysis on day 7 (D7) post-transfusion and responded to treatment with corticosteroids and intravenous immunoglobulin. However, patient 2 presented with severe symptomatic anaemia (D4 post-transfusion) unresponsive to the aforementioned measures. Eculizumab administration led to resolution of the hyperhaemolysis.

WHAT IS NEW AND CONCLUSION

We report the successful management of hyperhaemolysis with eculizumab in a β-thalassemia major patient.