Successful use of eculizumab for treatment of an acute hemolytic reaction after ABO-incompatible red blood cell transfusion

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.

Adverse transfusion reactions and what we can do

INTRODUCTION

Transfusions of blood and blood components have inherent risks and the ensuing adverse reactions. It is very important to understand the adverse reactions of blood transfusion comprehensively for ensuring the safety of any future transfusions.

AREAS COVERED

According to the time of onset, adverse reactions of blood transfusion are divided into immediate and delayed transfusion reactions. In acute transfusion reactions, timely identification and immediate cessation of transfusion is critical. Vigilance is required to distinguish delayed responses or reactions that present non-specific signs and symptoms. In this review, we present the progress of mechanism, clinical characteristics and management of commonly encountered transfusion reactions.

EXPERT OPINION

The incidence of many transfusion-related adverse events is decreasing, but threats to transfusion safety are always emerging. It is particularly important for clinicians and blood transfusion staff to recognize the causes, symptoms and treatment methods of adverse blood transfusion reactions to improve the safety. In the future, at-risk patients will be better identified and can benefit from more closely matched blood components.

Blood Transfusion Reactions-A Comprehensive Review of the Literature including a Swiss Perspective

Blood transfusions have been the cornerstone of life support since the introduction of the ABO classification in the 20th century. The physiologic goal is to restore adequate tissue oxygenation when the demand exceeds the offer. Although it can be a life-saving therapy, blood transfusions can lead to serious adverse effects, and it is essential that physicians remain up to date with the current literature and are aware of the pathophysiology, initial management and risks of each type of transfusion reaction. We aim to provide a structured overview of the pathophysiology, clinical presentation, diagnostic approach and management of acute transfusion reactions based on the literature available in 2022. The numbers of blood transfusions, transfusion reactions and the reporting rate of transfusion reactions differ between countries in Europe. The most frequent transfusion reactions in 2020 were alloimmunizations, febrile non-hemolytic transfusion reactions and allergic transfusion reactions. Transfusion-related acute lung injury, transfusion-associated circulatory overload and septic transfusion reactions were less frequent. Furthermore, the COVID-19 pandemic has challenged the healthcare system with decreasing blood donations and blood supplies, as well as rising concerns within the medical community but also in patients about blood safety and transfusion reactions in COVID-19 patients. The best way to prevent transfusion reactions is to avoid unnecessary blood transfusions and maintain a transfusion-restrictive strategy. Any symptom occurring within 24 h of a blood transfusion should be considered a transfusion reaction and referred to the hemovigilance reporting system. The initial management of blood transfusion reactions requires early identification, immediate interruption of the transfusion, early consultation of the hematologic and ICU departments and fluid resuscitation.

Severe Acute Hemolytic Transfusion Reaction Treated with Ruxolitinib and Plasma Exchange

Introduction

Acute hemolytic transfusion reaction is a rare but extremely mortal condition. Even small quantities of ABO-incompatible erythrocytes, as much as 50 mL, can lead to fatality. Since there is no successful standard therapy, preventive measures are very important. In this case report, we presented a 29-year-old woman who was transfused with 2 units of AB Rh-positive instead of 0 Rh-positive red blood cells following a cesarean section. As far as we know, this is the first patient in the literature for whom ruxolitinib was used as a part of therapy.

Case Report

The patient was referred to our center 22 h after the ABO-mismatched transfusion. On admission, she had severe hemolysis, acute renal failure, and disseminated intravascular coagulation. Massive plasma exchange, hemodialysis, and pulse steroid therapy were commenced. The patient was refractory to first-line therapies. She was intubated on day 2 due to hypoxia, respiratory failure and changes in consciousness. Ruxolitinib, 2 × 10 mg/day, was started on day 3. The patient's clinical status improved on day 6. Ruxolitinib was withdrawn on day 15, and the patient was discharged without any complications or sequels on day 26.

Conclusion

Ruxolitinib may be life-saving in patients with ABO-incompatible transfusion reaction which follows a severe and catastrophic course.

Hemolysis: Mechanism and clinico-biological consequences

Hemolysis is a clinical entity, which can be severe. It is commonly of multifactorial etiology. The activity of a specialist in transfusion medicine consists in treating the patient with transfusion support in case of severe anemia. If the etiology is partly alloimmune this therapeutic strategy is more arduous. Immunohematological work-up must be very rigorous to ensure transfusion management with utmost safety. However, without the precise knowledge of both the clinical condition and the treatment (current and past) of the patient, such management is impossible.

Delayed Severe Hemolytic Transfusion Reaction During Pregnancy in a Woman with β-Thalassemia Intermediate: Successful Outcome After Eculizumab Administration

BACKGROUND Delayed hemolytic transfusion reactions (DHTR) are life-threatening complications mostly triggered by red blood cell (RBC) transfusions in patients with hemoglobinopathy. CASE REPORT We present a case of DHTR and hyperhemolysis syndrome in a 39-year-old pregnant woman with a history of ß-thalassemia intermediate in whom the hemoglobin (Hb) level fell to 27 g/L after transfusion of 2 units of crossmatch-compatible packed RBCs. No allo- or auto-antibody formation was detected. Administration of intravenous immunoglobulins and methylprednisolone followed by anti-CD20 rituximab was tried, but was unsuccessful. Infusions of eculizumab (900 mg twice at a 7-day interval) followed by another course of intravenous immunoglobulins (2 g/kg/day for 5 days) and combined with repeated erythropoietin injections (darbepoetin alpha 300 µg/week) finally allowed biological and clinical improvement. Blood counts remained controlled until delivery. Despite signs of intrauterine growth retardation, she gave birth by cesarean section at 31 weeks of pregnancy to a 1.15-kg infant. CONCLUSIONS Eculizumab seems to be of benefit in DHTR associated with hyperhemolysis and should be used early in the treatment of this pathology. Despite premature birth, our case report showed an acceptable outcome for the infant when eculizumab treatment was used during pregnancy.

Risk factors for hemolytic transfusion reactions resulting from ABO and minor red cell antigen incompatibility: From mislabeled samples to stem cell transplant and sickle cell disease

Advances in laboratory testing, pathogen reduction and donor qualification have dramatically reduced the risk of acquiring an infection from a blood transfusion. Despite this progress, the most feared complication of transfusion - a hemolytic reaction due to incompatibility between donor and recipient - remains, with essentially no recent progress in the prevention or recognition of this rare but frequently lethal complication. Herein, the role that compatibility testing and transfusion practice play in the occurrence of acute hemolysis are described, with a special emphasis on clinical scenarios confer an increased risk of a severe hemolytic reaction in response to red blood cell or platelet transfusion. In addition, the signs and symptoms of a severe hemolytic reaction are summarized, along with the initial approach to clinical management.

Eculizumab in cold agglutinin disease (DECADE): an open-label, prospective, bicentric, nonrandomized phase 2 trial

Cold agglutinin disease (CAD) is a complement-dependent disorder, with extravascular and intravascular hemolysis resulting from initial or terminal complement activation, respectively. We tested the efficacy and safety of eculizumab, an inhibitor of the terminal complement pathway. Treatment-requiring patients received 600 mg eculizumab weekly for 4 weeks, followed 1 week later by 900 mg every other week through week 26. The primary end point was the difference in the lactate dehydrogenase level between the first and the last day of therapy. Twelve patients with chronic CAD and 1 patient with an acute cold agglutinin syndrome were included. The median lactate dehydrogenase level decreased from 572 U/L (interquartile range [IQR], 534-685) to 334 U/L (IQR, 243-567; P = .0215), paralleled by an increase in hemoglobin from 9.35 g/dL (IQR, 8.80-10.80) to 10.15 g/dL (IQR, 9.00-11.35; P = .0391; Wilcoxon signed-rank test). Three patients maintained and 8 patients acquired transfusion independence, and 1 patient each showed a reduced or increased transfusion requirement, respectively (P = .0215; exact McNemar's test). Patients with cold agglutinins with a thermal amplitude of 37°C tended to have less pronounced lactate dehydrogenase responses than patients with cold agglutinins with narrower thermal amplitudes. In the latter, responses were observed at lower serum levels of eculizumab than they were in the former. In contrast to hemolysis, cold-induced circulatory symptoms remained unaffected. In conclusion, eculizumab significantly reduced hemolysis and transfusion requirement in patients with CAD. Suppression of hemolysis caused by cold agglutinins with a wide thermal amplitude may require higher eculizumab doses than used here. The trial is registered with EudraCT (#2009-016966-97) and www.clinicaltrials.gov (#NCT01303952).

Noninfectious transfusion-associated adverse events and their mitigation strategies

Blood transfusions are life-saving therapies; however, they can result in adverse events that can be infectious or, more commonly, noninfectious. The most common noninfectious reactions include febrile nonhemolytic transfusion reactions, allergic transfusion reactions, transfusion-associated circulatory overload, transfusion-related acute lung injury, and acute and delayed hemolytic transfusion reactions. These reactions can be asymptomatic, mild, or potentially fatal. There are several new methodologies to diagnose, treat, and prevent these reactions. Hemovigilance systems for monitoring transfusion events have been developed and demonstrated decreases in some adverse events, such as hemolytic transfusion reactions. Now vein-to-vein databases are being created to study the interactions of the donor, product, and patient factors in the role of adverse outcomes. This article reviews the definition, pathophysiology, management, and mitigation strategies, including the role of the donor, product, and patient, of the most common noninfectious transfusion-associated adverse events. Prevention strategies, such as leukoreduction, plasma reduction, additive solutions, and patient blood management programs, are actively being used to enhance transfusion safety. Understanding the incidence, pathophysiology, and current management strategies will help to create innovative products and continually hone in on best transfusion practices that suit individualized patient needs.

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.

Complement activation by human red blood cell antibodies: hemolytic potential of antibodies and efficacy of complement inhibitors assessed by a sensitive flow cytometric assay

BACKGROUND

Therapeutic intervention strategies in complement-mediated hemolytic diseases are still inappropriate, and lethal events cannot be reliably prevented. As an in vitro model of intravascular hemolysis, a sensitive flow cytometric assay was designed using red blood cells (RBCs) of patients with paroxysmal nocturnal hemoglobinuria (PNH) as target cells. Complement activation by human allo- and autoantibodies directed against RBC antigens and the effect of different complement inhibitors were studied.

STUDY DESIGN AND METHODS

RBCs of patients with a PNH III RBC clone of more than 20% were coated with different human allo- or autoantibodies. Hemolysis was initiated with pooled normal human AB serum with or without the addition of complement inhibitors. Loss of PNH III RBCs was estimated by flow cytometry.

RESULTS

RBC antibodies of 174 different patients representing 37 different specificities were tested for their potency to activate complement. In correlation with blood group specificities roughly three different patterns were observed: 1) strong and regular, 2) sporadic, and 3) weak or absent complement activation. Remarkably strong complement activators were among antibodies directed against high-prevalence blood group antigens. The C5 inhibitor eculizumab abrogated mild but not strong complement activation, even in presence of excess inhibitor. However, this residual complement activity could be further depressed by combining eculizumab with other inhibitors.

CONCLUSION

The PNH hemolysis assay offers a sensitive tool for in vitro analyses of classical pathway-mediated complement activation. The recognition of additive effects of complement inhibitors may guide novel intervention strategies against unwanted complement damage.

Eculizumab for Prevention of Antibody-Mediated Rejection in Blood Group-Incompatible Renal Transplantation

Antibody-mediated rejection (AMR) is one of the leading causes of allograft failure especially in patients undergoing ABO-incompatible (ABOi) renal transplantation. We hypothesized that complement inhibition with eculizumab, a C5 inhibitor, would protect against AMR and maintain graft function in ABOi renal transplant recipients. Four patients undergoing living donor kidney transplant from ABOi donors were treated with a 9-week eculizumab course without therapeutic plasma exchange, intravenous immunoglobulin, or splenectomy. All patients had successful transplants and have normal graft function at the time of last follow-up. There were no cases of AMR or acute cellular rejection. Of note, 2 patients were transplanted despite persistent ABO antibody titers of 1:32, conventionally considered a contraindication to proceed in standard protocols. Eculizumab is a promising option to prevent AMR with ABOi renal transplantation without the need for splenectomy, post-transplant therapeutic plasma exchange, and intravenous immunoglobulin. Future multicenter studies are needed to determine long-term efficacy and safety.

A case of ABO-incompatible blood transfusion treated by plasma exchange therapy and continuous hemodiafiltration

ABO-incompatible blood transfusion is potentially a life-threatening event. A 74-year-old type O Rh-positive male was accidentally transfused with 280 mL type B Rh-positive red blood cells during open right hemicolectomy, causing ABO-incompatible blood transfusion. Immediately after the transfusion, the patient experienced a hypotension episode followed by acute hemolytic reaction, disseminated intravascular coagulation and acute kidney injury. Plasma exchange therapy was performed to remove anti-B antibody and free hemoglobin because they caused acute hemolytic reaction, disseminated intravascular coagulation, and acute kidney injury. Free hemoglobin levels decreased from 13 to 2 mg/dL for 2 h. Continuous hemodiafiltration was used to stabilize hemodynamics. The patient was successfully treated for acute hemolytic reaction, disseminated intravascular coagulation, and acute kidney injury. Plasma exchange therapy and continuous hemodiafiltration are likely to be effective treatments for ABO-incompatible blood transfusion, and further studies are required to assess this effectiveness in future.

Eculizumab for Thrombotic Microangiopathy Associated with Antibody-Mediated Rejection after ABO-Incompatible Kidney Transplantation

Thrombotic microangiopathy is a form of antibody-mediated rejection (ABMR): it is the main complication of ABO-incompatible (ABOi) kidney transplantation (KT). Herein, we report on two cases of ABMR with biological and histological features of thrombotic microangiopathy (TMA) that were treated by eculizumab after ABOi KT. The first patient presented with features of TMA at postoperative day (POD) 13. Because of worsening biological parameters and no recovery of kidney function, despite seven sessions of immunoadsorption, a salvage therapy of eculizumab was started on POD 23. Kidney function slightly improved during the first 4 months after transplantation. Eculizumab was stopped at month 4. However, kidney function worsened progressively, leading to dialysis at month 13 after transplantation. The second patient presented with features of TMA at POD 1. In addition to immunoadsorption therapy, eculizumab was started on POD 6. Kidney function improved. Eculizumab was stopped on POD 64 and immunoadsorption sessions were stopped on POD 102. At the last follow-up (after 9 months), eGFR was at 43 mL/min/1.73 m². Our case reports show the beneficial effect of eculizumab to treat ABMR after ABOi KT. However, it should be given early after diagnosing TMA associated with ABMR.

Transfusion reactions: prevention, diagnosis, and treatment

Blood transfusion is one of the most common procedures in patients in hospital so it is imperative that clinicians are knowledgeable about appropriate blood product administration, as well as the signs, symptoms, and management of transfusion reactions. In this Review, we, an international panel, provide a synopsis of the pathophysiology, treatment, and management of each diagnostic category of transfusion reaction using evidence-based recommendations whenever available.

The relative merits of therapies being developed to tackle inappropriate ('self'-directed) complement activation

The complement system is an enzyme cascade that helps defend against infection. Many complement proteins occur in serum as inactive enzyme precursors or reside on cell surfaces. Complement components have many biologic functions and their activation can eventually damage the plasma membranes of cells and some bacteria. Although a direct link between complement activation and autoimmune diseases has not been found, there is increasing evidence that complement activation significantly contributes to the pathogenesis of a large number of inflammatory diseases that may have autoimmune linkage. The inhibition of complement may therefore be very important in a variety of autoimmune diseases since their activation may be detrimental to the individual involved. However, a complete and long-term inhibition of complement may have some contra side effects such as increased susceptibility to infection. The site of complement activation will, however, determine the type of inhibitor to be used, its route of application and dosage level. Compared with conventional drugs, complement inhibitors may be the best option for treatment of autoimmune diseases. The review takes a critical look at the relative merits of therapies being developed to tackle inappropriate complement activation that are likely to result in sporadic autoimmune diseases or worsen already existing one. It covers the complement system, general aspects of complement inhibition therapy, therapeutic strategies and examples of complement inhibitors. It concludes by highlighting on the possibility that a better inhibitor of complement activation when found will help provide a formidable treatment for autoimmune diseases as well as preventing one.

Life-threatening delayed hyperhemolytic transfusion reaction in a patient with sickle cell disease: effective treatment with eculizumab followed by rituximab

BACKGROUND

Hyperhemolysis in sickle cell disease is a rare and potentially life-threatening complication of transfusion.

STUDY DESIGN AND METHODS

In this article we report a case of delayed hemolytic transfusion reaction with resultant hyperhemolysis triggered by an anti-IH autoantibody with alloantibody behavior.

RESULTS

The anti-IH was reactive at room temperature as well as 37 °C, but only weakly reactive with autologous red blood cells. Initial cold agglutinin titer was 512. The profound, life-threatening, intravascular hemolysis was rapidly and dramatically reduced with the Complement 5 (C5) inhibitory antibody, eculizumab. The auto/allo cold agglutinin was subsequently suppressed with rituximab treatment.

CONCLUSIONS

Eculizumab, a potent C5 inhibitory antibody, can be a rapid and effective therapy for hyperhemolytic transfusion reactions when given in a sufficient dose to fully block the activation of complement C5.