Tocilizumab in the management of posttransfusion hyperhemolysis syndrome in sickle cell disease: The experience so far

An Unusual Case of Hyperhemolysis Syndrome and Delayed Hemolytic Transfusion Reaction due to Anti-Jk(a) and Anti-P1 Antibodies

Background

Hyperhemolysis syndrome (HS) is a severe hemolytic transfusion reaction that can cause hemoglobin and hematocrit levels to drop below pretransfusion levels, leading to severe anemia. HS most commonly occurs in patients with a pre-existing hemoglobinopathy such as sickle cell disease (SCD) or beta-thalassemia.

Methods

We report a case of HS, occurring in the absence of hemoglobinopathy, making the diagnosis challenging. The patient reported was also affected by a CIC-rearranged sarcoma. As part of the workup, the patient received a bone marrow biopsy for suspected hemophagocytic lymphohistiocytosis.

Results

This provided a rare biopsy specimen to correlate reticulocytopenia with marked erythroid hyperplasia in the marrow, supporting the hypothesis of reticulocyte destruction as a contributing cause of anemia in these patients. This patient had demonstrable alloantibodies to the Jk(a) and P1 antigens as potential triggers for HS.

Conclusions

It is vital that a diagnosis of HS be correctly made in these patients with severe anemia, as blood transfusions generally lead to worsening of their conditions.

Alloimmunization and hyperhemolysis in sickle cell disease

Alloimmunization against red blood cell antigens and delayed hemolytic transfusion reaction (DHTR) are major barriers to transfusion in sickle cell disease (SCD). In SCD, DHTR is a potentially life-threatening. Blood group polymorphism in SCD patients, who are of African ancestry and frequently exposed to antigens they do not carry; an inflammatory clinical state; and occasional transfusion in acute situations are risk factors for alloimmunization and DHTR. In patients at risk, the transfusion indication must be balanced against the risk of developing DHTR. However, when transfusion is absolutely necessary, protocols combining the prevention of exposure to immunogenic antigens with immunosuppressive treatments must be implemented, and patients should be carefully monitored during posttransfusion follow-up. This close monitoring makes it possible to diagnose hyperhemolysis as soon as possible; to avoid retransfusion, which can exacerbate hemolysis; and to administer specific treatments, such as anticomplement therapy, in severe cases. Finally, in patients with severe disease, hematopoietic stem cell transplantation may be indicated. However, transfusion is also required in this context, and its management is complex because these risks must be taken into account.

The role of tocilizumab in the treatment of post-transfusion hyperhaemolysis

Hyperhaemolysis syndrome (HHS) is a serious complication of transfusion mostly reported in patients with sickle cell disease. HHS is characterised by the destruction of both donor and autologous red blood cells. Tocilizumab is a recombinant humanised monoclonal antibody that inhibits the binding of interleukin-6 and has been used in the treatment of severe/critical coronavirus disease 2019 infection but also some cases of HHS. We describe two further cases of HHS successfully treated with tocilizumab and propose a decision aid for when to consider this treatment.

Alloimmunisation against red blood cells in sickle cell disease: transfusion challenges in high-income and low-income countries

Sickle cell disease is the most frequent inherited disorder in sub-Saharan Africa and in many high-income countries (HICs). Transfusion is a key element of treatment, but it results in high rates of alloimmunisation against red blood cell antigens and post-transfusion haemolysis, which can be life-threatening in severe cases. The prevention of alloimmunisation is, therefore, an important issue in both HICs and in low-income countries (LICs). In HICs, the main reason for high alloimmunisation rates is blood group disparity between blood donors, who are mostly of European descent, and the patients, who are mostly of African descent. However, alloimmunisation rates also remain high in sub-Saharan Africa despite the homogeneity of blood group antigen frequencies between donors and patients; this occurrence is probably due to matching strategies limited to ABO blood group and RhD. However, other possible underlying causes of alloimmunisation have also been suggested, with each cause affecting HICs and LICs in different ways-eg, the immunogenetic and inflammatory status of the patient and the characteristics of the red blood cell products. In this Viewpoint, we discuss the available data and hypotheses that potentially account for the association of sickle cell disease with high rates of alloimmunisation in both settings, HICs and LICs (focusing particularly on sub-Saharan Africa), and the challenges faced by HICs and LICs to improve prevention of alloimmunisation.

Adverse events of red blood cell transfusions in patients with sickle cell disease

Blood transfusion is a common medical intervention for patients with sickle cell disease (SCD) and disease related complications. While patients with SCD are at risk for all transfusion related adverse events defined by the National Healthcare Safety Network (NHSN) Biovigilance Component Hemovigilance Module Surveillance Protocol, they are uniquely susceptible to certain adverse events. This review discusses risk factors, mitigation strategies, and management recommendations for alloimmunization, hemolytic transfusion reactions, hyperviscosity and transfusion-associated iron overload in the context of SCD.

Acute Hyperhemolysis Syndrome in a Patient with Known Sickle Cell Anemia Refractory to Steroids and IVIG Treated with Tocilizumab and Erythropoietin: A Case Report and Review of Literature

Patients with sickle cell anemia often receive multiple red blood cell (RBC) transfusions during their lifetime. Hyperhemolysis is a life-threatening phenomenon of accelerated hemolysis and worsening anemia that occurs when both transfused RBCs and autologous RBCs are destroyed. The level of hemoglobin post-transfusion is lower than pre-transfusion levels, and patients are usually hemodynamically unstable. Hyperhemolysis must be differentiated from a delayed hemolytic transfusion reaction during which destruction of transfused RBC is the cause of anemia. Hyperhemolysis syndrome can be differentiated into acute (within seven days) and chronic forms (after seven days) post-transfusion. The authors present a case of acute hyperhemolysis syndrome in a patient with sickle cell anemia refractory to steroids and IVIG, which are the treatment of choice. The patient was treated with tocilizumab, combined with supportive measures of erythropoietin, iron, vitamin B12, and folate.

Hyperhemolysis in a patient with sickle cell disease and recent SARS-COV-2 infection, with complex auto- and allo-antibody work-up, successfully treated with tocilizumab

BACKGROUND

Hyperhemolysis syndrome (HHS) is a severe delayed hemolytic transfusion reaction seen in sickle cell disease (SCD) patients, characterized by destruction of donor and recipient RBCs. It results in a drop in hemoglobin to below pretransfusion levels and frequently reticulocytopenia.

CASE REPORT

We report a case of a man in his 30s with SCD with a recent hospitalization two weeks prior for COVID-19. His red cell antibody history included anti-Fy(a) and warm autoantibody. At that time he was given two units of pRBC and discharged with a hemoglobin of 10.2 g/dL. He returned to the hospital approximately 1.5 weeks later with hemoglobin 6.0 g/dL and symptoms concerning for acute chest syndrome (ACS). Pretransfusion testing now showed 4+ pan-agglutinin in both gel-based and tube-based testing. Alloadsorption identified an anti-N and a strong cold agglutinin. Three least incompatible units were transfused to this patient over several days, with evidence of hemolysis. Further reference lab work revealed anti-Fy^a , anti-Fy^b , anti-Le^a , anti-Le^b , and an anti-KN system antibody. The patient's hemoglobin nadired at 4.4 g/dL. The patient was treated with a single dose of tocilizumab, his hemoglobin stabilized, and he was discharged.

DISCUSSION

We present a case of HHS proximate to recent SARS-CoV-2 infection with multiple allo and autoantibodies identified. Information on the relationship between SARS-CoV-2 infection and HHS is limited, however, it is possible that inflammation related to COVID-19 could predispose to HHS. Tocilizumab is an approved treatment for COVID-19. Additionally, tocilizumab appears to be a promising treatment option for patients with HHS.