Pathogenesis, risk factors and therapeutic options for autoimmune haemolytic anaemia in the post‐transplant setting

Abstract

Summary Autoimmune haemolytic anaemia (AIHA) is a rare complication of allogeneic haematopoietic stem cell transplantation (HSCT), observed with an incidence of 1–5%. Paediatric age, diagnosis of non‐malignant disease, lympho‐depleting agents in the conditioning regimen, use of unrelated donor, graft versus host disease and infections have been associated with a higher risk of AIHA post HSCT. Post‐HSCT AIHA is associated with high mortality and morbidity, and it is often very difficult to treat. Steroids and rituximab are used with a response rate around 30–50%. These and other therapeutic strategies are mainly derived from data on primary AIHA, although response rates in post‐HSCT AIHA have been generally lower. Here we review the currently available data on risk factors and therapeutic options. There is a need for prospective studies in post‐HSCT AIHA to guide clinicians in managing these complex patients.

The effect of HLA matching and donor relatedness on the risk of autoimmune haemolytic anaemia in haematopoietic stem cell transplant recipients: A systematic review and meta‐analysis

“…Autoimmune haemolytic anaemia (AIHA) is a condition in which an autoimmune response is mounted against the patient's own red cell antigens, leading to haemolysis [ 1 ]. Recently, AIHA has emerged as a relatively common complication of haematopoietic stem cell transplant (HSCT), with an incidence of approximately 1%–6% depending on the associated population [ 1 , 2 , 3 ].…”

“…Autoimmune haemolytic anaemia (AIHA) is a condition in which an autoimmune response is mounted against the patient's own red cell antigens, leading to haemolysis [ 1 ]. Recently, AIHA has emerged as a relatively common complication of haematopoietic stem cell transplant (HSCT), with an incidence of approximately 1%–6% depending on the associated population [ 1 , 2 , 3 ]. Previous studies have found that this complication is especially prevalent in paediatric populations, and there is limited evidence that it may be impacted by donor and recipient factors such as human leucocyte antigen (HLA) matching and donor source [ 4 , 5 , 6 , 7 , 8 ].…”

“…Furthermore, AIHA can be classified according to the class of autoantibodies that are produced in the patient and its thermal amplitude, including warm AIHA (wAIHA), cold AIHA (cold agglutinin disease [CAD]), mixed AIHA and atypical forms [ 2 ]. Typically, wAIHA, which includes immunoglobulin G (IgG) antibodies that react at 37°C, is the most common, with up to two‐third of patients presenting with this form [ 1 ]. In contrast, cold AIHA generally involves IgM antibodies that react at room temperature and typically account for one‐third of AIHA cases [ 1 ].…”

“…Typically, wAIHA, which includes immunoglobulin G (IgG) antibodies that react at 37°C, is the most common, with up to two‐third of patients presenting with this form [ 1 ]. In contrast, cold AIHA generally involves IgM antibodies that react at room temperature and typically account for one‐third of AIHA cases [ 1 ]. Approximately 5% of patients present with mixed‐type AIHA, which can present with both antibody classes.…”

“…In the post‐allogeneic HSCT transplant setting, autoimmunity refers to donor lymphocytes that target donor‐derived tissue or antigens common between both the donor and recipient [ 6 ]. Autoimmune reactions after HSCT are a relatively common complication, with AIHA having the highest incidence of approximately 1%–6% [ 1 , 2 , 3 ]. Typically, these AIHA cases are wAIHA, frequently with a pan‐reactive antibody, and are often resistant to treatment [ 3 , 6 ].…”