Autoimmune hemolytic anemia in solid organ transplantation-The role of immunosuppression

Blood group genotype matching for transfusion

The last decade has seen significant growth in the application of DNA-based methods for extended antigen typing, and the use of gene sequencing to consider variation in blood group genes to guide clinical care. The challenge for the field now lies in educating professionals, expanding accessibility and standardizing the use of genotyping for routine patient care. Here we discuss applications of genotyping when transfusion is not straightforward including when compatibility cannot be demonstrated by routine methods, when Rh type is unclear, when allo- and auto-antibodies are encountered in stem cell and organ transplantation, for prenatal testing to determine maternal and foetal risk for complications, and Group A subtyping for kidney and platelet donors. We summarize current commercial testing resources and new approaches to testing including high-density arrays and targeted next-generation sequencing (NGS).

The Role of the Spleen and the Place of Splenectomy in Autoimmune Hemolytic Anemia-A Review of Current Knowledge

Autoimmune hemolytic anemia (AIHA) is a rare, very heterogeneous, and sometimes life-threatening acquired hematologic disease characterized by increased red blood cell (RBC) destruction by autoantibodies (autoAbs), either with or without complement involvement. Recent studies have shown that the involvement of T- and B-cell dysregulation and an imbalance of T-helper 2 (Th2) and Th17 phenotypes play major roles in the pathogenesis of AIHA. AIHA can be primary (idiopathic) but is more often secondary, triggered by infections or drug use or as a part of other diseases. As the location of origin of autoAbs and the location of autoAb-mediated RBC clearance, as well as the location of extramedullary hematopoiesis, the spleen is crucially involved in all the steps of AIHA pathobiology. Splenectomy, which was the established second-line therapeutic option in corticosteroid-resistant AIHA patients for decades, has become less common due to increasing knowledge of immunopathogenesis and the introduction of targeted therapy. This article provides a comprehensive overview of current knowledge regarding the place of the spleen in the immunological background of AIHA and the rapidly growing spectrum of novel therapeutic approaches. Furthermore, this review emphasizes the still-existing expediency of laparoscopic splenectomy with appropriate perioperative thromboprophylaxis and the prevention of infection as a safe and reliable therapeutic option in the context of the limited availability of rituximab and other novel therapies.

The Link between Iron Turnover and Pharmacotherapy in Transplant Patients

Iron is a transition metal that plays a crucial role in several physiological processes. It can also exhibit toxic effects on cells, due to its role in the formation of free radicals. Iron deficiency and anemia, as well as iron overload, are the result of impaired iron metabolism, in which a number of proteins, such as hepcidin, hemojuvelin and transferrin, take part. Iron deficiency is common in individuals with renal and cardiac transplants, while iron overload is more common in patients with hepatic transplantation. The current knowledge about iron metabolism in lung graft recipients and donors is limited. The problem is even more complex when we consider the fact that iron metabolism may be also driven by certain drugs used by graft recipients and donors. In this work, we overview the available literature reports on iron turnover in the human body, with particular emphasis on transplant patients, and we also attempt to assess the drugs’ impact on iron metabolism, which may be useful in perioperative treatment in transplantology.

Successful Treatment of Autoimmune Hemolytic Anemia Concomitant with Proliferation of Epstein-Barr Virus in a Post-Heart Transplant Patient

Autoimmune hemolytic anemia (AIHA) is a rare complication following heart transplantation and has been attributed to several etiologies including infections, immunosuppressive medications, and post-transplant lymphoproliferative disorders. We report a 23-year-old male presenting 22 years after heart transplantation with severe AIHA. Laboratory findings were notable for positive IgG autoantibody against RBCs and high titer Epstein-Barr virus (EBV) viremia. Shortly after the first unit of irradiated RBC transfusion and high dose steroids, the patient developed acute dyspnea and hypoxia requiring intubation. Further workup demonstrated that the patient had Methicillin-sensitive Staphylococcus aureus (MSSA) pneumonia (PNA) and bacteremia, requiring antibiotics. Patient was subsequently treated with high-dose steroids, IVIG, as well as rituximab. Following treatment, the patient was successfully extubated and eventually showed complete resolution of the anemia. This case is novel as it represents AIHA likely secondary to EBV viremia in a post-cardiac transplant patient complicated by a severe transfusion reaction. In this circumstance, rituximab in conjunction with standard of care remains an effective treatment of choice.

Autoimmune diseases after allogeneic stem cell transplantation: a clinician's guide and future outlook

INTRODUCTION

Autoimmune disease (AD) may occur after allogeneic hematopoietic stem cell transplantation (HSCT). The autoimmune mechanism seems to be related to an imbalance of the immune regulation effect of T-regulatory lymphocytes on autoreactive T-lymphocytes.

AREAS COVERED

ADs include hematological ADs (HADs) and nonhematologic ADs (NHADs) involving organs such as thyroid, peripheral and central nervous system, skin, liver, connective tissue, gastrointestinal tract, and kidney. To identify the risk factors for ADs, to report their clinical characteristics, and to discuss new approaches represent the areas covered in this review.

EXPERT OPINION

Some risk factors for HAD and NHAD are common and include nonmalignant diseases, young age, cord blood as a stem cell source, conditioning regimens without total body irradiation, alemtuzumab, antithymocyte globulin, T-cell-depleted transplant, some viral infection, mixed chimerism, and chronic Graft versus Host Disease. In NHADs, the detection of autoantibodies is more frequent and the transfer of autoimmunity from the donor to the recipient represents the pathogenetic mechanism responsible for these complications. New therapeutic approaches such as bortezomib, daratumumab, sirolimus, eculizumab, and eltrombopag appear to be promising in terms of better efficacy and reduced toxicity compared to traditional therapies. New horizons based on personalized therapies will allow us to improve the prognosis of AD.

Autoimmune Hemolytic Anemia in the Pediatric Setting

Autoimmune hemolytic anemia (AIHA) is a rare disease in children, presenting with variable severity. Most commonly, warm-reactive IgG antibodies bind erythrocytes at 37 °C and induce opsonization and phagocytosis mainly by the splenic macrophages, causing warm AIHA (w-AIHA). Post-infectious cold-reactive antibodies can also lead to hemolysis following the patient’s exposure to cold temperatures, causing cold agglutinin syndrome (CAS) due to IgM autoantibodies, or paroxysmal cold hemoglobinuria (PCH) due to atypical IgG autoantibodies which bind their target RBC antigen and fix complement at 4 °C. Cold-reactive antibodies mainly induce intravascular hemolysis after complement activation. Direct antiglobulin test (DAT) is the gold standard for AIHA diagnosis; however, DAT negative results are seen in up to 11% of warm AIHA, highlighting the need to pursue further evaluation in cases with a phenotype compatible with immune-mediated hemolytic anemia despite negative DAT. Prompt supportive care, initiation of treatment with steroids for w-AIHA, and transfusion if necessary for symptomatic or fast-evolving anemia is crucial for a positive outcome. w-AIHA in children is often secondary to underlying immune dysregulation syndromes and thus, screening for such disorders is recommended at presentation, before initiating treatment with immunosuppressants, to determine prognosis and optimize long-term management potentially with novel targeted medications.

New Insights in Autoimmune Hemolytic Anemia: From Pathogenesis to Therapy Stage 1

Autoimmune hemolytic anemia (AIHA) is a highly heterogeneous disease due to increased destruction of autologous erythrocytes by autoantibodies with or without complement involvement. Other pathogenic mechanisms include hyper-activation of cellular immune effectors, cytokine dysregulation, and ineffective marrow compensation. AIHAs may be primary or associated with lymphoproliferative and autoimmune diseases, infections, immunodeficiencies, solid tumors, transplants, and drugs. The direct antiglobulin test is the cornerstone of diagnosis, allowing the distinction into warm forms (wAIHA), cold agglutinin disease (CAD), and other more rare forms. The immunologic mechanisms responsible for erythrocyte destruction in the various AIHAs are different and therefore therapy is quite dissimilar. In wAIHA, steroids represent first line therapy, followed by rituximab and splenectomy. Conventional immunosuppressive drugs (azathioprine, cyclophosphamide, cyclosporine) are now considered the third line. In CAD, steroids are useful only at high/unacceptable doses and splenectomy is uneffective. Rituximab is advised in first line therapy, followed by rituximab plus bendamustine and bortezomib. Several new drugs are under development including B-cell directed therapies (ibrutinib, venetoclax, parsaclisib) and inhibitors of complement (sutimlimab, pegcetacoplan), spleen tyrosine kinases (fostamatinib), or neonatal Fc receptor. Here, a comprehensive review of the main clinical characteristics, diagnosis, and pathogenic mechanisms of AIHA are provided, along with classic and new therapeutic approaches.

Autoimmunity Following Allogeneic Hematopoietic Stem Cell Transplantation

Autoimmune manifestations after allogeneic hematopoietic stem cell transplantation (AHSCT) are rare and poorly understood due to the complex interplay between the reconstituting immune system and transplant-associated factors. While autoimmune manifestations following AHSCT have been observed in children with graft-versus-host disease (GvHD), an alloimmune process, they are distinct from the latter in that they are generally restricted to the hematopoietic compartment, i.e., autoimmune hemolytic anemia, thrombocytopenia, and/or neutropenia. Autoimmune cytopenias in the setting of ASHCT represent a donor against donor immune reaction. Non-hematologic autoimmune conditions in the post-AHSCT setting have been described and do not currently fall under the GvHD diagnostic criteria, but could represent alloimmunity since they arise from the donor immune attack on the antigens that are shared by the donor and host in the thyroid, peripheral and central nervous systems, integument, liver, and kidney. As in the non-transplant setting, autoimmune conditions are primarily antibody mediated. In this article we review the incidence, risk factors, potential pathophysiology, treatment, and prognosis of hematologic and non-hematologic autoimmune manifestations in children after AHSCT.

Bortezomib for autoimmune hemolytic anemia after intestinal transplantation

AIHA is rare in the general population and associated with a mortality of 8%. In contrast, AIHA occurs in up to 12.2% of cases after intestinal transplantation and is associated with mortality up to 50%. Treatment entails a "step-up" approach including corticosteroids, IvIg, plasmapheresis, and rituximab. However, AIHA after transplantation often is refractory to this strategy, contributing to a poor outcome. We describe a child with microvillous inclusion disease who developed AIHA 1 year after multivisceral transplantation that was refractory to standard therapy and was subsequently treated with bortezomib.We observed remission of AIHA within 1 week after the start of bortezomib. Bortezomib was associated with transient diarrhea, leucopenia, and elevated liver enzymes. Three years later, he remains in remission without important complications. Published data on bortezomib for autoimmune cytopenias outside SOT are discussed. This is the first report to support bortezomib as an important therapeutic alternative for AIHA after SOT. The occurrence and treatment of AIHA after SOT, and specifically intestinal transplantation, should be the subject of future registry studies to collect additional experience and explore the optimal therapeutic approach.

Protective Effects of Nargenicin A1 against Tacrolimus-Induced Oxidative Stress in Hirame Natural Embryo Cells

Tacrolimus is widely used as an immunosuppressant to reduce the risk of rejection after organ transplantation, but its cytotoxicity is problematic. Nargenicin A1 is an antibiotic extracted from Nocardia argentinensis and is known to have antioxidant activity, though its mode of action is unknown. The present study was undertaken to evaluate the protective effects of nargenicin A1 on DNA damage and apoptosis induced by tacrolimus in hirame natural embryo (HINAE) cells. We found that reduced HINAE cell survival by tacrolimus was due to the induction of DNA damage and apoptosis, both of which were prevented by co-treating nargenicin A1 or N-acetyl-l-cysteine, a reactive oxygen species (ROS) scavenger, with tacrolimus. In addition, apoptosis induction by tacrolimus was accompanied by increases in ROS generation and decreases in adenosine triphosphate (ATP) levels caused by mitochondrial dysfunction, and these changes were significantly attenuated in the presence of nargenicin A1, which further indicated tacrolimus-induced apoptosis involved an oxidative stress-associated mechanism. Furthermore, nargenicin A1 suppressed tacrolimus-induced B-cell lymphoma-2 (Bcl-2) down-regulation, Bax up-regulation, and caspase-3 activation. Collectively, these results demonstrate that nargenicin A1 protects HINAE cells against tacrolimus-induced DNA damage and apoptosis, at least in part, by scavenging ROS and thus suppressing the mitochondrial-dependent apoptotic pathway.

Autoimmune hemolytic anemia: An unusual presentation of hemophagocytic lymphohistiocytosis in a pediatric post-liver transplant patient

Hemophagocytic lymphohistiocytosis (HLH), a rare condition characterized by immune dysfunction with uncontrolled activation of macrophages and hypersecretion of cytokines, has only been reported in a small number of pediatric patients following solid organ transplant (SOT). The diagnosis of HLH after SOT is especially difficult, as several of the diagnostic criteria, including fever, splenomegaly, and cytopenias, are nonspecific and can be seen with other post-transplant complications. Autoimmune hemolytic anemia (AIHA) has also been reported after pediatric SOT and is thought to be related to immunosuppression, specifically tacrolimus. Although HLH and AIHA have been separately described following SOT, there have been no reports of them occurring together in post-liver transplant (LT) patients. We report the first case of autoimmune hemolysis as the presenting symptom of HLH in a pediatric post-LT patient.