Warm antibody autoimmune hemolytic anemia

Overall Survival and Treatment Patterns Among Patients With Warm Autoimmune Hemolytic Anemia in Sweden: A Nationwide Population-based Study

OBJECTIVES

Warm autoimmune hemolytic anemia (wAIHA) is a rare autoantibody-mediated disorder, and first-line treatment primarily relies on corticosteroids. This study assessed overall survival (OS) and treatment patterns of wAIHA in Sweden.

METHODS

Adults with ≥ 1 primary diagnosis code for wAIHA (or AIHA plus oral corticosteroids (OCS)/immunosuppressants as sensitivity analyses) between 2011 and 2022 were identified from five Swedish national registers and linked through each patient's unique identity number. Kaplan-Meier curves with log-rank tests and Cox regressions were performed to assess OS for patients with primary versus secondary wAIHA and patients with wAIHA and long-term versus short-term (≥ 3 vs. < 3 months) OCS users.

RESULTS

The main analysis included 292 patients; 1791 patients were included in the sensitivity analysis. At a median 3.7-year follow-up, a median OS in primary wAIHA was not reached versus 6.0 years for secondary wAIHA (log-rank test: p = 0.003). Subgroup analyses showed no significant difference in risk of death between long-term and short-term OCS users; however, in the sensitivity analysis, long-term OCS users showed significantly higher risk of death (adjusted hazard ratio: 1.45; 95% confidence interval: 1.180, 1.781; p < 0.001) versus short-term OCS users.

CONCLUSION

Secondary wAIHA or long-term OCS use was associated with lower OS, underscoring the disease burden and unmet need for efficacious wAIHA treatments.

Severe, Refractory Primary Warm Autoimmune Hemolytic Anemia Requiring 90 Erythrocyte Transfusions

A previously healthy 60-year-old man presented to the hospital with a hemoglobin of 3.5 g/dL. He was diagnosed with severe warm autoimmune hemolytic anemia (wAIHA) with reticulocytopenia on hospital day 1 that was not responsive to steroids, immune globulin, and rituximab. Over a 42-day hospital stay, the patient remained continuously transfusion-dependent with a ninety red cell unit requirement for his refractory disease. He was trialed on therapeutic plasma exchange before ultimately undergoing inpatient splenectomy that led to a response within hours. He remains in complete remission at six months of follow-up.

Pediatric autoimmune hemolytic anemia: A single-center retrospective study

BACKGROUND

Autoimmune hemolytic anemia (AIHA) is a rare, life-threatening disease in pediatrics. This article describes the clinical features, diagnostic workup, treatment and outcome in patients with AIHA.

METHOD

Medical charts of under 18-year-old patients with AIHA treated at a tertiary Brazilian institution from 2006 to 2021 were retrospectively reviewed. Data analysis was primarily descriptive, using medians, interquartile ranges, and categorical variables presented as absolute frequencies.

MAIN RESULTS

Twenty-four patients (14 female, 10 male) were evaluated in this study. The median age at diagnosis was 5.99 years (range: 0.25-17.1 years) and the median hemoglobin level was 4.85 g/dL (range: 4.17-5.57 g/dL). Most had warm antibodies (83.3 %). Twelve patients (50 %) had known underlining diseases, four (16.6 %) presented with AIHA concomitant with acute infectious diseases and three (12.5 %) had an undetermined post-vaccine association. Steroids and intravenous immunoglobulin were first-line therapy in 23 cases. Seven patients (29.1 %) required second and third-line treatments (rituximab, cyclophosphamide and splenectomy). The median follow-up period was 4.4 years (range: 1.0-6.7 years). Thirteen patients (54.1 %) were discharged, five cases (20.8 %) were lost to follow-up and no patient died. The median age for the six remaining patients was 11.53 years (8.5-14.7) with all of them having complete responses with no further therapies.

CONCLUSION

Most cases of AIHA are secondary to an underlying systemic disease or have a possible correlation with infections/vaccines and respond to steroids. The second and third-line therapies for refractory and relapse cases remain a dilemma. A prospective, multicenter study is essential to address the best therapeutic combinations.

Les cytopénies auto-immunes de l’enfant : Quand penser au déficit immunitaire primitif ?

Autoimmune cytopenias are defined by autoantibodies' immune destruction of one or more blood elements. Most often it is autoimmune hemolytic anemia or immune thrombocytopenia or both that define Evans syndrome. It may be secondary to infection or to underlying pathology such as systemic autoimmune disease or primary immunodeficiency, especially when it becomes chronic over several years. Primary Immunodeficiencies or inborn errors of immunity (IEI) are no longer defined solely by infections: autoimmunity is part of the clinical features of several of these diseases. It is dominated by autoimmune cytopenias, in particular, immune thrombocytopenia (ITP) and autoimmune hemolytic anaemia (AIHA). The challenges for the clinician are the situations where autoimmune cytopenias are chronic, recurrent and/or refractory to the various long-term therapeutic options. Most of these therapies are similar in action and generally consist of non-mediated immune suppression or modulation. In these situations, primary Immunodeficiencies must be diagnosed as soon as possible to allow the initiation of a targeted treatment and to avoid several ineffective therapeutic lines.

Autoimmune Hemolytic Anemia Associated With Myelodysplastic Syndrome: A Case Report

Myelodysplastic syndrome (MDS) represents a spectrum of myeloid disorders occasionally linked to autoimmune diseases. Here, we present a case of a 60-year-old man demonstrating an unusual coexistence of MDS with warm-autoantibody autoimmune hemolytic anemia (wAIHA). Diagnostic evaluation, including positive direct antiglobulin testing, confirmed the autoimmune etiology of his anemia despite his low-risk MDS classification. Prompt initiation of prednisone therapy resulted in significant hematological and clinical improvement, allowing for a conservative management approach without transfusion requirements. This case underscores the importance of identifying the relationship between wAIHA and MDS, particularly in low-risk scenarios. Moreover, these findings suggest the efficacy of corticosteroids in managing autoimmune anemia in the context of concomitant wAIHA and MDS.

Warm Autoimmune Hemolytic Anemia Secondary to Babesia Microti Infection: A Case Report

Babesia microti is a parasite endemic to the northeastern and midwestern regions of the United States of America and a leading cause of babesiosis. Babesiosis has a non-specific presentation, which can delay diagnosis, leading to increased morbidity and mortality. As the number of reported babesiosis cases increases, there is a need to create more awareness of some atypical presentations that allow for early recognition and treatment. This case report identifies a 75-year-old male with intact spleen who presented with warm autoimmune hemolytic anemia secondary to B. microti and had complete recovery within less than a month after treatment was initiated. We also briefly report on the known and suspected pathophysiology and treatment courses.

Warm autoimmune hemolytic anemia: new insights and hypotheses

PURPOSE OF REVIEW

Warm autoimmune hemolytic anemia (wAIHA) is the most common of the immune hemolytic anemias. Although there are numerous case reports and reviews regarding this condition, some of the unusual and more recent findings have not been fully defined and may be contentious. This review will provide insight into the common specificity of the warm autoantibodies and hypothesize a novel mechanism of wAIHA, that is proposed to be linked to the controversial subject of red blood cell senescence.

RECENT FINDINGS AND HYPOTHESES

It is now well established that band 3 on the red blood cell is the main target of autoantibodies in wAIHA. wAIHA targets the older red blood cells (RBCs) in about 80% of cases and, recently, it has been shown that the RBCs in these patients are aging faster than normal. It has been proposed that in these 80% of patients, that the autoantibody recognizes the senescent red blood cell antigen on band 3. It is further hypothesized that this autoantibody's production and potency has been exacerbated by hypersensitization to the RBC senescent antigen, which is processed through the adaptive immune system to create the pathogenic autoantibody. Recent publications have supported previous data that the senescent RBC antigen is exposed via a dynamic process, wherein oscillation of a band 3 internal loop flipping to the cell surface, creates a conformational neoantigen that is the RBC senescent antigen. It has also recently been shown that the cytokine profile in patients with wAIHA favors production of inflammatory cytokines/chemokines that includes interleukin-8 which can activate neutrophils to increase the oxidative stress on circulating RBCs to induce novel antigens, as has been postulated to favour exposure of the senescent RBC antigen.

SUMMARY

This manuscript reviews new findings and hypotheses regarding wAIHA and proposes a novel mechanism active in most wAIHA patients that is due to an exacerbation of normal RBC senescence.

Case report: Autoimmune hemolytic anemia caused by warm and cold autoantibodies with complement activation-etiological and therapeutic issues

Introduction

Research on mixed warm and cold autoantibodies in autoimmune hemolytic anemia (AIHA) targeting erythrocytes [red blood cells (RBCs)] and platelets is scarcely reported.

Case presentation

In this study, we present the case of a 5-year-old boy with positive direct [anti-IgG (1+), anti-IgG-C3d (3+)], and indirect antiglobulin (Coombs) tests. The RBCs were coated with polyspecific-positive, warm IgG autoantibodies alongside activated complement components. Plasma-containing immunoglobulin M (IgM) class autoantibodies were found in 1:64 titers with a wide temperature range of 4°C-37°C. The platelets were also coated with IgM autoantibodies. There was a reduction in the levels of the classical and alternative complement pathways, such as C3, C4, ADAMTS13 metalloprotease activity, factor H antigen, complement factor B antigen, and C1q antigen alongside the elevated sC5b-9 terminal complement complex. Hematuria and/or proteinuria, reduced diuresis, and elevated levels of serum creatinine were absent. The kidney ultrasound report was normal. A recent combination of Epstein-Barr virus (EBV) and cytomegalovirus (CMV) infection was found. The first-line treatment consisted of intravenous methylprednisolone [4 mg/kg/body weight for the first 72 h (q12 h), followed by 2 mg/kg body weight for 21 consecutive days with a slow steroid reduction until plasmapheresis (PLEX)]. After the patient showed limited response to corticosteroid therapy, rituximab (375 mg/m2) was administered once a week (five doses in total), with vitamins B9 and B12. These strategies also showed limited (partial) therapeutic benefits. Therefore, the treatment was switched to PLEX (five cycles in total) and intravenous immunoglobulin (IVIg) (1 g/kg/5 days). This combination significantly improved RBC count and platelet levels, and C3 and C4 levels returned to normal. A follow-up of 2.5 years after treatment showed no sign of relapse. A genetic analysis revealed a rare heterozygous intronic variation (c.600-14C > T) and heterozygous Y402H polymorphism of the CFH gene. c.600-14C > T mutation was located near the 5' end of exon 6 in the gene encoding the complement C3 protein of unknown significance. We presumed that the complement regulators in our patient were sufficient to control complement activation and that complement blockade should be reserved only for devastating, life-threatening complement-related multiorgan failure.

Conclusion

We believe that EBV and CMV triggered AIHA, thus activating the complement cascade. Hence, we used corticosteroids, rituximab, vitamins B9 + B12, PLEX, and fresh frozen plasma (FFP) as treatment. Final remission was achieved with PLEX and FFP. However, an additional late effect of B12 rituximab and the disappearance of long-lived circulating plasma cells should not be completely ignored. Complement activation with a genetic background should be assessed in severe warm and cold hemolytic anemias caused by autoantibodies.

Metaxalone-induced Immune Hemolytic Anemia

Drug-induced immune hemolytic anemia (DIIHA) is a relatively uncommon cause of anemia, and its diagnosis can be challenging. Although beta-lactam antimicrobial agents are often associated with DIIHA, any medication can potentially cause it. We describe a patient presenting with yellow skin discoloration and orange-colored urine after starting metaxalone for treatment of lumbosacral sprain. Laboratory studies were consistent with warm hemolytic anemia. Symptoms improved remarkably after discontinuation of metaxalone, coupled with initiation of glucocorticoids and rituximab.

An Adjusted Process to Improve Efficiency and Efficacy of Adsorption Procedures to Resolve Warm Autoantibody Cases

OBJECTIVE

The presence of warm autoantibodies in patient plasma 
typically causes extended delays in patient care due to panreactive antibody identification tests. Adsorption is the primary method for resolution. A modified adsorption procedure was devised with the intent to minimize delays, and the aim of the study was to evaluate its efficacy.

METHODS

To evaluate the in-house developed (experimental) adsorption method, specimens were tested in parallel with the standard adsorption method described in the AABB Technical Manual, 20th edition. Specimens selected demonstrated panreactivity at the submitting facility and contained adequate volume for parallel adsorption studies.

RESULTS

Ninety specimens were tested with both methods. Ninety specimens achieved complete adsorption with the experimental method and 88 specimens achieved complete adsorption with the standard method. Two underlying alloantibodies, which have been reported to cause hemolytic transfusion reactions and potential renal graft rejection, were detected using the experimental method that the standard method failed to detect.

CONCLUSION

The experimental method demonstrated a significant reduction in rounds of adsorption required to resolve warm autoantibody reactivity, enhanced antibody detection ability with adsorbed plasma, and more cost-effective outcomes compared to the standard method. A follow-up study is planned to assess whether the incubation time can be decreased with the experimental method to further improve the efficiency of the method without sacrificing efficacy.

Autoimmune Hemolytic Anemia in the Pediatric Age Group: The Egyptian Experience

Autoimmune hemolytic anemia (AIHA) is a common disease entity among adults; however, it is rare among the pediatric age group. Evidence is scarce regarding pediatric AIHA in the literature. The objective of this study is to assess the frequency of AIHA and describe the clinical and laboratory characteristics and treatment outcomes of a cohort of children with AIHA in Egypt. A retrospective study was conducted on 50 children with AIHA who were registered and followed up at the New Children's Hospital in Cairo, Egypt, between January 2010 and January 2021. The study group comprised 60% females and 40% males. Their median age was 8.25 years. All patients showed low hemoglobin levels with a mean of 5.40 ± 1.34 g/dl and a median reticulocyte count of 10 (IQR: 8-15). Twelve (24%) patients were diagnosed with Evans syndrome, and a positive Coombs test was detected in 46 patients (92%). The frequency of primary AIHA was 40%, whereas it was 60% for secondary AIHA. The first line of therapy for acute attacks was high-dose IV steroids which responded well in 38 (76%) patients. Secondary AIHA was more common among our children (60%). AIHA is more prevalent in females (60%). The clinical and laboratory characteristics matched previous reports.

Autoimmune Hemolytic Anemia Following Uncomplicated Spinal Surgery: A Report and Brief Review

This report and literature review describes a case of a Coombs test-positive warm antibody autoimmune hemolytic anemia (AIHA) in a patient following routine spinal surgery without complications. This is the first reported case of symptomatic direct Coombs test-positive warm antibody AIHA developing in a neurosurgical patient. The patient is a 73-year-old female with left radicular leg pain who developed warm antibody AIHA following standard uncomplicated spinal surgery. A positive direct Coombs test confirmed the diagnosis in combination with characteristic laboratory values. The patient did not have any significant predisposing risk factors. On postoperative day (POD) 23, she presented with fatigue and characteristic laboratory values of decreased hemoglobin, elevated bilirubin, lactate dehydrogenase, and decreased haptoglobin. Hematology initiated and monitored appropriate treatment and proposed that the working hematologic diagnosis is stress-induced AIHA secondary to recent spinal surgery. The patient recovered well from a neurosurgical perspective and reported no neurosurgical complaints during the last follow-up. A female presenting with left radicular leg pain developed symptomatic anemia following uncomplicated spinal surgery. A positive direct Coombs test in combination with characteristic laboratory values confirmed the diagnosis of warm antibody AIHA.

Lymphoplasmacytic Lymphoma/Waldenstrom Macroglobulinemia Masquerading as IgM Warm Antibody Autoimmune Hemolytic Anemia in Association With Mycoplasma pneumoniae Infection: A Case Report

Warm antibody autoimmune hemolytic anemia (AIHA) is mostly of IgG subtype. IgM subtype is extremely rare and has not been reported in association with lymphoplasmacytic lymphoma (LPL)/Waldenström macroglobulinemia (WM). We are reporting the case of a 75-year-old female patient who presented with severe hemolytic anemia and Mycoplasma pneumoniae pneumonia (MPP). Cold agglutinin and serum protein electrophoresis (SPEP) were negative but immunofixation was positive for IgM. Ultimately, hemolytic anemia was labeled warm antibody AIHA in association with MPP. She presented again one year later with more severe hemolytic anemia. Persistently elevated IgM was seen in immunofixation and triggered bone marrow biopsy that confirmed LPL/WM. This case highlights the clinical pearl that warm antibody AIHA in association with MPP is a rare entity and more intensive investigation to rule out other etiologies is mandated. Also, this case is rare as it is of IgM subtype warm AIHA and observed in the context of LPL/WM.

Autoantibodies in immunodeficiency syndromes: The Janus faces of immune dysregulation

Immunodeficiency syndromes represent a diverse group of inherited and acquired disorders, characterized by a spectrum of clinical manifestations, including recurrent infections, autoimmunity, lymphoproliferation and malignancy. Autoantibodies against various self-antigens reflect the immune dysregulation underlying these disorders, and could contribute to certain clinical findings, such as susceptibility to opportunistic infections, cytopenia of different hematopoietic lineages, and organ-specific autoimmune diseases. The mechanism of autoantibody production in the context of immunodeficiency remains largely unknown but is likely shaped by both intrinsic genetic aberrations and extrinsic exposures to possible infectious agents. These autoantibodies if harbor neutralizing activities and reach certain levels in the circulation, could disrupt the biological functions of their targets, resulting in specific clinical manifestations. Herein, we reviewed the prevalence of autoantibodies against cytokines, hematopoietic cells and organ-specific antigens in immunodeficiency syndromes and examined their associations with certain clinical findings. Moreover, the potential mechanism of autoantibody production was also discussed. These may shed light on the development of mechanism-based therapies to reset the dysregulated immune system in immunodeficient patients.

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.

Anemia in the pediatric patient

The World Health Organization estimates that approximately a quarter of the world's population suffers from anemia, including almost half of preschool-age children. Globally, iron deficiency anemia is the most common cause of anemia. Other important causes of anemia in children are hemoglobinopathies, infection, and other chronic diseases. Anemia is associated with increased morbidity, including neurologic complications, increased risk of low birth weight, infection, and heart failure, as well as increased mortality. When approaching a child with anemia, detailed historical information, particularly diet, environmental exposures, and family history, often yield important clues to the diagnosis. Dysmorphic features on physical examination may indicate syndromic causes of anemia. Diagnostic testing involves a stepwise approach utilizing various laboratory techniques. The increasing availability of genetic testing is providing new mechanistic insights into inherited anemias and allowing diagnosis in many previously undiagnosed cases. Population-based approaches are being taken to address nutritional anemias. Novel pharmacologic agents and advances in gene therapy-based therapeutics have the potential to ameliorate anemia-associated disease and provide treatment strategies even in the most difficult and complex cases.

Haematological Drugs Affecting Lipid Metabolism and Vascular Health

Many drugs affect lipid metabolism and have side effects which promote atherosclerosis. The prevalence of cancer-therapy-related cardiovascular (CV) disease is increasing due to development of new drugs and improved survival of patients: cardio-oncology is a new field of interest and research. Moreover, drugs used in transplanted patients frequently have metabolic implications. Increasingly, internists, lipidologists, and angiologists are being consulted by haematologists for side effects on metabolism (especially lipid metabolism) and arterial circulation caused by drugs used in haematology. The purpose of this article is to review the main drugs used in haematology with side effects on lipid metabolism and atherosclerosis, detailing their mechanisms of action and suggesting the most effective therapies.

Methodologies and tools to shed light on erythrophagocytosis

Red blood cells (RBC) are the most abundant circulating cell of the human body. RBC are constantly exposed to multiple stresses in the circulation, leading to molecular and structural impairments and death. The physiological process of RBC senescence or ageing is referred to as eryptosis. At the end of their lifespan, aged RBC are recognized and removed from the blood by professional phagocytes via a phenomenon called erythrophagocytosis (EP); the phagocytosis of RBC. Some genetic and acquired diseases can influence eryptosis, thereby affecting RBC lifespan and leading to hemolytic anemia. In some diseases, such as diabetes and atherosclerosis, eryptosis and EP can participate in disease progression with both professional and non-professional phagocytes. Therefore, investigating the process of EP in vivo and in vitro, as well as in different cell types, will not only contribute to the understanding of the physiological steps of EP, but also to the deciphering of the specific mechanisms involving RBC and EP that underlie certain pathologies. In this review, the process of EP is introduced and the different methods for studying EP are discussed together with examples of the experimental procedures and materials required.

Direct antibody test negative autoimmune hemolytic anemia with pulmonary tuberculosis: A diagnostic challenge

Tuberculosis (TB) has varied manifestations, but autoimmune hemolytic anemia (AIHA) due to TB is rare. Direct antibody test (DAT) or Coombs negative AIHA is also rare. We report a case of a 14-year-old boy who presented with hemolytic anemia and pneumonia. The Coombs test was repeatedly negative. After ruling out the possible infectious and noninfectious causes by extensive investigations, he was diagnosed as DAT-negative AIHA by monospecific antibody test with 4°C low ionic strength saline washes and column agglutination method which revealed the presence of IgG-2+ antibodies. Bronchoalveolar lavage fluid for acid-fast bacilli and gene Xpert was also positive. It is important to recognize TB as a cause of AIHA in South Asian countries where its incidence is high.

Is Rituximab-Associated Hypogammaglobulinemia Always Linked to B-Cell Depletion?

We describe a case of a 3-year-old male toddler with a history of severe and refractory warm antibody autoimmune hemolytic anemia (w-AIHA) since early infancy and hypogammaglobulinemia persisting 20 months after rituximab administration (second-line rescue therapy). Specifically, although peripheral blood flow cytometry B-cell population counts signified B-cell recovery following completion of rituximab therapy, IgG levels were barely detectable. Detailed laboratory evaluation did not reveal any humoral or cell-mediated immunity impairment and the patient remained asymptomatic, without any infections or recurrence of w-AIHA. Due to severe hypogammaglobulinemia, he was placed on immunoglobulin replacement therapy (IVIG). The implemented PID (primary immunodeficiency) gene panel identified only variants of uncertain significance (VUS). The aim of this report is to underline the documentation of persisting hypogammaglobulinemia after rituximab despite peripheral blood B-cell reconstitution.

Type O blood, the MCHC, and the reticulocyte count impact the early recurrence of primary warm-antibody autoimmune hemolytic anemia in children: A retrospective cohort analysis

OBJECTIVE

Primary warm-antibody autoimmune hemolytic anemia (w-AIHA) is prone to recurrence in children. In this study, we aimed to identify risk indicators for the early recurrence of primary w-AIHA and construct an effective recurrence risk assessment model.

METHODS

This was a retrospective cohort study. The clinical data of patients hospitalized with primary w-AIHA in the Department of Hematology and Oncology, Children's Hospital of Chongqing Medical University, between 1 January 2018 and 30 September 2021, were collected at the initial diagnosis. Univariate and multivariate logistic regression analyses were used to determine risk indicators for the early recurrence of primary w-AIHA in children, and ROC curve and Kaplan-Meier survival analyses were used for verification. Finally, a risk assessment model for early recurrence in children with primary w-AIHA was constructed using Cox regression and visualized using a nomogram. The model was also verified internally and externally.

RESULTS

This study included 62 children with primary w-AIHA. Of which, 18 experienced recurrence 1 year after the initial diagnosis. The univariate and multivariate logistic regression analyses showed that type O blood and the reticulocyte count (Ret) were risk indicators for the early recurrence of pediatric primary w-AIHA (P = 0.009, 0.047, respectively). The mean corpuscular hemoglobin concentration (MCHC) is a protective factor (P = 0.040). According to the ROC curve and Kaplan-Meier survival analyses, children with primary w-AIHA whose blood type was O or had an MCHC of <313.5 pg/fL or a Ret of ≥0.161×10¹²/L had a higher risk of early recurrence (HR = 2.640, 4.430 and 4.450, respectively, and P = 0.040, 0.015 and 0.018, respectively). The blood types (O), MCHCs, and Rets of 56 patients were incorporated into the Cox regression model, and the recurrence risk assessment model for children with primary w-AIHA was successfully constructed and visualized using a nomogram. The calibration curves and decision-curve analysis (DCA) suggested that the risk model has clinical applicability and effectiveness.

CONCLUSION

Children with type O blood and an MCHC value of <313.5 pg/fL or a Ret value of ≥0.161×10¹²/L have a higher risk of early recurrence. The risk assessment model for the early recurrence of pediatric primary w-AIHA constructed in this study has good clinical applicability and effectiveness.

Diagnosis and clinical management of red cell membrane disorders

Heterogeneous red blood cell (RBC) membrane disorders and hydration defects often present with the common clinical findings of hemolytic anemia, but they may require substantially different management, based on their pathophysiology. An accurate and timely diagnosis is essential to avoid inappropriate interventions and prevent complications. Advances in genetic testing availability within the last decade, combined with extensive foundational knowledge on RBC membrane structure and function, now facilitate the correct diagnosis in patients with a variety of hereditary hemolytic anemias (HHAs). Studies in patient cohorts with well-defined genetic diagnoses have revealed complications such as iron overload in hereditary xerocytosis, which is amenable to monitoring, prevention, and treatment, and demonstrated that splenectomy is not always an effective or safe treatment for any patient with HHA. However, a multitude of variants of unknown clinical significance have been discovered by genetic evaluation, requiring interpretation by thorough phenotypic assessment in clinical and/or research laboratories. Here we discuss genotype-phenotype correlations and corresponding clinical management in patients with RBC membranopathies and propose an algorithm for the laboratory workup of patients presenting with symptoms and signs of hemolytic anemia, with a clinical case that exemplifies such a workup.

Autoimmune Hemolytic Anemia Exacerbation Associated With COVID-19 Infection and Markedly Elevated Inflammatory Markers

The association between previously diagnosed autoimmune hemolytic anemia and exacerbations due to coronavirus disease 2019 (COVID-19) infection is a rare phenomenon that is not well understood. In this case, we present a 68-year-old female with a past medical history significant for systemic lupus erythematosus (SLE), splenectomy, and autoimmune hemolytic anemia (AIHA) since childhood that had been very well controlled with only one previous exacerbation. This patient's chief complaint and clinical symptoms at admission were related to hemolytic anemia and not active COVID-19 infection. This case report reveals a possible association between the hyperinflammatory syndrome caused by COVID-19 and the exacerbation of previously well-controlled autoimmune diseases.

Anti-plasma cell treatment in refractory autoimmune hemolytic anemia in a child with multivisceral transplant

BACKGROUND

Warm-antibody AIHA is known to complicate solid organ (SOT) and HSCT, the disease maybe refractory to standard therapy. Immunosuppressive therapies as well as IVIG, and rituximab have been the main stay of treatment. Over the past decade, B-lymphocyte targeted, anti-CD-20 antibody has been recognized in the treatment of autoimmune diseases and utilized in AIHA. Bortezomib, a proteasome inhibitor that causes apoptosis of plasma cells, is an appealing targeted therapy in secondary AIHA and has demonstrated efficacy in HSCT patients. From our experience, we advocate for early targeted therapy that combines B cell with plasma cell depletion.

CASE REPORT

We describe a 4-year-old-girl with stage III neuroblastoma, complicated with intestinal necrosis needing multivisceral transplant developed warm AIHA 1-year after transplantation, and following an adenovirus infection. She received immunoglobulin therapy, rituximab, sirolimus, plasmapheresis, and long-term prednisolone with no sustained benefit while developing spinal fractures related to the latter therapy. She received bortezomib for intractable AIHA in combination with rituximab with no appreciable adverse effects. Three years later the child remains in remission with normal reticulocyte and recovered B cells. In the interim, she required chelation therapy for iron overload related to blood transfusion requirement during the treatment of AIHA.

CONCLUSION

We propose early targeted anti-plasma cell therapy with steroid burst, IVIG, rituximab, and possible plasmapheresis may reduce morbidity in secondary refractory w-AIHA.

COVID-19-Associated Severe Autoimmune Hemolytic Anemia: A Rare Case Report

Autoimmune hemolytic anemia (AIHA) is a very rare presentation of COVID-19, and AIHA due to COVID-19 alone (i.e., in the absence of an associated underlying disorder) is extremely rare. Warm agglutinin disease accounts for the majority of AIHA in general. Here, we report a case of a 23-year-old male with bronchial asthma who was referred to our hospital with SARS-COV-2 infection and severe anemia presenting as acute immune-mediated hemolytic crisis due to warm autoimmune hemolytic anemia (AIHA). Extensive laboratory testing was performed, including polyspecific direct antiglobulin test, complete autoimmune workup and common infections leading to AIHA were ruled out by serology and molecular methods. The patient required multiple blood transfusions and other therapeutic interventions before clinical stabilization. Treatment of new-onset AIHA is always challenging in the presence of an active viral replication; combining immunosuppression with active COVID-19 infection creates extremely difficult diagnostic and management settings, as this case illustrates.

Warm Autoimmune Hemolytic Anemia Associated With Asymptomatic SARS-CoV-2 Infection

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the resultant coronavirus disease 2019 (COVID-19) are associated with several hematologic abnormalities, including immune thrombocytopenia, antiphospholipid syndrome, and autoimmune hemolytic anemia (AIHA). Initial case reports suggested immune dysregulation to be the underlying etiology of SARS-CoV-2-associated AIHA, as all reported cases involved patients with moderate to severe COVID-19, many of whom had underlying lymphoproliferative disorders. More recently, AIHA has been reported in patients with mildly symptomatic SARS-CoV-2 infection. Here, we detail a patient with asymptomatic SARS-CoV-2 infection who presented with severe, symptomatic anemia. Workup was consistent with warm autoimmune hemolytic anemia (WAIHA) secondary to SARS-CoV-2 infection.

Epidemiology of Secondary Warm Autoimmune Haemolytic Anaemia-A Systematic Review and Meta-Analysis

Background: Warm autoimmune haemolytic anaemia (wAIHA) is a haemolytic disorder, most commonly seen among adults and is classified as either primary or secondary to an underlying disease. We describe the age and sex distribution and the proportion of secondary wAIHA. Method: We retrieved 2635 published articles, screened abstracts and titles, and identified 27 articles eligible for full-text review. From these studies, we extracted data regarding number of patients, sex distribution, age at diagnosis, number of patients with secondary wAIHA, and whether the patients were diagnosed through local or referral centres. All data were weighted according to the number of included patients in each study. Results: 27 studies including a total of 4311 patients with wAIHA, of which 66% were females, were included. The median age at diagnosis was 68.7 years, however, wAIHA affected all ages. The mean proportion of secondary wAIHA was 49%, most frequently secondary to systemic lupus erythematosus. The proportions of secondary wAIHA reported from primary vs. referral centres were 35% vs. 59%, respectively. Conclusion: This review consolidates previously reported gender distribution. The higher proportion of secondary wAIHA in referral centres suggests that the most severely affected patients are disproportionally more frequent in such facilities.

How I treat warm autoimmune hemolytic anemia

Warm autoimmune hemolytic anemia (wAIHA) is caused by increased erythrocyte destruction by immunoglobulin G (IgG) autoantibodies, with or without complement activation. Antibody-dependent cell-mediated cytotoxicity by macrophages/activated lymphocytes occurs in the lymphoid organs and spleen (extravascular hemolysis). The ability of the bone marrow (BM) to compensate determines clinical severity. The different pathogenic mechanisms, their complex interplay, and changes over time may explain wAIHA's great clinical heterogeneity and unpredictable course. The disease may be primary, drug induced, or associated with lymphoproliferative neoplasms, autoimmune and infectious diseases, immunodeficiencies, solid tumors, or transplants. Therapeutic interventions include steroids, splenectomy, immunosuppressants, and rituximab; the latter is increasingly used in steroid-refractory cases based on evidence from the literature and a few prospective trials. We present 5 patient case studies highlighting important issues: (1) the diagnosis and proper use of steroid therapy, (2) the concerns about the choice between rituximab and splenectomy in second-line treatment, (3) the need of periodical re-evaluation of the disease to assess the possible evolution of relapsed/refractory cases in myelodysplastic and BM failure syndromes, and (4) the difficulties in managing cases of severe/acute disease that are at high risk of relapse. Incorporating novel targeted therapies into clinical practice will be an exciting challenge in the future.

Autoimmune Hemolytic Anemia and Pulmonary Embolism: An Association to Consider

Autoimmune hemolytic anemia (AIHA) is increasingly recognized as a strong risk factor for venous thrombosis. However, there are currently no guidelines on thromboembolism prevention and management during AIHA. Here, we describe the case of a patient with AIHA and pulmonary embolism and resume the current knowledge on epidemiology, risk factors, treatment, and pathophysiology of thrombosis during AIHA, as well as new therapeutic perspectives to prevent thrombus formation during AIHA.

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.

The Role of mTOR Inhibitors in Hematologic Disease: From Bench to Bedside

The mTOR pathway plays a central role in many cellular processes, such as cellular growth, protein synthesis, glucose, and lipid metabolism. Aberrant regulation of mTOR is a hallmark of many cancers, including hematological malignancies. mTOR inhibitors, such as Rapamycin and Rapamycin analogs (Rapalogs), have become a promising class of agents to treat malignant blood diseases-either alone or in combination with other treatment regimens. This review highlights experimental evidence underlying the molecular mechanisms of mTOR inhibitors and summarizes their evolving role in the treatment of hematologic disease, including leukemia, lymphoma, myeloma, immune hemocytopenia, and graft-versus-host disease (GVHD). Based on data presented in this review, we believe that mTOR inhibitors are becoming a trusted therapeutic in the clinical hematologist's toolbelt and should be considered more routinely in combination therapy for the management of hematologic disease.

Autoantigen presentation by splenic dendritic cells is required for RBC-specific autoimmunity

BACKGROUND

Failure of humoral tolerance to red blood cell (RBC) antigens may lead to autoimmune hemolytic anemia (AIHA), a severe and sometimes fatal disease. Previous studies have shown that although tolerance is robust in HOD mice, autoantibodies are generated upon adoptive transfer of OTII CD4+ T cells, which are specific for an epitope contained within the HOD antigen. These data imply that antigen-presenting cells (APCs) are presenting RBC-derived autoantigen(s) and are capable of driving T-cell activation. Given that multiple APCs participate in erythrophagocytosis, we used a transgenic approach to determine which cellular subsets were required for autoantigen presentation and subsequent autoreactive T-cell activation.

STUDY DESIGN AND METHODS

HOD mice, which express an RBC-specific antigen consisting of hen egg lysozyme, ovalbumin, and human blood group molecule Duffy, were bred with IAbfl/fl and Cre-expressing transgenic animals to generate mice that lack I-Ab expression on particular cell subsets. OTII CD4+ T cell proliferation was assessed in vivo in HOD+ I-Abfl/fl xCre+ mice and in vitro upon coculture with sorted APCs.

RESULTS

Analysis of HOD+ I-Abfl/fl xCre+ mice demonstrated that splenic conventional dendritic cells (DCs), but not macrophages or monocytes, were required for autoantigen presentation to OTII CD4+ T cells. Subsequent in vitro coculture experiments revealed that both CD8+ and CD8- DC subsets participate in erythrophagocytosis, present RBC-derived autoantigen and stimulate autoreactive T-cell proliferation.

CONCLUSION

These data suggest that if erythrocyte T-cell tolerance fails, DCs are capable of initiating autoimmune responses. As such, targeting DCs may be a fruitful strategy for AIHA therapies.

Rituximab Use in Warm and Cold Autoimmune Hemolytic Anemia

Autoimmune hemolytic anemia is a rare condition characterized by destruction of red blood cells with and without involvement of complement. It is associated with significant morbidity and mortality. In warm autoimmune hemolytic anemia, less than 50% of patients remain in long-term remission following initial steroid therapy and subsequent therapies are required. Cold agglutinin disease is a clonal hematologic disorder that requires therapy in the majority of patients and responds poorly to steroids and alkylators. Rituximab has a favorable toxicity profile and has demonstrated efficacy in autoimmune hemolytic anemia in first-line as well as relapsed settings. Rituximab is the preferred therapy for steroid refractory warm autoimmune hemolytic anemia (wAIHA) and as part of the first- and second-line treatment of cold agglutinin disease. This article reviews the mechanism of action of rituximab and the current literature on its role in the management of primary and secondary warm autoimmune hemolytic anemia and cold agglutinin disease.

How I approach hereditary hemolytic anemia and splenectomy

Hereditary hemolytic anemias (HHA) are a heterogeneous group of anemias associated with decreased red cell survival. While there can be clinical benefit of splenectomy in many cases, splenectomy is not appropriate for all types of HHA. Additionally, there are significant risks during and following splenectomy including surgical risks, postsplenectomy sepsis, and thrombotic complications. This review discusses the diagnostic approach to HHA as well as the role of splenectomy in the management. Surgical approaches and outcomes for total and partial splenectomy are discussed.

RNA sequencing of whole blood in dogs with primary immune-mediated hemolytic anemia (IMHA) reveals novel insights into disease pathogenesis

Immune-mediated hemolytic anemia (IMHA) is a life-threatening autoimmune disorder characterized by a self-mediated attack on circulating red blood cells. The disease occurs naturally in both dogs and humans, but is significantly more prevalent in dogs. Because of its shared features across species, dogs offer a naturally occurring model for studying IMHA in people. In this study, we used RNA sequencing of whole blood from treatment-naïve dogs to study transcriptome-wide changes in gene expression in newly diagnosed animals compared to healthy controls. We found many overexpressed genes in pathways related to neutrophil function, coagulation, and hematopoiesis. In particular, the most highly overexpressed gene in cases was a phospholipase scramblase, which mediates the externalization of phosphatidylserine from the inner to the outer leaflet of cell membranes. This family of genes has been shown to be critically important for programmed cell death of erythrocytes as well as the initiation of the clotting cascade. Unexpectedly, we found marked underexpression of many genes related to lymphocyte function. We also identified groups of genes that are highly associated with the inflammatory response and red blood cell regeneration in affected dogs. We did not find any genes that distinguished dogs that lived vs. those that died at 30 days following diagnosis, nor did we find any relevant genomic signatures of microbial organisms in the blood of affected animals. Future studies are warranted to validate these findings and assess their implication in developing novel therapeutic approaches for dogs and humans with IMHA.

Sepsis-induced Autoimmune Hemolytic Anemia: A Case Report

Introduction: Sepsis commonly brings patients to the emergency department (ED). Patient outcomes can vary widely. In some cases, rare complications of sepsis such as autoimmune hemolytic anemia can occur. Case Report: A 68-year-old female presented with sepsis secondary to infected nephrolithiasis. The patient had signs and symptoms consistent with hemolysis upon arrival to the ED. Her hemolysis progressively worsened over a two-day period leading to a diagnosis of warm autoimmune hemolytic anemia. She responded well to treatment; however, her condition began to worsen due to a new infection caused by perforated colonic diverticula. The patient ultimately expired from complications of her perforated colonic diverticula. Conclusion: It is crucial that emergency physicians understand the risk factors, symptoms, pathophysiology, and treatment of this rare complication of sepsis so that favorable patient outcomes can be achieved.

Cold Agglutinin Disease

Cold agglutinin disease (CAD) is an uncommon form of cold autoimmune hemolytic anemia (AIHA). It should be considered in the differential diagnosis of elderly patients with unexplained chronic anemia presenting with or without cold-induced symptoms in the extremities, such as the fingers, ears, and nose. CAD is a complement-mediated process which leads to intravascular and extravascular hemolysis. A stepwise approach to laboratory testing can help confirm the diagnosis. Nearly all cold agglutinins are positive for the C3d direct antiglobulin test (DAT). A negative C3d DAT should prompt investigation of a possible warm AIHA. Ninety percent of cold agglutinins are of the IgM immunoglobulin class and should have a titer of 1:64 or higher at 4°C. Distinction from a warm AIHA is important, as therapy differs for the two entities. Corticosteroids are not effective at treating CAD and should not be used as therapy in these patients. Approximately 45–60% of patients with CAD respond to rituximab monotherapy. Combination therapy of rituximab and fludarabine has been shown to be effective in up to 76% of patients; however, patients experience more mild side effects with this treatment. New anti-complement drugs, such as eculizumab and sutimlimab, are currently in phase-3 trials to determine their efficacy and safety in patients with CAD.

Tolerization of recent thymic emigrants is required to prevent RBC-specific autoimmunity

Autoimmune hemolytic anemia (AIHA) leads to accelerated destruction of autologous red blood cells (RBCs) by autoantibodies. AIHA is a severe and sometimes fatal disease. While there are several therapeutic strategies available, there are currently no licensed treatments for AIHA and few therapeutics result in treatment-free durable remission. The etiology of primary AIHA is unknown; however, secondary AIHA occurs concurrently with lymphoproliferative disorders and infections. Additionally, AIHA is the second most common manifestation of primary immunodeficiency disorders and has been described as a side effect of checkpoint inhibitor therapy. Given the severity of AIHA and the lack of treatment options, understanding the initiation of autoimmunity is imperative. Herein, we utilized a well-described model of RBC biology to dissect how RBC-specific autoreactive T cells become educated against RBC autoantigens. We show that, unlike most autoantigens, T cells do not encounter RBC autoantigens in the thymus. Instead, when they leave the thymus as recent thymic emigrants (RTEs), they retain the ability to positively respond to RBC autoantigens; only after several weeks in circulation do RTEs become nonresponsive. Together, these data suggest that any disruption in this process would lead to breakdown of tolerance and initiation of autoimmunity. Thus, RTEs and this developmental process are potential targets to prevent and treat AIHA.

Autoimmune Hemolytic Anemia in Chronic Myeloid Leukemia

Background

Autoimmune hemolytic anemia (AIHA) might be associated with underlying hematological malignancies such as chronic lymphocytic leukemia. However, the association between AIHA and chronic myelogenous leukemia is extremely unusual.

Summary

We reviewed case reports and series of 54 patients with chronic myeloid leukemia (CML) who developed autoimmune hemolysis between 1952 and 2018. Almost all the patients were in the chronic phase and were classified into transplant and non-transplant groups. The onset of autoimmune hemolysis was earlier in the transplant group and required second- and third-line therapy to control it. The etiology of hemolysis is poorly understood but attributed in the transplant group to immune reconstitution, viral infections, or CML relapse. On the other hand, it is thought to be related in the non-transplant group to CML medications, especially interferon.

Key Messages

Although AIHA is uncommon in chronic myelogenous leukemia patients, it should be in the differential diagnosis list for those who develop a sudden drop in hemoglobin without a bleeding source.

Autoimmune haemolytic anaemias: A retrospective study of 93 patients

INTRODUCTION

Autoimmune haemolytic anaemia (AIHA) is an infrequent and heterogeneous disease in its pathophysiology and clinical behaviour, therefore it is generally managed empirically.

PATIENTS AND METHODS

We conducted an observational, retrospective and multicentre study of 93 patients diagnosed with AHAI in 9 Spanish hospitals between 1987 and 2017, with a median follow-up of 28 months.

RESULTS

Median age of 67 years; 85% AHAI for hot antibodies and 64% primary AHAI. The lowest haemoglobin values at diagnosis related to patients under 45 years of age and serological type IgG+C. Of the patients, 92% received first line treatment, 54% second line, and 27% third line. The warm AHAI were treated in first line with steroids, with overall responses of 83% and complete of 58%. Rituximab in monotherapy or in association with steroids was administered to 34 patients with overall responses close to 100% (complete responses 40-60%), relegating splenectomy to the third line. The immunosuppressive treatment was administered in patients with autoimmune diseases or in corticoid-dependent patients.

DISCUSSION

We found high rates of response to steroids, with very prolonged treatments that cause side effects and corticoid dependence in a third of patients. The combination of steroids with rituximab in the first line, could be indicated in patients with low levels of haemoglobin and serological type IgG+C. The high relapse rates make necessary the development of randomised studies with new drugs or the combination with existing ones, which allow longer response times and with fewer side effects.