Autoimmune hemolytic anemia

Autoimmune hemolytic anemia
Name	Autoimmune hemolytic anemia
Field	Hematology, Immunology
Symptoms	Fatigue, pallor, jaundice, dark urine, splenomegaly
Complications	Thrombosis, infection, cardiac failure
Onset	Variable
Causes	Autoantibodies against erythrocytes
Diagnosis	Direct antiglobulin test, hemoglobin, reticulocyte count
Treatment	Corticosteroids, immunosuppression, splenectomy, transfusion

Autoimmune hemolytic anemia is a disorder in which the immune system produces antibodies that bind to and promote destruction of red blood cells, leading to hemolysis and anemia. It intersects clinical hematology, immunology, and transfusion medicine and can be secondary to infections, malignancies, or drugs. Management often requires immunosuppression, supportive transfusion, and coordination with specialists in surgery and infectious disease.

Introduction

Autoimmune hemolytic anemia (AIHA) was characterized through contributions from clinicians and pathologists associated with institutions such as Johns Hopkins Hospital, Mayo Clinic, Massachusetts General Hospital, Memorial Sloan Kettering Cancer Center, and researchers at National Institutes of Health. Historical descriptions parallel advances in serology seen in laboratories like Truman Medical Center and research centers including Imperial College London and Karolinska Institutet. Epidemiologic studies from centers in Oxford, Cambridge, Toronto, Berlin, and Paris have informed prevalence estimates and associations with conditions treated at hospitals such as Mount Sinai Hospital and Cleveland Clinic.

Pathophysiology

Pathophysiology of AIHA involves antibody-mediated opsonization and complement activation with involvement of immune components studied at institutions such as Rockefeller University, Salk Institute, Cold Spring Harbor Laboratory, Pasteur Institute, and Wellcome Trust centers. Mechanisms include IgG binding that promotes Fc receptor–mediated phagocytosis in organs like the spleen—clinical correlations elucidated by investigators at University of Pennsylvania, UCLA, and Stanford University Medical Center. Cold-reactive antibodies with complement fixation have been characterized in studies from McGill University and University College London. Genetic and molecular contributors have been explored by consortia linked to Broad Institute, European Molecular Biology Laboratory, Harvard Medical School, and Johns Hopkins Bloomberg School of Public Health.

Classification and Types

AIHA is classified into warm, cold, mixed, and drug-induced types, categories refined in guidelines from professional bodies including American Society of Hematology, European Hematology Association, British Society for Haematology, World Health Organization, and specialty groups at American College of Physicians. Warm AIHA, often IgG-mediated, is frequently idiopathic or associated with lymphoproliferative disorders seen at centers like MD Anderson Cancer Center and Dana-Farber Cancer Institute. Cold agglutinin disease links to infections cataloged by Centers for Disease Control and Prevention and post-infectious syndromes reported from Cambridge University Hospitals and Royal Free Hospital. Drug-induced forms have been traced to agents evaluated by regulatory agencies such as the Food and Drug Administration and European Medicines Agency.

Clinical Presentation and Diagnosis

Patients present with fatigue, pallor, jaundice, and splenomegaly; acute severe hemolysis can precipitate from infections or treatments used at institutions like Guy's and St Thomas' NHS Foundation Trust and John Radcliffe Hospital. Diagnostic workflow includes hemoglobin measurement, reticulocyte count, lactate dehydrogenase, bilirubin, and the direct antiglobulin test (DAT), with diagnostic standards developed by committees at International Society on Thrombosis and Haemostasis, American Association of Blood Banks, and laboratory groups affiliated with Australian Red Cross Lifeblood. Imaging for splenic size and evaluation for underlying causes often involves cross-specialty teams at University College Hospital, Addenbrooke's Hospital, and tertiary centers like Royal Brompton Hospital.

Treatment and Management

Initial management commonly uses corticosteroids, rituximab, and second-line agents including azathioprine, cyclophosphamide, mycophenolate mofetil, and splenectomy—therapeutic strategies studied in trials conducted at Mayo Clinic, MD Anderson Cancer Center, Vanderbilt University Medical Center, and King's College Hospital. Transfusion support requires coordination with blood services such as American Red Cross, NHS Blood and Transplant, and transfusion medicine experts at UCSF Medical Center due to alloimmunization risk. Novel agents and trials from research centers like Genentech, Novartis, University of Tokyo, and Seoul National University Hospital investigate complement inhibitors, Bruton tyrosine kinase inhibitors, and other targeted therapies.

Prognosis and Complications

Prognosis varies: warm AIHA may respond to therapy with relapse risk monitored in long-term cohorts followed at Mayo Clinic, Royal Marsden Hospital, Scripps Clinic, and academic registries coordinated by European Hematology Association. Complications include thromboembolic events, infections from immunosuppression, and organ dysfunction, outcomes tracked in registries at Swedish National Board of Health and Welfare, Danish National Patient Registry, and multicenter studies organized by European LeukemiaNet. Multidisciplinary care models involving specialists from Beth Israel Deaconess Medical Center, Cleveland Clinic Foundation, and university hospitals in Barcelona, Rome, and Zurich optimize long-term management.

Category:Autoimmune diseases Category:Blood disorders