From the Guidelines
AIHA in hematology stands for Autoimmune Hemolytic Anemia, a condition where the body's immune system mistakenly produces antibodies that attack and destroy its own red blood cells, leading to hemolysis and resulting anemia. This condition can be classified as warm AIHA or cold AIHA, depending on the temperature at which the antibodies are most active. The diagnosis of AIHA typically involves a complete blood count, reticulocyte count, direct Coombs test, and peripheral blood smear examination.
Key Points
- The underlying mechanism involves autoantibodies binding to red blood cell surface antigens, marking them for premature destruction by macrophages primarily in the spleen 1.
- Treatment depends on the type and severity of AIHA, but often includes corticosteroids like prednisone as first-line therapy for warm AIHA 1.
- Other treatments may include immunosuppressants such as rituximab, splenectomy, or transfusions in severe cases 1.
- Symptoms of AIHA include weakness, paleness, jaundice, dark-colored urine, fever, inability to do physical activity, and heart murmur 1.
Diagnosis and Treatment
The diagnosis of AIHA relies on a combination of clinical and laboratory findings, including a complete blood count, reticulocyte count, and direct Coombs test. Treatment should be individualized based on the severity of the disease and the patient's response to therapy. Corticosteroids like prednisone are often used as first-line therapy for warm AIHA, with a typical dose of 1-2 mg/kg/day. In cases where corticosteroids are not effective, other treatments such as immunosuppressants or splenectomy may be considered 1.
From the Research
Definition of AIHA
- Autoimmune hemolytic anemia (AIHA) is an autoimmune disorder in which autoantibodies are directed against an individual's own red blood cells (RBCs), leading to enhanced clearance through Fc receptor (FcR)-mediated phagocytosis 2
- AIHA is caused by auto-antibodies directed against self red blood cell (RBC) surface antigens, resulting in intravascular hemolysis mediated by activated complement or extravascular hemolysis caused by destruction of complex of RBC with autoantibody in spleen and liver 3
Classification of AIHA
- The basic classification subdivides AIHA into primary/idiopathic and secondary with known underlying disease 3
- AIHA can also be classified according to the thermal range of antibody, recognizing warm AIHA, cold agglutinin disease (CAD), mixed AIHA, and paroxysmal cold hemoglobinuria 3, 4
Pathogenesis of AIHA
- The pathogenesis of AIHA consists of a defective antigen presentation to immunocompetent cells, insufficient process of T-lymphocyte tolerance to autoantigens, and induction of autoantibody production by B-lymphocytes 3
- Recent studies indicate the involvement of T and B cell dysregulation, reduced CD4+ and CD25+ Tregs, increased clonal expansions of CD8 + T cells, imbalance of Th17/Tregs and Tfh/Tfr, and impaired lymphocyte apoptosis 4
Diagnosis and Treatment of AIHA
- The diagnosis of AIHA is essential using direct and indirect antiglobulin tests 3
- The first-line therapy for warm AIHA is still administration of corticosteroids, while rituximab or splenectomy are used as second-line treatment for non-responding patients 3, 5, 6
- Reduction of erythrocyte destruction via splenectomy is currently the third line of treatment for warm AIHA 4