Master Warm Agglutinin Autoimmune Hemolytic Anemia (W-AIHA) with Picmonic for Medicine

Warm agglutinin autoimmune hemolytic anemia occurs when IgG autoantibodies react against the surface of RBCs at body temperature, 37 degrees celsius. It is the most common form of autoimmune hemolytic anemia.

At warm temperatures equal to or greater than 37 degrees celsius, the average human body temperature IgGs coat RBCs. The Fc portion of the immunoglobulin sitting on the RBC is recognized by macrophages, both from the spleen and liver. Macrophages sequester these RBCs and hemolyze them extravascularly.

At warm temperatures equal to or greater than 37 degrees celsius, the average human body temperature IgGs coat RBCs. The Fc portion of the immunoglobulin sitting on the RBC is recognized by macrophages, both from the spleen and liver. Macrophages sequester these RBCs and hemolyze them extravascularly. The IgG autoantibodies may also fix complement on the RBCs, enhancing the hemolysis.

At warm temperatures equal to or greater than 37 degrees celsius, the average human body temperature IgGs coat RBCs. The Fc portion of the immunoglobulin sitting on the RBC is recognized by macrophages, both from the spleen and liver. Macrophages sequester these RBCs and hemolyze them extravascularly. The IgG autoantibodies may also fix complement on the RBCs, enhancing the hemolysis.

Various medications can precipitate the formation of warm agglutinin autoantibodies. These include alpha-methyldopa, cephalosporins, diclofenac, ibuprofen, and levodopa. Some drugs stimulate the production of IgG autoantibodies, while others attach the RBC surface membrane and form haptens that induce IgG production.

Various medications can precipitate the formation of warm agglutinin autoantibodies. These include alpha-methyldopa, cephalosporins, diclofenac, ibuprofen, and levodopa. Some drugs stimulate the production of IgG autoantibodies, while others attach the RBC surface membrane and form haptens that induce IgG production.

Some studies have shown that greater than 10% of patients with chronic lymphocytic leukemia also develop warm agglutinin autoimmune hemolytic anemia. CLL patients that are treated with purine analogs may be at an increased risk.

SLE is associated with warm agglutinin autoimmune hemolytic anemia. Patients may also have a positive Coombs test without any clinical evidence of hemolysis.

The Coombs test detects if a patient has formed autoantibodies to their RBCs. A Direct Coombs test involves mixing a patient’s RBCs with test serum containing anti-IgG antibodies. If a patient has W-AIHA, their RBCs will be coated in IgG and anti-IgG in the test serum will agglutinate the RBCs; this reaction is referred to as a positive Coombs test.

Corticosteroids are used to treat many autoimmune conditions, including W-AIHA. Treatment helps to decrease antibody formation and increase hemoglobin. Approximately half of patients require long-term treatment with steroids.

Because much of the extravascular hemolysis in W-AIHA occurs in the spleen, splenectomy is the preferred second-line treatment for patients with W-AIHA refractory to corticosteroids.

IVIG, or intravenous immune globin, has limited efficacy for treatment and is employed in refractory cases resistant to corticosteroids.

Rituximab is a monoclonal antibody that works against B-cells, which produce autoantibodies. This drug is also a second-line treatment for patients who fail corticosteroids.