Master Cold Agglutinin Autoimmune Hemolytic Anemia (C-AIHA) with Picmonic for Medicine

Certain infections such as Mycoplasma pneumonia have both been associated with cold agglutinin autoimmune hemolytic anemia. Mycoplasma contains a specific antigen on its surface to which IgM autoantibodies bind, causing agglutination and hemolysis.

EBV is a rare cause of cold agglutinin autoimmune hemolytic anemia; autoantibodies form to the i-surface antigen.

Chronic lymphocytic leukemia, lymphoma, Waldenstrom's Macroglobulinemia, and other lymphoproliferative disorders are frequently associated with cold agglutinin autoimmune hemolytic anemia, as these patients’ RBC surfaces are more likely to contain certain antigens to which IgM cold agglutinins bind. In addition, these lymphoproliferative disorders may induce the synthesis of IgM cold agglutinins, leading to cold agglutinin autoimmune hemolytic anemia.

Livedo reticularis may also occur with cold agglutinin autoimmune hemolytic anemia and is described as having a purple-bluish lacy or mottled appearance.

In cold agglutinin autoimmune hemolytic anemia, agglutination and hemolysis tends to occur in peripheral locations on the body such as the fingers and toes. Skin color returns back to normal in these regions once it is warmed.

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-IgM antibodies. If a patient has cold agglutinin autoimmune hemolytic anemia, their RBCs will be coated in IgM and anti-IgM in the test serum will agglutinate the RBCs; this reaction is referred to as a positive Coombs test. The Coombs test will not demonstrate agglutination with IgG antibodies.

Because cold agglutinin autoimmune hemolytic anemia occurs below body temperature, patients should avoid the cold.

Rituximab is a monoclonal antibody against B cells, some of which produce autoantibodies.

Rituximab is typically used in combination with other immunosuppressants or other cytotoxic agents, such as fludarabine, a purine analog.