Cold agglutinin disease (CAD)

Cold agglutinin disease (CAD) in the glossary for Waldenström's macroglobulinemia

A rare hematological condition in which the immune system destroys erythrocytes.

Cold agglutinin disease (CAD) is a rare autoimmune disease characterized by the presence of high concentrations of circulating cold sensitive antibodies, usually IgM and autoantibodies that are also active at temperatures below 30 °C, directed against erythrocytes, causing them to agglutinate and undergo lysis. It is a form of autoimmune hemolytic anemia, specifically one in which antibodies bind erythrocytes only at low body temperatures (typically 28–31 °C). When an affected individual's blood is exposed to cold temperatures (0 °C to 10 °C), IgM antibodies attach themselves to erythrocytes and bind them together into clumps (agglutination). This eventually causes erythrocytes to be prematurely destroyed (hemolysis) leading to anemia and other associated signs and symptoms. Signs and symptoms of hemolytic anemia may include fatigue, dizziness, headaches, cold hands and feet, pale skin, dark urine, jaundice, chest pain, pain in the back or legs, vomiting, diarrhea, and heart problems such as arrhythmia (an irregular heartbeat), a heart murmur, an enlarged heart, or heart failure.