Cold agglutinin disease (CAD)

Cold agglutinin disease (CAD) is a rare, severe blood disorder. It’s a form of autoimmune hemolytic anemia, which means the immune system mistakenly attacks and destroys red blood cells. In cold agglutinin disease, certain abnormal bone marrow cells produce antibodies called cold agglutinins, which activate a part of the immune system known as the complement pathway. This activation results in the constant destruction of red blood cells, known as hemolysis.  Cold agglutinin disease can be primary (unknown cause) or secondary, due to an underlying condition such as an infection, another autoimmune disease, or certain cancers.