Cold antibody hemolytic anemia (CAHA) is a rare autoimmune disorder characterized by the premature destruction of red blood cells (rbcs) by the body's natural defenses against invading organisms (antibodies). Normally, the red blood cells have a life span of approximately 120 days before they are destroyed by the spleen. In individuals with CAHA, the red blood cells are destroyed prematurely and the rate of production of new cells in the bone marrow can no longer compensate for their loss. The severity of the anemia is determined by the length of time that the red blood cells survive and by the rate at which the bone marrow continues to create new red blood cell production.
The immune hemolytic anemias are classified according to the optimal temperature at which the antibodies act to destroy red blood cells. As their names imply, cold antibody hemolytic anemia occurs at temperatures of approximately 0 to 10 degrees centigrade, while warm antibody hemolytic anemia (WAHA) occurs at temperatures of 37 degrees centigrade or higher.
In most cases, CAHA is a primary disorder that typically becomes apparent at 50 to 60 years of age. Symptoms and findings associated with the disorder may include fatigue; low levels of circulating red blood cells (anemia); persistent yellowing of the skin, mucous membranes, and whites of the eyes (jaundice); and/or sweating and coldness of the fingers and/or toes (digits) and uneven bluish or reddish discoloration of the skin of the digits, ankles, and wrists (acrocyanosis or Raynauds sign).
Cold antibody hemolytic anemia may also occur as a secondary disorder in association with a number of different underlying disorders such as certain infectious diseases (e.g., mycoplasma infection, mumps, cytomegalovirus, infectious mononucleosis), immunoproliferative diseases (e.g., non-Hodgkin's lymphoma, chronic lymphocytic leukemia), or connective tissue disorders (e.g., systemic lupus erythematosus). Although CAHA is known to be an autoimmune disorder, its exact underlying cause is not fully understood.