Cold agglutinin

Cold agglutinin disease is a rare type of autoimmune hemolytic anemia where the body's immune system mistakenly attacks and destroys its own red blood cells. This is caused by cold-reacting antibodies known as cold agglutinins.

Etiology

Cold agglutinin disease can be primary (idiopathic) or secondary, resulting from an underlying condition such as infection, lymphoproliferative disorder, or autoimmune disease. The most common infections associated with this condition are Mycoplasma pneumoniae and Epstein-Barr virus.

Pathophysiology

In cold agglutinin disease, the cold agglutinins bind to antigens on the surface of red blood cells at low temperatures, typically below 30°C. This binding leads to agglutination (clumping) and hemolysis (destruction) of the red blood cells.

Clinical Presentation

The symptoms of cold agglutinin disease are often triggered by exposure to cold temperatures. They can include fatigue, dyspnea (difficulty breathing), pallor (pale skin), and acrocyanosis (bluish discoloration of the extremities). In severe cases, it can lead to anemia, jaundice, and hemoglobinuria (presence of hemoglobin in urine).

Diagnosis

Diagnosis of cold agglutinin disease is based on the presence of high levels of cold agglutinins in the blood, detected by a cold agglutinin test. Other tests may include a complete blood count, direct antiglobulin test, and serum bilirubin level.

Treatment

Treatment of cold agglutinin disease is primarily aimed at managing symptoms and treating any underlying conditions. This may include avoiding exposure to cold, blood transfusion for severe anemia, and medications such as corticosteroids, rituximab, and immunosuppressive drugs.

See Also

• Autoimmune hemolytic anemia
• Paroxysmal cold hemoglobinuria
• Warm autoimmune hemolytic anemia