Cold agglutinin disease (CAD) is a rare autoimmune disorder in which autoantibodies bind to red blood cells (RBCs) at low temperatures. This causes the RBCs to clump, triggering the immune system to attack them. As a consequence, RBCs are depleted and patients become anemic.
No treatment is necessary in mild cases of CAD. Avoiding cold temperatures or living in regions with warmer climates can help to prevent the binding of autoantibodies to RBCs. Folic acid supplements are also advisable because this vitamin is essential for the formation of red blood cells.
In more serious or severe cases, treatment may be necessary. These are summarized below.
Treatment with Rituximab
Rituximab is an antibody that binds to the immune cells that produce autoantibodies (autoantibodies being antibodies — immune system proteins — that mistakenly target and react with a person’s own tissues or organs). With fewer autoantibodies around to bind to RBCs, there’s lesser clumping of these blood cells and fewer immune attacks
Rituximab is used as a first-line treatment for CAD, and is effective as a monotherapy in about half of all cases. The medicine’s effects usually lasts for 11 months.
Rituximab can also be combined with the chemotherapeutic agent fludarabine. The response rate of the combined treatment is higher than that with rituximab alone (76 percent), and the period of remission longer (5.5 years on average). Side effects, which can be severe, are a key disadvantage and a reason that treatment with rituximab alone is preferred.
This medication can also be combined with immunosuppressive drugs such as cyclophosphamide or prednisone when other approaches are not effective.
Plasmapheresis
Plasmapheresis, also known as plasma exchange, is a procedure for filtering plasma to remove antibodies and clotting factors from the blood. In patients with CAD, it is used to reduce the number of antibodies against red blood cells. Plasmapheresis may only be a temporary solution, however, because antibody-producing immune cells are not removed through this process.
Blood transfusions
Blood transfusions are performed only in extreme cases, when the levels of hemoglobin (the protein that carries oxygen in red blood cells) drop below 7 g per dl, and the antibody titer is high. The procedure is not without risk because complement proteins (a type of plasma protein) in the transfused blood can cause hemolysis (the destruction of red blood cells). It is crucial that warm blood is used for transfusion.
Treatment with erythropoietin
Erythropoietins, such as Procrit, Epogen, and Aranesp, may be given to CAD patients to raise hemoglobin levels. Their use is not without risk, and excessive use can lead to conditions associated with a rapid rise in hemoglobin concentrations, including cardiovascular events and thrombosis (blood clots).
Last updated: August 10, 2019
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