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Complications of Replacement Therapy

Complications of replacement therapy include:

- Developing antibodies (proteins) that attack the clotting factor
- Developing viral infections from human clotting factors
- Damage to joints, muscles, or other parts of the body resulting from delays in treatment

Antibodies to the clotting factor.

Antibodies can destroy the clotting factor before it has a chance to work. This is a very serious problem. It prevents the main treatment for hemophilia (replacement therapy) from working. These antibodies, also called inhibitors, develop in about 20-30 percent of people who have severe hemophilia A. Inhibitors develop in 2-5 percent of people who have hemophilia B
When antibodies develop, doctors may use larger doses of clotting factor or try different clotting factor sources. Sometimes the antibodies go away. Researchers are studying new ways to deal with antibodies to clotting factors.

Viruses from human clotting factors.

Clotting factors made from human blood can carry the viruses that cause HIV/AIDS and hepatitis. ....I.... , the risk of getting an infectious disease from human clotting factors is very small due to:

- Careful screening of blood donors
- Testing of donated blood products
- Treating donated blood products with a detergent and heat to destroy viruses - Vaccinating people who have hemophilia for hepatitis A and B

Damage to joints, muscles, and other parts of the body.

Delays in treatment can cause damage such as:

- Bleeding into a joint. If this happens many times, it can lead to changes in the shape of the joint and impair the joint's function.
- Swelling of the membrane around a joint. - Pain, swelling, and redness of a joint.
- Pressure on a joint from swelling, which can destroy the joint.

(Adapted from http://www.nhlbi.nih.gov/health/health-topics/ topics/hemophilia/treatment.html)