DMD is caused by a genetic defect that results in the loss of a key muscle protein and isn't thought of as an immunologic disorder. However, researchers have theorized that there may be some immunologic problem in Duchenne. Whenever tissues degenerate in the body, the immune system gets involved to some extent in "cleaning up" the debris. Sometimes, this cleanup effort, though necessary, tips the balance toward an autoimmune, or "self-immune," response, either inflammation or an even more complete immunologic attack on some of the body's own tissues.
In DMD, where muscle fibers are breaking down and exposing their usually enclosed contents to the immune system's surveillance, it has seemed likely that the immune system might be a culprit in some of the final stages of muscle destruction.
After the benefits of prednisone were noted, researchers decided to study the drug azathioprine (Imuran), an immunosuppressant used in many diseases. Unfortunately, the drug didn't show any benefit in Duchenne. Another drug that's been studied is cyclosporine (Sandimmune). A small study in 1993 suggested this drug might increase strength in boys with DMD, but later investigation failed to confirm this early result.
Immunosuppressants are dangerous drugs. They all interfere with the body's ability to fight off routine infections. Chicken pox could be particularly dangerous. Many have other serious side effects, including increasing the risk of cancer.
Most doctors believe their use in Duchenne at this time doesn't seem worth the risks.
