Immunologic therapy for secondary and primary progressive multiple sclerosis.

Multiple sclerosis (MS) is generally considered an immune-mediated demyelinating disease, and treatments designed to modify the course of MS are immunosuppressive or immunomodulatory. Although most people with MS have a relapsing-remitting course initially, the majority will eventually experience a more gradual decline in neurologic function, termed secondary progressive MS. Some patients have gradual worsening from the beginning, termed primary progressive MS. Recent pathologic studies have revealed that axonal injury and neuronal degeneration are much more prominent in MS than previously recognized, and may be the explanation for the gradual decline in neurologic function that characterizes progressive MS. The results of several clinical trials in MS indicate that suppression of the immune-mediated inflammation may decrease the relapse rate in MS, but not stop the progressive loss of neurologic function. There are many promising approaches to this clinical dilemma, but none has been proven to be effective in stopping or retarding progressive MS. More well-designed, controlled, blinded, randomized clinical trials are needed to test these putative therapies. In the mean time, we should avoid subjecting patients to potentially dangerous and unproven regimens.