Overview of the rationale for immunomodulating therapies in multiple sclerosis.

The presence of mononuclear inflammatory cells within the nervous system first led to the hypothesis that an immunopathologic mechanism is involved in the pathogenesis of multiple sclerosis (MS). While there is now quite convincing evidence that MS is an immunologically mediated disease, many questions relevant to the use of immunomodulating therapy remain to be answered. These pertain to both the etiology and the exact immunopathologic mechanism involved. In addition, the inability to identify a specific target antigen for MS has implications for therapy. Despite these considerations, however, a rationale exists for the further evaluation of immunosuppressive therapies in this disease. However, it is prudent to limit use of such therapy to agents that can be shown to clearly produce sufficient clinical benefit in controlled studies to offset potential long-term risks in this chronic disease.