In many ways, multiple sclerosis (MS) is among the most frustrating and vicious of human diseases. Although we can readily see the demyelinating effect of MS lesions on postmortem examination, the diagnosis during life is fraught with difficulty. Advances in cerebrospinal fluid analysis and neuroimaging techniques have contributed to a recent revision of diagnostic criteria for MS, yet the majority of patients still wait for years until a definitive diagnosis is reached. They then face a disease that is both highly unpredictable and, in most cases, severely debilitating.

The unpredictable nature of MS is particularly distressing and many patients exist in a persistent state of fear and anxiety about their next MS exacerbation. Despite improved treatments, MS leaves some of the most severely affected patients wheelchair-bound by their early twenties. The more fortunate ones learn to deal with sporadic functional impairments for the rest of their lives. The unpredictable nature of MS leaves its victims always wondering about the next phase of their illness. For some, a more negative but definitive prognosis would be easier to accept than one for which the outcome is so unclear.

To make matters worse, the cause of MS remains an elusive one. Research points to an infectious and/or autoimmune etiology. The disorder is more common among those living in northern hemispheres, afflicts women more often than men, and has a partial genetic basis as evidenced by a greater concordance rate for monozygotic than dizygotic twins that nevertheless, falls far short of what would be expected of an autosomal, Mendelian disease. Drugs that modulate the immune system, from steroids to interferons, are somewhat helpful. Yet despite this, the long-term prognosis for MS has not changed much in recent decades and no therapy exists that addresses the root pathophysiology of the disease—demyelination.