Initial use of alemtuzumab in multiple sclerosis (MS) was in patients with secondary progressive disease. Just as the efficacy experience of alemtuzumab generated some novel concepts of MS biology, such as the possibility of neuroprotective autoimmunity, so too has exploration of its adverse effects. The most significant adverse effect of alemtuzumab is secondary autoimmunity. A straightforward conclusion from the experience of using alemtuzumab, both open-label and within trials, is that it has the potential to be one of the most efficacious treatments of MS to date. A key lesson from the history of alemtuzumab treatment of MS has been that the disease is only vulnerable to such anti-inflammatory treatments early in its course, before the conditions that predispose to neurodegeneration, and secondary progression, have been set up. The finding of disability improvement after alemtuzumab suggests a new treatment paradigm in MS. There is no signal that alemtuzumab causes neoplasia.

In childhood-onset multiple sclerosis (MS), the cerebrospinal fluid (CSF) profile is not fundamentally different from the adult-onset MS. Magnetic resonance imaging (MRI) is the best imaging technique to detect lesions suggestive of MS in children. The initial clinical course in most patients with childhood-onset MS is relapsing-remitting. In the UCSF cohort, the initial MS event was moderate or severe in 86% of children compared with 56% of adult-onset MS. In the UCSF pediatric-onset cohort, complete recovery was seen in 66%, which was similar to adults seen at the same center, questioning whether children have less irreversible neuronal injury during their first event or/and have a better ability to repair. MS is likely the result of a complex interplay between genes and environment. Potential prognostics factors associated with the assignment of disability milestones have been examined in several cohort studies from adult centers and one cohort from child neurology centers.