Severe relapses after the first infusion of natalizumab in active relapsing-remitting multiple sclerosis

Abstract We describe three patients suffering from a very active form of relapsing-remitting multiple sclerosis (MS), who experienced severe disease worsening, associated with a marked increase in brain inflammation, a few days after the first administration of natalizumab. In line with preclinical studies, our observations suggest that natalizumab, when administered during active disease phases, may worsen disease evolution possibly by modifying the regulatory network in the brain. We suggest that relapsing-remitting MS patients having had a recent relapse should be treated with natalizumab only after achieving complete clinical and radiological remission

Therapeutic anti-integrin (α4 and αL) monoclonal antibodies: two-edged swords?

Anti-α4 and anti-αL integrin chain monoclonal antibodies have shown a clear-cut beneficial effect in different animal models of autoimmune and inflammatory disorders as well as in human diseases, including multiple sclerosis, inflammatory bowel disease, and psoriasis. It has been widely assumed that this therapeutic effect is mainly consequence of the blockade of leucocyte adhesion to endothelium, inhibiting thus their extravasation and the inflammatory phenomenon. However, it is evident that both α4β1 (very late antigen-4) and αLβ2 (leucocyte function-associated antigen-1) integrins have additional important roles in other immune phenomena, including the formation of the immune synapse and the differentiation of T helper 1 lymphocytes. Therefore, it is very feasible that the long-term administration of blocking agents directed against these integrins to patients with inflammatory/autoimmune conditions may have undesirable or unexpected effects