Ocrelizumab does not impair B- and T-cell responses to primary VZV infection in a patient with MS

Ocrelizumab has been recently approved for relapsing-remitting MS, demonstrating a dramatic effect on MRI and clinical parameters in 2 pivotal phase III trials.1 However, long-term B-cell depletion might lead to an increased susceptibility to infections and/or to their increased severity (a case of fulminant hepatitis due to enterovirus infection has been recently reported by our group).2 Finally, depletion of B-cell compartment might impair acquisition of long-term humoral immunologic memory (i.e. production of antigen-specific class G immunoglobulins [IgG]) and might reduce T-lymphocyte response because of the absence of B lymphocyte–mediated activation. Indeed, humoral response to vaccination has been shown to be dampened or abolished in ocrelizumab-treated patients.3