Clinical stabilization and effective B-lymphocyte depletion in the cerebrospinal fluid and peripheral blood of a patient with fulminant relapsing-remitting multiple sclerosis.

BACKGROUND The anti-CD20 monoclonal antibody rituximab effectively depletes B lymphocytes and has been successfully used in the therapy of immune-mediated disorders of the peripheral nervous system. A limited effect of rituximab on B lymphocytes in the cerebrospinal fluid compartment of patients with primary progressive multiple sclerosis (MS) was recently reported. OBJECTIVE To determine the effect of rituximab on clinical, magnetic resonance imaging, and immunological variables in a patient with relapsing-remitting MS. DESIGN A patient with relapsing-remitting MS was treated with rituximab. The patient was repeatedly examined clinically and by magnetic resonance imaging. The frequency of peripheral blood and cerebrospinal fluid B lymphocytes was assessed by flow cytometry before, during, and after rituximab therapy. RESULTS Rituximab monotherapy resulted in significant clinical improvement. Inflammatory surrogate markers on magnetic resonance imaging were also reduced. B lymphocytes were depleted in the cerebrospinal fluid and peripheral blood. CONCLUSIONS Our data demonstrate beneficial clinical effects of rituximab in relapsing-remitting MS, mediated through modulation of humoral systemic and central nervous system intrinsic immune responses. Clinical trials should determine optimal therapeutic strategies for patients with relapsing-remitting MS.