[Rituximab (anti-CD20) in neurological disorders]

Rituximab is a chimeric murine/human monoclonal antibody that specifically targets CD20 molecules on the surface of B-cells, thereby depleting B-cells and regulating humoral immunity. This antibody is mostly used in CD20-positive B-cell lymphoma, but is also widely used in many other connective tissue and neurological disorders. These neurological disorders include multiple sclerosis, neuromyelitis optica, myasthenia gravis, Lambert-Eaton myasthenic syndrome, chronic inflammatory demyelinating polyradiculoneuropathy, paraneoplastic neurological syndromes, primary central nervous system lymphoma, inflammatory myopathy, and some other autoimmune-mediated neurological disorders. Rituximab may be useful even in refractory cases of these disorders. There are some notable side effects in each phase after administration. An infusion reaction can occur just after administration in more than half of cases, though most reactions are negligible. Several months after administration, sustained suppression of humoral immunity with myelosuppression can cause reactivation of Hepatitis B Virus (HBV) progressive multifocal leukoencephalopathy (PML), and severe opportunistic infections, some of which are fatal once they occur. Severe interstitial pneumonia can be treated with steroid pulse therapy, if necessary. To reduce the risk of infusion reactions and improve long-term tolerability, the human-derived components of the antibody have been increased to form humanized or human monoclonal antibodies like ocrelizumab and ofatumumab.