Rituximab is a genetically engineered chimeric murine/human monoclonal antibody that targets CD20, a B-cell-specific surface antigen. It was the first monoclonal anti-CD20 antibody to be approved for
medical use in human diseases. It was initially licensed for non-Hodgkin‟s lymphoma and then made available for chronic lymphocytic leukemia, rheumatoid arthritis, granulomatosis with polyangiitis, and microscopic polyangiitis. RTX was also successfully used off-label to treat neuromyelitis optica spectrum disorders, MS, myasthenia gravis, autoimmune encephalitis, autoimmune neuropathies, and myopathies.