Interestingly, patients with NMO rarely present with positivity to myeloperoxidase antineutrophil cytoplasmic antibodies (MPO-ANCA) has been reported.[4] MPO-ANCA is an autoantibody to the cytoplasm of neutrophils, and it is often positive in the serum of patients with MPA. This evidence concerns the gene MPO and neuromyelitis optica.