I appreciate the correspondence by the 2 sets of authors who describe patients with 1 or 2 systemic autoimmune diseases who later developed a classic syndrome of relapsing NMO. The association of systemic autoimmunity with NMO has been recognized by us and by others,1,2 especially in patients with systemic lupus erythematosus and Sjögren disease.3 Neuromyelitis optica may coexist with myasthenia gravis,4 idiopathic thrombocytopenic purpura, or multiple autoimmune diseases. The predilection of patients with NMO to develop multiple autoimmune diseases is not understood.
Weinshenker BG. Neuromyelitis Optica and Autoimmune Diseases—Reply. Arch Neurol. 2008;65(7):992-996. doi:10.1001/archneur.65.7.996