AQP4 and systemic lupus erythematosus: NMOSD is associated with an autoimmune disease in up to 33% of patients, with SLE being among the more common [2]. Often times neurologic complications in those with an established rheumatologic condition are attributed to the rheumatologic condition; however, the presence of AQP4-IgG indicates the co-existence of NMOSD, such as in this patient [7].