Importantly, AQP4 autoantibodies have been found to be present in the peripheral blood of SLE patients or in a single healthy individual, both without clinical evidence of NMOSD or CNS involvement (37, 43, 44); in the case of the healthy individual, NMOSD became clinically manifested 10 y later. This evidence concerns the gene AQP4 and systemic lupus erythematosus.