AQP4 and systemic lupus erythematosus: In addition, AQP4-IgG1 antibodies have been proven to present in patients’ serum several years before the first NMOSD attack with SLE, and the elevation of anti-AQP4 might be a part of a polyclonal B-cell response during NMOSD relapses; Th1 responses also accompany autoantibody responses in the process of NMOSD/SLE (24).