It has been reported that AQP4‐Ab was detectable in 84.6% patients with SLE and NMO or LETM/rON and in 62.5% patients with other CTD and NMO or LETM, which showed the coexisting relationship between other autoimmune diseases and AQP4‐Ab‐positive NMOSD patients (Jarius et al., 2011). Here, AQP4 is linked to systemic lupus erythematosus.