AQP4 and autoimmune disease: ANAs were reported to be more frequently exist in NMO‐IgG‐seropositive patients (Pittock et al., 2008), while another report also showed that patients with AQP4(+) were more likely to have coexisting autoantibodies (45/97, 46,4%) and autoimmune disorders (31/130, 23.8%) (Jarius et al., 2012).