AQP4 and neuromyelitis optica: By contrast, previous studies have demonstrated the presence of eosinophil attractants in the CSF of patients with NMO [86], eosinophilic infiltration in NMO lesions [68], and the presence of eosinophils in 10–15% of acute CSF samples from patients with AQP4-IgG-positive NMOSD [55].