Clinical manifestations of neuromyelitis optica in male and female patients

Neuromyelitis optica (NMO) is a severe, idiopathic, immuno-mediated, inflammatory demyelinating disease of the central nervous system. We examined the clinical features between male and female NMO patients, for which not much data exist. One hundred and eight Chinese Han patients with NMO were analysed retrospectively, all had been detected for the aquaporin-4 (AQP4) antibody using a cell-based assay. Of 108 NMO patients, 92 were female and 16 were male (female/male = 5.75). Ninety-four (87%) were positive for the AQP4 antibody in their serum and/or cerebral spinal fluid. Aquaporin-4 antibody-positive NMO patients had a higher female/male ratio than the negative group (P = 0.001). Female NMO patients had a higher positive rate of the AQP4 antibody than male NMO patients (92.4 vs 56.3%, P = 0.001). All NMO male patients were divided according to their AQP4 antibody status. 77.8% (7/9) of patients in the seropositive group had initial optic neuritis, while only one patient (14.3%, 1/7) in the negative group had optic neuritis (P = 0.041). Limb paraesthesia was reported in only one patient in the negative group (11.1%), but it was reported in all patients in the positive group (100%) (P = 0.001). The mean length of vertebral segments of the spinal cord lesions was 3.6 +/- 1.3 in the positive group, while it was 6.6 +/- 2.6 in the negative group (P < 0.0001). The involvement of the cervical spinal cord was found in 88.9% (8/9) of the positive members, but only 11.1% in the negative group (P = 0.009). However, the involvement of the thoracic spinal cord was found in 22.2% of patients in the positive group and 85.7% of patients in the negative members (P = 0.041). In conclusion, male NMO is rare and has a low positive rate of AQP4 antibody.