Seroprevalence of NMO-IgG among patients with neuromyelitis optica and opticospinal multiple sclerosis

Objectives

In this study we sought to compare the seropositivity of NMO-IgG in patients presenting with demyelinative involvement of optic nerve and spinal cord with and without longitudinally extensive spinal cord lesion (LESCL).

Methods

Patients who were referred to Isfahan Multiple Sclerosis Clinic and Isfahan Devic's Disease Clinic at Al-Zahra Hospital in Iran were screened for this study. Patients with signs and symptoms indicating the demyelinating involvement of optic nerve(s) and spinal cord were included. Patients were evaluated by a neurologist and spinal cord and brain magnetic resonance imaging (MRI) were obtained. Patients with normal first brain MRI and with spinal cord demyelinative lesions visible on spinal MRI were included. Patients were then put into two groups: (i) patients with LESCL [neuromyelitis optica (NMO)] and (ii) patients with spinal plaques which do not extend over three vertebrae [opticospinal multiple sclerosis (OSMS)]. NMO-IgG was measured in the serum of the included patients.

Results

Totally we recruited 33 patients with LESCL and 32 patients without LESCL. The mean age of patients without LESCL was 34.61 ± 10.98 and it was 33.48 ± 11.93 for the NMO patients. In both groups there were 24 females and the rest were males. Among the NMO patients 16 (48.5%) were positive for NMO-IgG, while in the OSMS group there were none.

Conclusion

The results of this study are in line with previous observations, and imply that the presence of LESCL is associated with the presence of NMO-IgG and thus an indicator of NMO.