[The role of aquaporin 4 antibody in the injury of retinal microstructure in neuromyelitis optica spectrum disorders].

Objective: To evaluate the injury of retinal microstructure using optical coherence tomography (OCT) and investigate the role of aquaporin 4 antibody (AQP4 Ab) in this injury process. Methods: Forty patients with neuromyelitis optica spectrum disorders (NMOSD) were retrospectively studied, each of whom reported at least one episode of optic neuritis (ON), namely 59 ON eyes involved in all. All patients were divided into two subgroups based on AQP4 Ab tests including 25 patients (37 ON eyes) with AQP4 positive (Ab(+)/NMOSD group) and 15 patients (22 ON eyes) negative (Ab(-)/NMOSD group). In addition, 10 healthy controls (20 eyes) matched for age and sex (HC group) were analyzed. Spectral domain optical coherence tomography (SD-OCT) was used to quantify peripapillary retinal nerve fiber layer (RNFL). Nonparametric test was used to compare differences between groups. Results: Age distribution and gender ratio were comparable in three groups (P>0.05). Visual acuity in ON eyes of Ab(+)/NMOSD group was worse than that of Ab(-)/NMOSD group (P=0.02). There were no significant differences between Ab(+)/NMOSD and Ab(-)/NMOSD in aspects of disease duration (2.6 vs. 1.9 year), ON episodes (2 vs. 1), longitudinal extensive transverse myelitis (LETM) ratio (48.0% vs. 66.7%), NMOSD specific intracranial lesions ratio (32.0% vs. 53.3%), positive autoimmune antibody ratio (52.0% vs. 20.0%) (P= 0.13, 0.08, 0.25, 0.18, 0.06, respectively). The thickness of temporal, superior, nasal, inferior and average RNFL in ON eyes of both Ab(+)/NMOSD and Ab(-)/NMOSD group were thinner than those in eyes of HC group (all P<0.05). The thickness of superior and inferior RNFL in ON eyes of Ab(+)/NMOSD were 61.0 μm and 62.0 μm, which was thinner than those of Ab(-)/NMOSD 94.5 μm and 97.0 μm (P=0.03 and 0.01, respectively). Conclusions: RNFL reflects the injury of retinal microstructure in NMOSD patients. AQP4 Ab seropositivity is correlated to the severity of RNFL damage, implying the potential role of AQP4 Ab in this pathological process.