B-cell related biomarkers associated with severity of the first demyelinating event of acute optic neuritis.

Background: Optic neuritis (ON) is the most common cause of acute unilateral visual loss in young adults and frequently occurs as the presenting symptom of multiple sclerosis (MS). Recently, we reported activation of peripheral blood CD19 + ‏ B-cells in the early stage of ON. In the current study we aimed to identify peripheral blood ‏B-cell molecular markers associated with ON severity and visual outcome.

Methods: Expression of B-cell related biomarkers were analysed in patients with the first clinical presentation of acute unilateral ON. Logarithm of the Minimum Angle of Resolution (LogMAR). visual acuity, Optical Coherence Tomography (OCT) imaging, Expanded Disability Status Scale (EDSS) visual score and visual evoked responses were evaluated at onset and visual acuity and EDSS visual score were repeated at 6 months post-ON.

Results: Thirty patients with acute unilateral ON, 77% female, mean age 33 ± 2.0 years, were enroled in the study. Expression of CD19, CD79A and CD20 B-cell markers significantly correlated with LogMAR visual acuity of the affected eye (r = 0.44, p = 0.01, r = 0.37, p = 0.01 and r = 0.36, p = 0.04, respectively). The marker levels were elevated between 1.5 and 2.2-folds in the group with worse visual acuity (LogMAR>1.0) at onset (CD79A:×1.5, p = 0.013; CD19:×2.25, p = 0.007; CD20:×1.5, p = 0.015) and not correlated with 6 month visual outcome.

Conclusions: Among patient with a first event of acute ON, expression of B-cell biomarkers correlated with the severity of the disease. These results could add information on the role of B-cell dysfunction in the early stages of ON.