MOG antibody-associated optic neuritis in the setting of acute CMV infection

A previously healthy 39 year old man was admitted to our hospital with subacute pain and blurred vision in the right eye, in the absence of fever. Physical exam was notable for mydriasis and relative afferent pupillary defect of the right pupil. Visual acuity was 0.5 in the right eye and 1.0 in the left eye. Funduscopic examination of the right eye revealed mild papilledema without concurrent retinitis. Evoked visual potentials were markedly decreased in amplitude on the right side, with P100 latency difficult to assess. Brain MRI revealed longitudinally extensive involvement of the intraorbital segment of the right optic nerve, as well as one periventricular white matter lesion. Spinal MRI was normal. Cerebrospinal fluid (CSF) analysis disclosed slight dysfunction of the blood-CSF barrier as evidenced by an albumin quotient of 6.9 (age-adjusted upper limit 6.5). CSF cell and protein levels were normal, without oligoclonal bands. The presence of papillitis prompted the search for an infectious trigger. Positive serum anti-CMV IgM antibodies were found, along with low avidity IgG antibodies (Fig. 1 a,b) and a low CMV viral load (whole blood CMV PCR 300 copies/ml). CSF CMV PCR was negative and there was no evidence of intrathecally produced anti-CMV-antibodies. CSF PCR for HSV, EBV and VZV were negative. HIV, HBV, HCV, EBV, T. pallidum, T. gondii, or B. burgdorferi infections as well as an underlying immune deficiency or connective tissue disease were excluded. The presence of optic neuritis with papillitis in the setting of non-specific brain MRI findings and absent CSF oligoclonal bands also led us to test for the presence of anti-aquaporin-4 and anti-MOG-antibodies. Anti-MOG IgG antibodies were detected in the serum by cell-based assay (CBA) [1]. Their presence was confirmed by a second, independent and blindly analyzed CBA. CSF was negative for anti-MOG-antibodies. Serum and CSF were both negative for anti-aquaporin-4 antibodies (CBA, Euroimmun, Lübeck, Germany). Antiviral therapy with Ganciclovir 5 mg/kg/12 h IV for 4 days was given in combination with Methylprednisolone 1 g/day IV for 3 days. This was followed by oral antiviral therapy with Valganciclovir 900 mg twice daily for two weeks. There was full recovery of visual acuity and MRI at 6 months follow-up revealed improvement in right optic neuritis. Longitudinal follow-up of anti-CMV antibodies showed decreasing titers of IgM antibodies with increasing titers of IgG antibodies, paralleled by an increase in anti-CMV IgG avidity (Fig. 1 a,b) and disappearance of CMV viremia. Anti-MOG antibodies were undetectable at 3 and 6 months follow-up (Fig.1 c).