Is there a correlation between MOG‐associated disorder and SARS‐CoV‐2 infection?

BACKGROUND AND PURPOSE: Anti‐myelin oligodendrocyte glycoprotein antibodies (MOG‐Abs) distinguish a group of inflammatory disorders which can be preceded by specific or non‐specific infections. A few single cases have been reported in association with SARS‐CoV‐2 infection, but a specific study on the correlation between COVID‐19 and myelin oligodendrocyte glycoprotein (MOG)‐associated disorder (MOGAD) has not yet been performed. The aim of this study was to determine the impact of the pandemic on this condition. METHODS: We analysed SARS‐CoV‐2 serology in patients newly diagnosed with MOGAD (1 August 2020 to 31 May 2021). MOG‐Ab‐seronegative age‐ and time‐matched subjects were used as controls. SARS‐CoV‐2 immunoglobulin G (IgG) levels were analysed using an anti‐SARS‐CoV‐2 US Food and Drug Administration‐approved ELISA assay and confirmed with a trimeric anti‐SARS‐CoV‐2 S1/S2 IgG immunochemiluminescent test, concomitantly assaying the anti‐receptor binding domain (RBD) of spike protein IgG and anti‐RBD total Ig. We actually compared the number of cases referred in each of the last 3 years. RESULTS: Presence of SARS‐CoV‐2 IgG antibodies was more common (12/30, 40%) in MOGAD patients than in controls (6/30, 20%), although the difference was not significant (p = 0.16; odds ratio 2.67, 95% confidence interval 0.85–9.17). The most common clinical presentations of MOGAD SARS‐CoV‐2‐seropositive patients included optic neuritis (n = 6) and myelitis (n = 3). The number of diagnosed cases increased over the last 3 years, in particular, when including cases referred to us before the COVID‐19 pandemic, in the initial phase of the first wave and in the late phase of the second wave (n = 9, rate 10.6% in 2019; n = 13, rate 12.3% in 2020; n = 15, rate 14.7% in 2021). CONCLUSION: Our findings provide preliminary data on SARS‐CoV‐2 as a potential trigger of MOGAD.