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.
The persistence of neurological symptoms after SARS-CoV-2 infection, as well as the presence of late axonal damage, is still unknown. We performed extensive systemic and neurological follow-up evaluations in 107 out of 193 consecutive patients admitted to the COVID-19 medical unit, University Hospital of Verona, Italy between March and June 2020. We analysed serum neurofilament light chain (NfL) levels in all cases including a subgroup (n = 29) of patients with available onset samples. Comparisons between clinical and biomarker data were then performed. Neurological symptoms were still present in a significant number (n = 49) of patients over the follow-up. The most common reported symptoms were hyposmia (n = 11), fatigue (n = 28), myalgia (n = 14), and impaired memory (n = 11) and were more common in cases with severe acute COVID-19. Follow-up serum NfL values (15.2 pg/mL, range 2.4–62.4) were within normal range in all except 5 patients and did not differentiate patients with vs without persistent neurological symptoms. In patients with available onset and follow-up samples, a significant (p < 0.001) decrease of NfL levels was observed and was more evident in patients with a severe acute disease. Despite the common persistence of neurological symptoms, COVID-19 survivors do not show active axonal damage, which seems a peculiar feature of acute SARS-CoV-2 infection.
acknowledgements the authors thank Quanterix Corporation for providing technical assistance. and print the article for any lawful, non-commercial purpose (including text and data mining) provided that all copyright notices and trade marks are retained.
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