Factors Associated with MOG-IgG Serostatus Change
Katherine Havard1, Jeffrey Cohen2, Amy Kunchok3
1Cleveland Clinic Foundation, 2Cleveland Clinic, 3Cleveland Clinic - Mellen Centre
Objective:
To determine the frequency and factors associated with MOG-IgG serostatus change.
Background:
MOG-IgG is a diagnostic biomarker of myelin oligodendrocyte glycoprotein associated disorder (MOGAD). Factors associated with serostatus change are not well understood.
Design/Methods:
All patients tested for MOG-IgG by live Fluorescence-Activated Cell Sorting cell-based assay (live-CBA) or fixed-CBA between 2017-2024 with serial testing (≥2 tests) were included.
Results:

Of 3,857 patients, 265 had serial testing.  

Of 52/265 initially MOG-IgG+, 43 patients (81%; 35 adults, 8 children) were persistently MOG-IgG+ on serial testing (median duration 187 days). Treatments included corticosteroids (19), anti-CD20 (8), IVIG (6), mycophenolate (2), plasmapheresis (1), none (13).   

Of 52/265 initially MOG-IgG+, 9 (17%, 7 adults, 2 children) seroreverted (median 507 days, range 64-1709). 100% were tested by live-CBA.  Seroreverter diagnoses included MOGAD (6), MS (1), POTS (1), epilepsy (1). Initial titers were 1:20 (4), 1:40 (2), 1:100 (3). Treatments included rituximab (3), azathioprine (1), IVIg (1), none (4). A third test in 3 in 1 returned positive (1:100), and negative in 2. No seroreverters had further relapses (median follow up after seroreversion: 362 days). 

Of 213/265 initially MOG-IgG- (97% live-CBA, 3% fixed-CBA), 211 (99%) remained negative. 2 (1%) seroconverted to positive. The first seroconverted 26 days post-infectious onset of optic neuritis, with steroid treatment at time of first test, and steroids plus plasmapheresis before second test (negative to 1:100, both live-CBA).  The second seroconverted after 358 days (negative to 1:20, both fixed-CBA). They had 4 optic neuritis attacks over 5 years and received steroids 2 months preceding first negative test, but no treatment 14 months before seroconversion.

Conclusions:
Seroreversion occurred in 17%, was associated with titers ≤1:100 and no further relapses. Seroconversion was uncommon (1%). These results suggest potential utility of serial testing in patients initially MOG-IgG+ but low yield in patients initially MOG-IgG-.
10.1212/WNL.0000000000210493
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