[Clinical and imaging characteristics and influencing factors of myelin oligodendrocyte glycoprotein antibody-associated disease with different IgG antibody conversions].

<b>Objective:</b> To investigate the clinical and imaging characteristics of patients with myelin oligodendrocyte glycoprotein antibody (MOG-IgG)-associated disease (MOGAD) with different MOG-IgG seroconversions, and to analyze the factors affecting the conversion. <b>Methods:</b> Retrospective study. Patients diagnosed with MOGAD in the Department of Neurology, Beijing Tongren Hospital, Capital Medical University from January 2019 to April 2023 were included and the follow-up ended in May 2024. The clinical and imaging characteristics of MOG-IgG negative conversion group and non-negative conversion group were compared. A multivariate logistic regression model was used to analyze the influencing factors of MOG-IgG negative conversion. <b>Results:</b> A total of 51 patients were enrolled, including 23 males and 28 females, aged (38.3±16.4) years. There were 14 cases (27.5%) in the negative conversion group and 37 cases (72.5%) in the non-negative conversion group. The proportion of patients with initial serum MOG-IgG titer<1∶100 (10/14) and the proportion of patients with first attack (11/14) at the inception in the negative conversion group were higher than those in the non-negative conversion group [40.5% (15/37), 21.6% (8/37), <i>P</i><0.05]. The annual relapse rate (ARR) of the negative conversion group was [<i>M</i>(<i>Q</i>₁, <i>Q</i>₃)]0 (0, 0.2) and was significantly lower than that of the non-negative conversion group 0.5(0.1, 1.0) (<i>P</i>=0.001). No spinal cord involvement was found in the clinical classification and imaging of the negative conversion group, and 7/14 of the optic nerve MRI was only involved in the intraorbital segment, which was higher than that of the non-negative conversion group [13.5%, (5/37), <i>P</i>=0.018]. The median follow-up time was 18.1 (14.3, 37.3) months, and the median time from initial onset to serum MOG-IgG negative was 4.5 (2.8, 11.5) months in the negative conversion group, two cases in the negative conversion group relapsed after continuous negative conversion, one case relapsed with MOG-IgG positive and the other with negative. The first attack at the inception (<i>OR</i>=86.788, 95%<i>CI</i>: 1.436-5 244.198, <i>P</i>=0.033) and the low initial serum MOG-IgG titer (<i>OR</i>=10.840, 95%<i>CI</i>: 1.239-94.845, <i>P</i>=0.031), the more likely MOG-IgG seroconversion would be negative. <b>Conclusions:</b> Only the orbital segment of the optic nerve involvement without spinal cord involvement was more common in patients with MOG-IgG negative conversion. MOGAD patients with a first clinical attack and low initial MOG-IgG titer were more likely MOG-IgG seroconversion negative.