ObjectiveTo compare response to rituximab (RTX) between adult patients positive for myelin oligodendrocyte glycoprotein (MOG) and aquaporin‐4 (AQP4) antibodies.MethodsWe prospectively studied adult patients with MOG or AQP4 antibodies who received RTX under an individualized dosing schedule adapted to the biological effect of RTX monitored by memory B‐cell measurement. Memory B cells were counted monthly and when relapse occurred. The biological effect of RTX was considered significant with <0.05% memory B cells in peripheral blood lymphocytes.ResultsIn 16 patients with MOG antibodies and 29 with AQP4 antibodies, mean follow‐up was 19 (range = 9–38) and 38 (13–79) months. Under RTX, 10 relapses occurred in 6 of 16 (37.5%) patients with MOG antibodies, and 13 occurred in 7 of 29 (24%) with AQP4 antibodies. The median time of relapse after the most recent infusion was 2.6 (0.6–5.8) and 7 (0.8–13) months, respectively (p < 0.001). Memory B cells had reemerged in 2 of 10 (20%) relapses in patients with MOG antibodies and 12 of 13 (92.5%) with AQP4 antibodies (p < 0.001).InterpretationIn AQP4 antibody–associated disorder, relapse mostly occurs when the biological effect of RTX decreases, which argues for treatment efficacy. In MOG antibody–associated disorder, the efficacy of RTX is not constant, because one‐third of patients showed relapse despite an effective biological effect of RTX. In this subpopulation, memory B‐cell depletion was unable to prevent relapse, which was probably caused by different immunological mechanisms. These findings should be used to improve treatment strategies for MOG antibody–associated disorder. ANN NEUROL 2020;87:256–266

Background and ObjectivesTo determine the frequency of hypogammaglobulinemia and infections in patients with multiple sclerosis (PwMS) receiving rituximab (RTX).MethodsThis prospective observational study included all consecutive PwMS receiving RTX at the university hospital of Marseille, France, between 2015 and 2020. Patient visits occurred at least every 6 months.ResultsWe included 188 patients (151 with relapsing-remitting MS; the mean age was 43.4 years [SD 12.9], median disease duration 10 years [range 0–36], median Expanded Disability Status Scale 5 [range 0–8], median follow-up 3.5 years [range 1–5.8], and median number of RTX infusions 5 [range 1–9]). Overall, 317 symptomatic infections and 13 severe infections occurred in 133 of 188 (70.7%) and 11 of 188 (5.9%) patients, respectively. After 4 years, 24.4% of patients (95% CI 18.0–33.1) were free of any infection and 92.0% (95% CI 87.1–97.1) had not experienced a severe infection. At RTX onset, the immunoglobulin G (IgG) level was abnormal in 32 of 188 (17%) patients. After RTX, IgG level was <7, <6, <4 and <2 g/L for 83 (44%), 44 (23.4%), 8 (4.2%) and 1 (0.53%) patients, respectively. The risk of infection was associated with reduced IgG levels (multivariate Cox proportional hazards hazard ratio [HR] = 0.86, 95% CI 0.75–0.98, p = 0.03). The risk of reduced IgG level <6 g/L increased with age (HR = 1.36, 95% CI 1.05–1.75, p = 0.01).DiscussionIn PwMS receiving RTX, reduced IgG level was frequent and interacted with the risk of infection.

This study provides level IV evidence that rituximab reduces clinical and MRI disease activity in patients with active RRMS despite immunosuppressive DMT.

We studied the serologic response to the BNT162b2 mRNA vaccine at four weeks after the second dose in patients with RRMS treated with rituximab with extended-interval dosing ( n = 26). At four weeks, 73% of patients were seropositive. No patient without B cells at the first dose ( n = 4) was seropositive. Four of seven (57%) patients with B-cell proportion >0% and ≤5% were seropositive. All patients with B-cell proportion >5% ( n = 15) were seropositive. In all patients, quantitative ELISA measures after vaccination were correlated with B-cell counts measured before vaccination. In patients receiving rituximab, seropositivity after BNT162b2 mRNA vaccination emerged only after B-cell repopulation.

Background and ObjectivesPure relapsing short myelitis with clinical and paraclinical features suggesting multiple sclerosis (MS) has been described recently. Here, we evaluated the existence of this potential new form of MS by retrospectively searching for similar cases in the databases of the French tertiary MS centers.MethodsPatients were included based on the present criteria: at least 2 short (<3 vertebral segments) myelitis episodes; minimum follow-up of 3 years; no MS-like brain lesion during all the follow-up; tested negative for both anti–myelin oligodendrocyte glycoprotein and anti–aquaporin 4 antibodies in serum; presence of oligoclonal bands in CSF; and comprehensive workup to exclude alternative diagnoses.ResultsEighteen patients fulfilled all criteria. The sex ratio (females/males) was 5/1; the median (range) age at first relapse was 35.5 (25–54) years, the disease duration was 80.5 (50–308) months, and the annualized relapse rate was 0.36 (0.1–0.5). The median (range) number of relapses per patient was 2 (2–5), and the median (range) Expanded Disability Status Scale score at last follow-up was 1 (0–7.5). In CSF, the median (range) protein level was 0.34 g/L (0.18–0.77), and the median (range) number of mononuclear cells was 3 (0–28). Spinal cord MRI demonstrated a median (range) number of 2 (1–5) lesions per examination and 3 [1–7] on the last examination. Fifty-five percent of lesions involved the cervical levels. Secondary progressive evolution occurred in 3 of 18 (17%) patients.DiscussionPure spinal MS could be a rare entity in the MS disease spectrum. However, the existence of a distinct entity in the inflammatory CNS disorders cannot be excluded.

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