Background: Vaccine-elicited adaptive immunity is a prerequisite for control of SARS-CoV-2 infection. Multiple sclerosis (MS) disease-modifying therapies (DMTs) differentially target humoral and cellular immunity. A comprehensive comparison of MS DMTs on SARS-CoV-2 vaccine-specific immunity is needed, including quantitative and functional B and T cell responses.Methods: Spike-specific antibody and T cell responses were measured before and following SARS-CoV-2 vaccination in a cohort of 80 subjects, including healthy controls and MS patients in six DMT groups: untreated, glatiramer acetate (GA), dimethyl fumarate (DMF), natalizumab (NTZ), sphingosine-1-phosphate (S1P) receptor modulators, and anti-CD20 monoclonal antibodies. Anti-spike antibody responses were quantified by Luminex assay, high-resolution spike epitope reactivity was mapped by VirScan, and pseudovirus neutralization was assessed.Spike-specific CD4+ and CD8+ T cell responses were characterized by activation-induced marker (AIM) expression, cytokine production, and tetramer analysis.Results: Anti-spike IgG levels were similar between healthy controls, untreated MS, GA, DMF, and NTZ patients, but were significantly reduced in anti-CD20 and S1P-treated patients. Antispike seropositivity in anti-CD20 patients was significantly correlated with CD19+ B cell levels and inversely correlated with cumulative treatment duration. Spike epitope reactivity and pseudovirus neutralization was reduced in anti-CD20 and S1P patients, directly correlating with reduced spike receptor binding domain (RBD) IgG levels. Spike-specific CD4+ and CD8+ T cell reactivity remained robust across all groups except in S1P-treated patients in whom post-vaccine CD4+ T cell responses were attenuated.Conclusions: These findings from a large MS cohort exposed to a wide spectrum of MS immunotherapies have important implications for treatment-specific COVID-19 clinical guidelines.

Vaccine-elicited adaptive immunity is an essential prerequisite for effective prevention and control of coronavirus 19 (COVID-19). Treatment of multiple sclerosis (MS) involves a diverse array of disease-modifying therapies (DMTs) that target antibody and cell-mediated immunity, yet a comprehensive understanding of how MS DMTs impact SARS-CoV-2 vaccine responses is lacking. We completed a detailed analysis of SARS-CoV-2 vaccine-elicited spike antigen-specific IgG and T cell responses in a cohort of healthy controls and MS participants in six different treatment categories. Two specific DMT types, sphingosine-1-phosphate (S1P) receptor modulators and anti-CD20 monoclonal antibodies (mAb), resulted in significantly reduced spike-specific IgG responses. Longer duration of anti-CD20 mAb treatment prior to SARS-CoV-2 vaccination were associated with absent antibody responses. Except for reduced CD4+ T cell responses in S1P-treated patients, spike-specific CD4+ and CD8+ T cell reactivity remained robust across all MS treatment types. These findings have important implications for clinical practice guidelines and vaccination recommendations in MS patients and other immunosuppressed populations.

ObjectiveTo determine the transfer of rituximab, an anti-CD20 monoclonal antibody widely used for neurologic conditions, into mature breast milk.MethodsBreast milk samples were collected from 9 women with MS who received rituximab 500 or 1,000 mg intravenous once or twice while breastfeeding from November 2017 to April 2019. Serial breast milk samples were collected before infusion and at 8 hours, 24 hours, 7 days, and 18–21 days after rituximab infusion in 4 patients. Five additional patients provided 1–2 samples at various times after rituximab infusion.ResultsThe median average rituximab concentration in mature breast milk was low at 0.063 μg/mL (range 0.046–0.097) in the 4 patients with serial breast milk collection, with an estimated median absolute infant dose of 0.0094 mg/kg/d and a relative infant dose (RID) of 0.08% (range 0.06%–0.10%). Most patients had a maximum concentration at 1–7 days after infusion. The maximum concentration occurred in a woman with a single breast milk sample and was 0.29 μg/mL at 11 days postinfusion, which corresponds with an estimated RID of 0.33%. Rituximab concentration in milk was virtually undetectable by 90 days postinfusion.ConclusionsWe determined minimal transfer of rituximab into mature breast milk. The RID for rituximab was less than 0.4% and well below theoretically acceptable levels of less than 10%. Low oral bioavailability would probably also limit the absorption of rituximab by the newborn. In women with serious autoimmune neurologic conditions, monoclonal antibody therapy may afford an acceptable benefit to risk ratio, supporting both maternal treatment and breastfeeding.

ObjectiveTo evaluate radiologic and clinical inflammatory activity in women with MS during pregnancy and postpartum.MethodsWe performed a retrospective analysis of prospectively collected clinical and MRI reports for women who became pregnant while followed at the University of California, San Francisco MS Center between 2005 and 2018. Proportion of brain MRIs with new T2-hyperintense or gadolinium enhancing (Gd+) lesions (primary outcome) and annualized relapse rate (ARR; secondary) were compared before and after pregnancy.ResultsWe identified 155 pregnancies in 119 women (median Expanded Disability Status Scale [EDSS] 2.0). For the 146 live birth pregnancies, prepregnancy ARR was 0.33; ARR decreased during pregnancy, particularly the third trimester (ARR 0.10, p = 0.017) and increased in the 3 months postpartum (ARR 0.61, p = 0.012); and 16% of women experienced a clinically meaningful increase in EDSS. Among 70 pregnancies with paired brain MRIs available, 53% had new T2 and/or Gd+ lesions postpartum compared with 32% prepregnancy (p < 0.001). Postpartum clinical relapses were associated with Gd+ lesions (p < 0.001). However, even for patients without postpartum relapses, surveillance brain MRIs revealed new T2 and/or Gd+ lesions in 31%. Protective effects of exclusive breastfeeding for ≥3 months (odds ratio = 0.3, 95% confidence interval 0.1–0.9) were observed for relapses.ConclusionsBuilding on previous reports of increased relapse rate in the first 3 months postpartum, we report a significant association between inflammation on MRI and this clinical activity. We also detected postpartum radiologic activity in the absence of relapses. Both clinical and radiologic reassessment may inform optimal treatment decision-making during the high-risk early postpartum period.