MS patients treated with natalizumab have a positive serology response to SARS-CoV-2 S1/S2 following vaccination with two doses of mRNA COVID-19 vaccine

Introduction: Natalizumab is an immunomodulatory drug approved for the treatment of multiple sclerosis. Natalizumab binds to α4β1-integrin and blocks its interaction with VCAM-1. As a result, leukocyte migration into brain tissue is inhibited, reducing inflammation and preventing the formation of lesions. Aims: The aim of this study, is to investigate the influence of natalizumab on antibody response in Multiple Sclerosis patients immunized with 2 doses of mRNA COVID-19 vaccine(pfizer). Methods: Sixty-two Multiple sclerosis patients receiving natalizumab (n=20), Interferon beta-1a (n=11), dimethyl fumarate (n=9) or no therapy (n=22) were compared with 37 healthy controls. All subjects received 2 doses of mRNA COVID-19 vaccine(pfizer). Serum samples were collected pre-vaccination and 2-6 weeks after second dose. Serology response to spike protein of COVID-19 was measured using Liaison SARS-CoV-2 S1/ S2 IgG assay. Results: All participants at the study had a positive serology response to COVID-19 spike protein. No significant differences were found in serology response for MS patients treated with Natalizumab (276.5 AU/mL ± 96.73), Interferon beta-1a (257.9 AU/mL ± 93.48), Tecfidera (254.3 AU/mL ± 109.2), or untreated (257.9 AU/mL ± 93.48), and HCs (277.4 AU/mL ± 100.9). There is a significant negative correlation between IgG titer and duration of natalizumab therapy (r=-0.56, p=0.01). Conclusion: We found that all MS patients treated with natalizumab had positive serology response to COVID-19 spike protein 2-4 weeks after vaccination with 2 doses of mRNA COVID-19 vaccine. Although all patient treated with natalizumab had protective vaccine-specific antibodies following two doses of mRNA COVID-19 vaccine, we found a significant negative correlation between IgG titer and time since starting natalizumab therapy. It is possible that an accumulate effect of a long period treatment with natalizumab, partly prevent entry of antigen-presenting cells such as dendritic and macrophages into the muscle and therefore the immune response to vaccine is slightly reduced.