o:26024 Humoral response to SARS-CoV-2 COVID-19 vaccines in patients with multiple sclerosis treated with immune reconstitution therapies en ABSTRACT Background: It has been generally accepted that people with MS (PwMS) should be vaccinated against COVID-19. The aim of our investigation was to evaluate the humoral response to natural SARS-CoV-2 infection and to two COVID-19 vaccines (BNT162b2 Pfizer-BioNTech and Beijing/Sinopharm BBIBP-CorV) in our cohort of PwMS under high efficacy disease modifying therapies (DMTs), cladribine and alemtuzumab. Methods: Twenty two PwMS treated at the Clinic of Neurology, in Belgrade, who developed COVID-19 and/or were vaccinated against SARS-CoV-2, during treatment with cladribine and alemtuzumab, were included. Out of 18 patients treated with cladribine, 11 developed COVID-19, and 11 were vaccinated against SARS-CoV-2 (four with mRNA vaccine, 7 with Sinopharm). Four MS patients under alemtuzumab were vaccinated against SARS-CoV-2; three with mRNA, and one with Sinopharm vaccine. SARS-Cov-2 IgG response was measured using ELISA anti- spike protein-based serology (INEP, Belgrade, Serbia). Results: All 7 patients under cladribine treatment who suffered from COVID-19, developed IgG antibodies, 2.0-5.5 months after last symptoms. All four (100%) patients under cladribine who were vaccinated with Pfizer-BioNTech vaccine, and three out of seven (42.9%) vaccinated with Sinopharm, developed antibodies. All 4 patients under alemtuzumab developed antibodies after vaccination. In all cases, seroprotection occurred, irrespective of timing of vaccination and absolute lymphocyte count. Conclusion: Our findings in a small number of highly active PwMS in whom, lymphodepleting, immune reconstitution therapies, were applied in order to successfully manage MS, indicate that in a number of these patients it was possible to develop at the same time seroprotection in these patients after COVID-19 vaccination in these complex circumstances. COVID-19, Pfizer-BioNTech, Sinopharm, alemtuzumab, cladribine, humoral response, multiple sclerosis, vaccination 1552099 10.1016/j.msard.2021.103150 2022-06-12T18:10:56.776Z 44 yes 46 Jelena Drulović University of Belgrade, Faculty of Medicine, Clinic of Neurology, University Clinical Center of Serbia, Serbia Tatjana Pekmezović University of Belgrade, Faculty of Medicine, Institute of Epidemiology, Serbia person Šarlota Mesaroš University of Belgrade, Faculty of Medicine, Clinic of Neurology, University Clinical Center of Serbia, Serbia person Marija Gnjatović University of Belgrade, Institute for the Application of Nuclear Energy INEP, Serbia doktor biotehničkih nauka person 0000-0001-8233-1636 Danica Ćujić University of Belgrade, Institute for the Application of Nuclear Energy INEP, Serbia doktor medicinskih nauka-farmacija person 0000-0002-6145-3850 Nikola Veselinović University of Belgrade, Faculty of Medicine, Clinic of Neurology, University Clinical Center of Serbia, Serbia person Olivera Tamas University of Belgrade, Faculty of Medicine, Clinic of Neurology, University Clinical Center of Serbia, Serbia person Vanja Martinović Clinic of Neurology, University Clinical Center of Serbia, Serbia person Jovana Ivanović Clinic of Neurology, University Clinical Center of Serbia, Serbia person application/pdf 656697 https://phaidrabg.bg.ac.rs/o:26024 no yes 18 70 92000001 11A32 11A3250 11A29 11A2901 11A29 11A2904 11A32 11A3231 Multiple Sclerosis and Related Disorders 54 Elsevier 2021