Characterization of humoral response to COVID mRNA vaccines in multiple sclerosis patients on disease modifying therapies

Little is known about COVID-19 mRNA vaccine humoral immune responses in patients with central nervous system autoimmune demyelinating diseases, multiple sclerosis (MS) and neuromyelitis optica (NMO), who are on B-cell depleting therapies (BCDT) and other disease modifying therapies (DMTs). We conducted a single center prospective study to identify the clinical and immunological features associated with vaccine-induced antibody response in 53 participants before and after COVID-19 mRNA vaccination. This is the first report on the anti-spike RBD and anti-nucleocapsid antibody response, along with pre- and post-vaccine absolute lymphocyte counts (ALC) and flow cytometry analysis of CD19 and CD20 lymphocytes in patients with MS and NMO. We tested the hypothesis that patients on BCDT may have impaired COVID-19 vaccine humoral responses. Among patients on BCDT, 36.4% demonstrated a positive antibody response to spike RBD, in comparison to 100% in all other groups such as healthy controls, untreated MS, and patients on non-B cell depleting DMTs (p < 0.0001). Immunological data revealed lower baseline (pre-vaccination) levels of IgM in patients on BCDT (p = 0.003). Low CD19 and CD20 counts and a shorter interval from the last B cell depleting therapy infusion to the first vaccine dose were associated with a negative spike RBD antibody response (non-seroconverter) in patients on BCDT. Age, body mass index (BMI) and total treatment duration did not differ between seroconverters and non-seroconverters.