Different HLA genotype pattern in patients with Multiple Sclerosis onset after COVID-19 vaccine.

Abstract

Abstract Background: Few cases of Multiple Sclerosis (MS) onset after COVID-19 vaccination have been reported, even though the evidence is insufficient to establish causality. The aim of this study is to compare cases of newly diagnosed MS before and after the outbreak of COVID-19 pandemic and the impact of COVID-19 vaccination. Potential environmental and genetic predisposing factors were also investigated, as well as clinical patterns. Methods: This is a single-centre retrospective cohort study including all patients who presented with MS onset between January 2018 and July 2022. Data on COVID-19 vaccination administration, dose, and type were collected. HLA-DRB1 genotyping was performed in three subgroups. Results: 266 patients received a new diagnosis of MS in our centre, 143 before the COVID-19 pandemic (until and including March 2020) and 123 during COVID-19 era (from April 2020). The mean number of new MS onset per year was not different before and during COVID-19 era, as well as baseline patients’ characteristics, type of onset, clinical recovery, and radiological patterns. Fourteen (11.4%) patients who subsequently received a new diagnosis of MS had a history of COVID-19 vaccination within one month before symptoms onset. Patients’ characteristics, type of onset, clinical recovery, and radiological patterns do not differ from those of patients with non-vaccine-related new diagnosis of MS. The allele frequencies of HLA-DRB1*15 were 17.6% and 22.2% in patients with not-vaccine-related disease onset before and during COVID-19 era respectively, while no case of HLA-DRB1*15 was identified among patients with a new diagnosis of MS post-COVID-19 vaccine. In contrast HLA-DRB1*08+ or HLA-DRB1*10+ MS patients were present only in this subgroup. Conclusions: Although a causal link between COVID-19 vaccination and MS cannot be detected, it is interesting to note and speculate about the peculiarities and heterogeneities underlying disease mechanisms of MS, where the interactions of genetic and environment could be crucial also for the follow up and the evaluation of therapeutic options.