Profile of Cytokines Associated with SARS-CoV2 Seropositivity in Multiple Sclerosis Patients and Its Persistence over Six Months

<b>Background:</b> Patients with multiple sclerosis (pwMS) receiving disease-modifying therapies (DMTs) may exhibit altered immune responses to infections such as SARS-CoV-2. This study aimed to characterize the cytokine profiles associated with prior SARS-CoV-2 infection and to identify immune markers related to the persistence of the humoral response in pwMS. <b>Methods:</b> A total of 90 pwMS were recruited before the introduction of COVID-19 vaccination in Spain; 46 were seropositive-defined by the presence of IgG, IgM, or IgA antibodies against SARS-CoV-2-and 44 were seronegative. We compared baseline cytokine levels between groups and followed seropositive individuals for six months to assess IgG antibody persistence. <b>Results:</b> Seropositive patients showed significantly lower baseline levels of IL-10, IL-23, and IFN-α compared to seronegative individuals. Notably, elevated IL-18 at baseline was associated with persistent IgG seropositivity at six months. <b>Conclusions:</b> These findings suggest a distinct cytokine profile in SARS-CoV-2-exposed pwMS and highlight IL-18 as a potential marker of sustained humoral response. This study provides insight into host-virus immune dynamics in MS patients and may help guide future strategies for infection monitoring and immune evaluation in this population.