The cytokine-signature in Multiple Sclerosis. A study during SARS-Cov-2 pandemic

Marco Puthenparampil^1,2,3*Annachiara Marin^3,4Federica De Napoli¹Alessandro Di Paola⁵Annamaria Valentina Mauceri¹Susanna Ruggero¹Francesca Rinaldi⁶Paola Perini⁶Antonella Viola^3,4BARBARA MOLON^3,4Paolo Gallo^1,6

• ¹Department of Neuroscience, School of Medicine and Surgery, University of Padua, Padua, Italy
• ²Multiple Sclerosis Centre, Azienda Ospedaliera di Padova, Padua, Italy, Padova, Italy
• ³Immune-Mediated Nervous System Disease Study Group, Fondazione Istituto di Ricerca Pediatrica Città della Speranza, Padova, Italy, Padova, Italy
• ⁴Universita degli Studi di Padova Dipartimento di Scienze Biomediche, Padua, Italy
• ⁵Azienda Ospedale Universita Padova Unita Operativa Complessa di Neuroradiologia, Padua, Italy
• ⁶Multiple Sclerosis Centre, Azienda Ospedaliera di Padova, Padova, Italy

Background. Multiple sclerosis (MS) is a multifactorial autoimmune disorder resulting from the interplay of genetic susceptibility and environmental exposures. Viral infections, particularly Epstein–Barr virus (EBV), have been implicated in disease pathogenesis through mechanisms such as molecular mimicry. The SARS-CoV-2 pandemic provided a unique opportunity to explore whether large-scale viral exposure influenced early MS immunopathogenesis. Methods. In this cross-sectional study, we compared cytokine profiles in patients with first MS onset during 2020 (pandMS, n=36) with age-, sex-, and disease-duration matched pre-pandemic MS cases (MS, n=20) and a reference cohort of individuals with other non-inflammatory neurological diseases (ONIND, n=20). Paired cerebrospinal fluid (CSF) and serum samples were analysed for 45 cytokines, along with neurofilament light chain (NfL), BAFF, and CXCL13. Intrathecal cytokine synthesis was estimated using CSF/serum quotients and indices. MRI and clinical evaluations, including Expanded Disability Status Scale (EDSS), were conducted in a patient subset. Statistical analyses included correlation, logistic regression, and multivariate modelling. Results. CXCL13 and BAFF were elevated in both MS and pandMS, consistent with B-cell recruitment and survival. A second cytokine cluster (marked by CCL4) indicative of astrocyte–microglia activation increased exclusively in MS. In pandMS, peripheral IL-7, PDGF-BB, and CCL2 were selectively elevated. Notably, serum and CSF CCL2 correlated only in pandMS, and serum CCL2 associated with white-matter lesion burden. Logistic regression distinguished pandMS from MS based on CXCL13 index, CCL4 index, and serum PDGF-BB (r² = 0.65). MRI lesion counts and clinical parameters did not differ between groups. Conclusions. While core MS-associated cytokines remain temporally stable, the pandemic period was associated with a shift toward peripheral immune activation at disease onset in pandMS. These findings likely reflect environmental and behavioural changes during the SARS-CoV-2 pandemic rather than direct viral effects. Our results highlight the dynamic interplay between central and peripheral immune mechanisms in early MS and reinforce the potential role of environmental exposures in modulating disease immunopathogenesis.