Lymphocyte profiles after a first demyelinating event suggestive of multiple sclerosis reveal early monocyte and B cell alterations

INTRODUCTION: Often, an isolated clinical event suggestive of CNS demyelination confers a risk of conversion to multiple sclerosis. In this study, we investigate lymphocyte profiles after a first clinical event suggestive of multiple sclerosis (MS), which could contribute to the current understanding of early inflammatory responses in this demyelinating disease. METHODS: Twenty treatment-naïve clinically isolated syndrome (CIS) patients and fifteen healthy participants were included in our assessment of lymphocyte profiles and B cell subsets using multicolour flow cytometry. Analysis was made at 3-6 months (Baseline), 12, and 24 months after a first clinical event. We also performed a sub-analysis of patients that received glatiramer acetate (GLAT) after their baseline visit up to 24 months after the first clinical event. RESULTS: Our analysis revealed monocyte and B cell differences between groups. Percentages of CD19+CD20+ B cells were lower in CIS patients compared to healthy individuals at baseline. Additionally, monocyte distribution among groups was different. A subgroup analysis of patients treated with GLAT (n= 10) showed an increased percentage of naïve (p<0.05) and memory pre-switched (p<0.01) B cells up to 24 months after their baseline visit compared to the untreated group (n= 10). CONCLUSION: Our results showed early monocyte and B cell subsets alterations in pwCIS. Moreover, GLAT-treated patients showed an increased percentage of naïve and memory pre-switched B cells after 24 months of treatment. Further research is needed to elucidate the role of B cells and monocyte disturbances during inflammatory processes after a first clinically-MS suggestive event.