Ozakbas, SerkanAlizada, SaidCevik, SumeyyeSamadzade, UlviYapici, Nurbanu AygunduzZengin, Ela SimayCaliskan, Can2025-11-252025-11-2520252211-03482211-0356https://doi.org/10.1016/j.msard.2025.106813https://hdl.handle.net/20.500.14365/6614Objective: To investigate the long-term prognostic significance of cerebrospinal fluid oligoclonal band (OCB) positivity and its subtypes (Type 2 and Type 3) in patients with relapsing-remitting multiple sclerosis (RRMS). Methods: This retrospective cohort included 2324 RRMS patients diagnosed using the 2017 McDonald criteria. All patients had documented OCB status and at least 2 years of clinical follow-up; a subset had 5-year data. Outcomes included Expanded Disability Status Scale (EDSS), annualised relapse rate (ARR), and conversion to secondary progressive MS (SPMS). Subgroup analysis compared Type 2 and Type 3 OCBpositive patients. Results: OCB positivity was observed in 82.4 % of patients. At year 2, no significant differences in EDSS, ARR, or SPMS conversion were found between OCB-positive and OCB-negative groups. However, by year 5, the OCBpositive group had a significantly higher rate of conversion to SPMS (p < 0.05). Subgroup analysis showed that Type 3 OCB patients had significantly lower EDSS scores at year 2 compared to Type 2 (p < 0.05), but this difference disappeared at year 5. Conclusion: OCB positivity may be associated with a higher risk of progression to SPMS over the long term. Type 3 OCB may indicate a milder early disease course, although its protective effect diminishes over time. Incorporating OCB subtype analysis into RRMS prognosis may enhance early risk stratification.eninfo:eu-repo/semantics/closedAccessRelapsing-Remitting Multiple SclerosisOligoclonal BandsCerebrospinal FluidPrognostic BiomarkersSecondary Progressive MSArticle10.1016/j.msard.2025.1068132-s2.0-105019946738