Cytomegalovirus Seropositivity and Its Impact on Clinical Progression of Multiple Sclerosis: A Case-Control Study from Northeastern Iran

Backgrounds: Investigating the role of cytomegalovirus (CMV) in multiple sclerosis (MS) could clarify its potential impacts on the disease progression and pathogenesis. This study aimed to examine the relationship between CMV seropositivity and MS development as well as its impact on the disease clinical course and patients' disability status in North Khorasan province. Materials & Methods: This case-control study assessed 98 MS patients and 100 age- and sex-matched healthy controls using the 2017 McDonald diagnostic criteria. Disability levels were evaluated via the Expanded Disability Status Scale (EDSS). The presence and levels of anti-CMV IgG and IgM antibodies in serum samples of both groups were quantified by ELISA.Findings: All MS patients were seropositive for anti-CMV IgG and seronegative for anti-CMV IgM, akin to healthy controls. Interestingly, MS patients exhibited significantly lower serum anti-CMV IgG levels compared to healthy individuals (178.7 ± 61.92 vs. 342.9 ± 3.121, p< .0001). Ethnicity and EDSS scores influenced anti-CMV IgG levels, with higher EDSS scores correlated with lower serum levels. In patients with relapsing-remitting multiple sclerosis (RRMS), serum levels of anti-CMV IgG exhibited significant variations based on age, EDSS scores, and the disease duration.Conclusion: This study reveals a complex link between CMV infection and MS. While anti-CMV IgG antibodies were found in both MS patients and healthy individuals, lower levels in MS patients might suggest a protective effect against MS progression. Additionally, reduced anti-CMV IgG levels correlated with higher EDSS scores, indicating that diminished CMV-specific immunity could worsen disease severity, especially in RRMS patients.