Neuroaxonal damage in natalizumab-treated MS patients: The role of JCV antibody titres

Background: While John Cunningham virus (JCV) is known to cause neuronal damage in progressive multifocal leukoencephalopathy (PML) among natalizumab-treated MS patients, its association with axonal loss in non-PML conditions remains unclear. Methods: In a cohort of 128 natalizumab-treated MS patients, serum neurofilament (sNfL) levels and JCV antibody titres were measured. Results: Among 128 patients (mean age = 38.4 years, 71.9% female), 51 (40%) were JCV positive. NfL levels increased by 15.3% for JCV index <0.7 (95% confidence interval [CI] = 0.963–1.381), by 18.6% for index 0.7–1.5 (95% CI = 1.009–1.394) and by 21.1% for index >1.5 (95% CI = 1.040–1.409) compared to JCV negative patients. Conclusion: These findings indicate a potential link between JCV burden and neuroaxonal degeneration in natalizumab-treated MS patients.