Abstract General Information

Title

Low seropositive John Cunningham virus (JCV) profile in a Northeast Brazilian Natalizumab MS treated population: differences comparing with global data.

Abstract

Introduction: Natalizumab (NTZ) is one of the most used high efficacy treatments for people with multiple sclerosis (pwMS) around the world. However, it cannot be used without risks. The John Cunningham virus (JCV), usually harmless, can lead to progressive multifocal leukoencephalopathy (PML) and a risk stratification based on JCV serology is mandatory. Data regarding Brazilian population, especially low prevalence areas, are still scarce.
Objectives: To evaluate the serological profile of JCV in pwMS patients under NTZ treatment in a northeast Brazilian MS center.
Methods: Patients under NTZ treatment between July 2010 and March 2023 were included. JCV serology data was collected at the beginning of Natalizumab treatment, at 12 infusions and 24 infusions follow-up.
Results: From 108 patients enrolled, 68 (63%) had an initial negative serology and 40 (37%) positive. Median follow-up time was of 15 months (IQR 8-24). Considering seronegative patients who had more than one JCV test (40), seroconversion occurred in 6 cases over an average period of two years, representing a 15% seroconversion rate. 2 patients were found to be negative after an initial positive result during follow-up. From 40 JCV seropositive patients, median value was of 1.54 (IQR 0.86-2.80) in the first test, 1.18 (IQR 0.55-1.99) in 12 infusion follow-up and 1.47 (IQR 0.68-2.53) in the 24-infusion follow-up. There were no cases of PML reported in the studied population.
Conclusion: The prevalence of JCV-seropositive patients (35%) in our population under NTZ treatment was lower compared to similar published studies (51.2%) and a higher seroconversion rate (15%) was found in parallel to general JCV seroconversion data in MS (10.8%). Although the result differs from global numbers, more robust research is needed to reaffirm the findings.