JCV serology in time: 3 years of follow-up.

OBJECTIVES: Although many neurologists are reluctant to use natalizumab in MS (multiple sclerosis) given the increased risk for PML (progressive multifocal leukoencephalopathy), trust was regained with the introduction of JCV antibody titres as a potent disease-modifying therapy. Literature shows that in patients with a negative JCV serology, the risk of PML is virtually non-existent. Unfortunately, seroconversion causes concern amongst many neurologists. Furthermore, when patients seroconvert, it is still unclear what the risk is of passing the important threshold of 1.5. MATERIALS & METHODS: JCV serology data of 161 patients were analysed, upon treatment with natalizumab at the University Hospital in Lille, France, between May 2012 and November 2014. RESULTS: Of the 81 patients who tested negative for JCV antibody at baseline, 23 (28.3%) seroconverted but only seven (8.6%) passed the threshold of 1.5. Of the 80 patients testing positive for JCV antibody at baseline, eight had an initial JCV antibody titre of 0.9 or lower of which only one of eight (12.5%) patients passed the threshold of 1.5 in the following 3 years. Eight of 15 (53.3%) patients passed this threshold if the initial serology was higher than 0.9. CONCLUSIONS: JCV-negative patients and JCV-positive patients with antibody levels below or equal to 0.9 both have a low risk of surpassing the 1.5 threshold.

Two cases of relapses in primary progressive multiple sclerosis after fingolimod withdrawal.

We report two cases of primary progressive multiple sclerosis (PPMS) included in the INFORMS cohort, experiencing a relapse related to a single MRI gadolinium-enhancing lesion 3 months after fingolimod withdrawal. These two patients share similarities with relapsing-remitting multiple sclerosis cases described in the same situation, suggesting that the initiating process of the active demyelinating plaques is also present in PPMS, even without relapses, but may be triggered as fingolimod is withdrawn. Although the results of the INFORMS study suggest that fingolimod may not slow down the progression, some PPMS patients might still benefit from a disease-modifying treatment.