Frequency and clinical correlates of brain gadolinium deposition in patients with Multiple Sclerosis

Multiple sclerosis (MS) is a chronic neuroinflammatory disease of the central nervous system (CNS)representing a common cause of neurological disability in your people. While the relapsing-remittingphenotype is the most frequent form at disease onset, many patients experience an unrelentingdisability progression over time.To date, many disease modifying treatments (DMTs) are available to counteract disease activity evenif the finding of an effective drug on progressive MS forms is still an unmet need. Several studiesshowed that the early initiation of high effective DMT is the best treatment strategy of MS. Whilstthe achievement of the highest anti-inflammatory effect is the mainstream of neurologists andresearchers, it is worth noting that greater is the efficacy of that DMT and greater is the risk of causingrelated adverse events. For this reason, many DMTs require focused and rigorous surveillance.Natalizumab (NTZ) is a high effective DMTs for the treatment of MS. Since 2006, when it has beencommercialized, it changed the natural history of MS becoming one of the most prescribed DMTworldwide. NTZ inhibits the extravasation of peripheral lymphocytes into CNS limiting theintrathecal inflammation. If this mechanism of action lead to the reduction of MS activity, on theother hand, it exposes patients to higher risk of opportunistic CNS infections, especially progressivemultifocal leukoencephalopathy (PML) caused by the intrathecal reactivation of John Cunninghamvirus (JCV).The brain MRI monitoring strategy in patients with MS is vastly different worldwide ranging fromone MRI scans every 6 months to one year. It is worth noting that the MRI monitoring strategy gainseven more relevance in patients under treatment with NTZ to detect the early appearance of PMLpathological changes. In this case, the monitoring range is highly variable across different MS clinicsdepending mainly by serum JCV status and treatment duration. Of note, before the recommendationsof the 2021 MAGNIMS consensus, the administration of gadolinium was routinely employed inpatients with MS.The aim of this study is to explore the effect of recurrent gadolinium exposition in patients with MStreated with NTZ who routinely underwent brain MRI scan for the PML-risk surveillance purpose