Diagnosis; Objective RespOnse; THErApy

"A lumbar puncture (spinal tap) is performed in patient lower back, in the lumbar region.~During a lumbar puncture, a needle is inserted between two lumbar bones (vertebrae) to remove a sample of cerebrospinal fluid (CSF). This is the fluid that surrounds brain and spinal cord to protect them from injury.~This procedure is usually performed at the time of diagnosis for disease staging and/or repeated in the course of the disease history, only if positive or for clinical reasons (i.e. suspicious of relapse progression).~In this study sequential CSF and peripheral blood samples of study population will be collected also at different time points, with the aim to improve diagnostics sensitivity, response assessment and monitoring early CNS relapse."