Delayed treatment of MS is associated with high CSF levels of IL-6 and IL-8 and worse future disease course

Clinical deterioration of relapsing–remitting MS (RR-MS) patients reflects not only the number and severity of overt inflammatory and demyelinating episodes, but also subtle central damage caused by persistent exposure to inflammatory molecules. To explore the correlation between levels of CSF inflammatory molecules at the time of diagnosis and both demographic and clinical characteristics of a large sample of RR-MS patients, as well as the predictive value of cytokine levels on their prospective disease course. In 205 patients diagnosed with RR-MS, we measured at the time of diagnosis the CSF levels of inflammatory molecules. Clinical and MRI evaluation was collected at the time of CSF withdrawal and during a median follow-up of 3 years. The time interval between the first anamnestic episode of focal neurological dysfunction and RR-MS diagnosis was the main factor associated with high CSF levels of IL-6 and IL-8. Furthermore, elevated CSF levels of these cytokines correlated with enhanced risk of clinical and radiological disease reactivation, switch to second-line treatments, and with disability progression in the follow-up. Delayed diagnosis and treatment initiation are associated with higher CSF levels of IL-6 and IL-8 in RR-MS, leading to worsening disease course and poor response to treatments.