An IL-5 Single-Nucleotide Polymorphism Influences Neuroinflammation and Prospective Disease Activity in Multiple Sclerosis

(1) Multiple sclerosis (MS) is identified by a complex interaction between central inflammation and neurodegeneration. Genetic individual variability could play a significative role in clinical presentation. The interleukin-5 (IL-5) rs2069812 single-nucleotide polymorphism (SNP) seems to define the clinical course of Th2 autoimmune diseases, while its role in MS has never been investigated. (2) In a group of 230 patients diagnosed with relapsing-remitting MS (RR-MS) or progressive MS (P-MS) and controls (IC), rs2069812 polymorphism, cerebrospinal fluid (CSF) levels of inflammatory mediators, and clinical and demographic characteristics were determined. In RR-MS patients, No Evidence of Disease Activity (NEDA-3) at three years of follow-up was detected. (3) We identified higher levels of proinflammatory cytokines, particularly IL-2 (median [IQR], RR-MS = 0.2 [0-0.7]; P-MS = 0.1 [0-1.6]; IC = 0.1 [0.0-0.1];