Recently, antibodies against the inward rectifying potassium channel KIR4.1 were reported to be present in 47% of adult patients with MS and CIS and in an even higher proportion of pediatric patients, but in no healthy controls, using an enzyme-linked immunosorbent assay (ELISA) with either full-length KIR4.1 protein or peptide (amino acids 83–120) [98,99]. This evidence concerns the gene KCNJ10 and myeloid sarcoma.