The cerebrospinal fluid (CSF) of patients with relapsing-remitting MS has CCR2+CCR5+ TH1 cells during a relapse; CCR5+CD8+ T cells and CCR5+ monocytes are higher in the CSF than in the blood of patients with the disease, and CCR5 is expressed in inflammatory cells infiltrating the CNS in vivo (17, 18). The gene discussed is CCR5; the disease is relapsing-remitting multiple sclerosis.