IL6 and Classical progressive supranuclear palsy: Some data indicate the existence of significant differences between concentrations of interleukin 1β (IL1β) and interleukin 6 (IL6) in serum and cerebrospinal fluid (CSF) among patients with PSP–Richardson’s syndrome (PSP-RS) and PSP–Parkinsonism predominant (PSP-P), with the lowest concentrations of interleukins observed among the PSP-RS group [13].