IL6 and Alzheimer disease: While CNS-derived soluble immune factors including pro-inflammatory cytokines like IL-1β, TNFα and IL-6 have been studied intensely [10, 11, 21, 23, 29, 52, 55], their role in AD is still a matter of debate, also due to the fact that the respective results - at least for some of the analyzed cytokines - is not always consistent [43].