qRT–PCR of postmortem hippocampal brain tissue from non-demented controls or patients with AD (Fig. 3f and Supplementary Data Table 1) corroborated the mouse and human data: irrespective of AD pathology, we found IL12RB2 transcripts specific for the IL-12 receptor to be expressed in human brains, whereas transcripts for the IL-23 receptor were lacking. Here, IL23R is linked to Alzheimer disease.