IRF7 and Alzheimer disease: The majority of AD brains showed decreased hippocampus mRNA levels of IRF7 (n = 28), MED23 (n = 20), IL28B (n = 21), and IFN-α (n = 19), whilst a small AD group had increased mRNA levels of MED23 (n = 11), IL28B (n = 12), and IFN-α (n = 9).