IFNG and Alzheimer disease: In addition, the anaphylatoxin C5a receptor is increased in AD mice, and treatment with a C5aR antagonist decreased IL-4 and IFN-γ levels in skin tissue, as well as the levels of IL-4, IFN-γ, histamine, and IgE in the serum, indicating that blocking C5aR can inhibit AD [10].