AD displays a characteristic increase in IL-1Ra (not observed in other conditions), in sIL-1R1 (observed in IgG4-related diseases), in sIL-1R3 (as in SMC), in IL-18BP (observed in other diseases, but not in SMC or MCI that show a decrease), and in sIL-1R4. The gene discussed is IL1R1; the disease is Alzheimer disease.