While ADM2 was upregulated in periodontitis in the diabetic and non-diabetic patients (S4 Table), GPR182, CALCRL (validated at the protein level), and RAMP2 were significantly upregulated in the diabetic patients only, suggesting that ADM may perform its biological functions mainly in T2DM-related periodontitis. This evidence concerns the gene ACKR5 and type 2 diabetes mellitus.