IGHG3 and periodontitis: In subjects with DL plus periodontitis versus HS, three DEG were confirmed (DAB2, CD47, and HLADRB4), and in the comparison between subjects with periodontitis alone versus HS: the IGHG3 gen (IGHDL-P) was upregulated, and the ITGB2 and HLADRB4 genes were downregulated.