IFNG and periodontitis: 13 In this regard, an increase in mRNA and IFN-γ protein has been reported in gingival tissue, gingival crevicular fluid (GCF), and serum samples from CP patients compared to healthy subjects (HS). 14-19 Regarding the expression of IFN-γR in CP, only studies of IFN- γR1 polymorphisms exist and no association has been found for periodontitis. 20,21 Therefore, the objective of this study was to evaluate IFN-γ levels and the expression of IFN-γR in gingival tissue samples from CP patients compared to healthy subjects.