Interferon-Gamma (IFNg) +874A/T Polymorphism Does Not Significantly Affect the Severity of Periodontitis

Interferon-gamma (IFNg) is an immune-regulatory cytokine with a role in host responses to periodontitis. Genetic factors have been reported to modify the corresponding protein expression. The objective of this study was to evaluate the association and role of IFNg polymorphisms, such as IFNg +874 A/T, and the susceptibility to periodontitis.

A total of 100 unrelated subjects were included in the present study. Genomic deoxyribonucleic acid (DNA) was obtained from peripheral blood of 43 patients with mild periodontitis and 57 patients with severe periodontitis. The determined clinical parameters of periodontitis included probing depth, clinical attachment loss, and papilla bleeding index. The oral hygiene indicators were also assessed. The level of IFNg was determined from the gingival crevicular fluid by enzyme-linked immunosorbent assay technique. The IFNg +874 A/T polymorphisms were analyzed from peripheral blood by the method of restriction fragment length polymorphism-polymerase chain reaction.

Statistical analysis of the results was conducted using chi-squared testing for categorical data. Independent t-tests and Mann-Whitney U tests were used for numeric data. Kruskal-Wallis testing was used to compare genotypes concerning for IFNg +874 A/T polymorphism. A p-value < 0.05 was assumed for statistical significance.

Analysis of the IFNg +874 A/T polymorphism showed no significant differences with the level of IFNg. No significant differences were observed either in IFNg +874 A/T polymorphism between the subjects with mild periodontitis and those with severe periodontitis (p  >  0.05). The subjects with severe periodontitis showed marginally but not significantly higher levels of IFNg compared with subjects with mild periodontitis (p  >  0.05).

The polymorphism of IFNg +874 A/T was not associated with the level of IFNg nor with the risk of periodontitis in this study.