Evaluation of genetic polymorphism of interleukin-1β (rs16944) in chronic and aggressive periodontitis in a group of the Bengali population of West Bengal, India

Abstract

Objectives: The genetic basis of periodontitis was demonstrated by formal genetic studies which were focused on a range of various candidate genes selected for their roles in the immune system like genes of the interleukins (ILs) which regulate the intensity of host immunity-inflammatory response. This regulation of host response may be associated with the genetic polymorphisms, specific single-nucleotide polymorphisms of the genes of various ILs. Interleukin-1 (IL-1) is a principal mediator of inflammatory responses acting on many cell types and is itself produced by many different cells, including macrophages, endothelial cells, B cells, fibroblasts, epithelial cells, astrocytes, and osteoblasts in response to microorganisms, bacterial toxins, and complement components. In the present study, an attempt has been made to explore the role of IL-1β-511 (rs16944) genetic polymorphism in chronic as well as aggressive periodontitis in a group of the Bengali population of West Bengal, India. Materials and Methods: A total of 88 Bengali patients of both sexes were recruited in this study and they were divided into three groups: Group A (chronic periodontitis group), Group B (aggressive periodontitis group), and Group C (healthy control). The clinical parameters taken into consideration in the assessment of chronic and aggressive periodontitis were plaque index, calculus index, gingival index, probing pocket depth (PPD), and clinical attachment loss (CAL). A 3 ml of peripheral venous blood was collected from each selected participant and transferred to 3% EDTA containing serum vial and stored at −20°C for DNA extraction. DNA extraction was performed by the phenol chloroform method and ethanol precipitation. Genotyping of extracting DNA samples was carried out for locus IL-1β-511 (rs16944) by real-time polymerase chain reaction. Hardy–Weinberg equilibrium was tested for the gene polymorphism and association between genotypes and cases was examined by odds ratio with 95% confidence interval (CI) and Chi-square analysis using R programming software. Allelic frequencies were calculated according to the number of different alleles observed and the total number of alleles examined. Statistical significance was defined as P < 0.05. Results: On analysis of minor allele frequencies of total periodontitis cases and control, the results were found to be statistically insignificant with P = 0.9799. Minor allele frequency of overall periodontitis cases and controls was 0.405 and 0.403, respectively; the odds ratio was 1.008 and 95% CI ranges from 0.53 to 1.88. Conclusion: The present study suggested no association of single-nucleotide polymorphism of IL-1β-511 (rs16944) with total periodontitis cases (both chronic periodontitis and aggressive periodontitis) in the present study cohort.