Chemokine Receptor 2 (<i>CXCR2</i>) Gene Variants and Their Association with Periodontal Bacteria in Patients with Chronic Periodontitis

Abstract

Periodontitis, an inflammatory disease caused by subgingival Gram-negative (G-) bacteria, is linked with loss of the connective tissue and destruction of the alveolar bone. In the regulation of inflammatory response, chemokine receptor 2 (CXCR2), a specific receptor for interleukin-8 and neutrophil chemoattractant, plays an important role. The first aim of this study was to investigate the <i>CXCR2</i> gene variability in chronic periodontitis (CP) patients and healthy nonperiodontitis controls in the Czech population. The second aim was to find a relation between <i>CXCR2</i> gene variants and the presence of periodontal bacteria. A total of 500 unrelated subjects participated in this case-control study. 329 CP patients and 171 healthy nonperiodontitis controls were analyzed using polymerase chain reaction techniques for three single-nucleotide polymorphisms (SNPs): +785C/T (rs2230054), +1208T/C (rs1126579), and +1440A/G (rs1126580). A DNA microarray detection kit was used for the investigation of the subgingival bacterial colonization, in a subgroup of CP subjects (<i>N</i> = 162). No significant differences in allele, genotype, haplotype, or haplogenotype frequencies of <i>CXCR2</i> gene variants between patients with CP and healthy controls (<i>P</i> > 0.05) were determined. Nevertheless, <i>Aggregatibacter actinomycetemcomitans</i> was detected more frequently in men positive for the C allele of the <i>CXCR2</i> +785C/T polymorphism (61.8% vs. 41.1%, <i>P</i> < 0.05; OR = 2.31, 95% CI = 1.03-5.20) and for the T allele of the <i>CXCR2</i> +1208C/T variant (61.8% vs. 38.9%, <i>P</i> < 0.05; OR = 2.54, 95% CI = 1.13-5.71). In contrast, no statistically significant associations of <i>CXCR2</i> variants with seven selected periodontal bacteria were found in women. Although none of the investigated SNPs in the <i>CXCR2</i> gene was associated with CP, the <i>CXCR2</i> gene variants can be associated with subgingival colonization of G- bacteria in men with CP in the Czech population.