Abstract: PURPOSE: To investigate the distribution of Porphyromonas gingivalis(P.g) rag genotypes in patients of chronic periodontitis with chronic obstructive pulmonary disease (COPD). METHODS: Thirty patients with chronic periodontitis and 30 patients with chronic periodontitis complicated with COPD were included. Saliva samples were collected from all subjects. The detection rate and rag genotype of P.g in saliva were detected by 16S rDNA polymerase chain reaction (PCR). SPSS 22.0 software package was used for statistical analysis. RESULTS: The positive rate of P.g was 76.67% in chronic periodontitis patients with COPD, and 63.33% in chronic periodontitis group, there was no significant difference between the two groups (P>0.05). The detection rates of rag-1 genotype in the two groups were 70% and 30.77%, respectively, there was significant difference between the two groups(P<0.05). The detection rates of rag-2, rag-3 and rag-4 in the two groups were not significantly different. CONCLUSIONS: Various rag genotypes can be found in patients of chronic periodontitis with COPD. Rag-1 might have more close correlation with the development of COPD.

Key words: Periodontitis, Chronic obstructive pulmonary disease, Porphyromonas gingialis, Genotype, Rag gene