Association between Periodontitis and Severe Asthma: The Role of IgG Anti-Porphyromonas gingivalis Levels

Abstract

Asthma and periodontitis are both very prevalent worldwide. Although the association between these diseases has been investigated, the biological mechanism underlying this association, especially the role of biological mediators, remains unclear. Thus, the aim of this study was to evaluate serum levels of anti-Porphyromonas gingivalis IgG in subjects with and without severe asthma. A case-control study involving 169 individuals consisted of subjects with severe asthma in addition to others without asthma (control group). An indirect enzyme linked immunosorbent assay (ELISA) was performed to measure serum levels of IgG specific to Porphyromonas gingivalis. Bacterial DNA was extracted from subgingival biofilm samples and real-time polymerase chain reaction (RT-PCR) analysis was performed to quantify Porphyromonas gingivalis levels. No statistically significant differences were observed between case and control groups with respect to levels of IgG specific to Porphyromonas gingivalis whole extract (p=0.484) or rHmuY protein (p=0.903). The relative quantification of Porphyromonas gingivalis was similar between the groups with and without asthma (p=0.553). When participants were regrouped according to a diagnosis of periodontitis, no significant differences were detected between subjects with and without periodontitis, either in serum levels of IgG specific to Porphyromonas gingivalis whole extract (p=0.789) or specific to rHmuY (p=0.630). However, participants with chronic periodontitis had lower levels of Porphyromonas gingivalis in their biofilm than individuals without periodontitis (p=0.001). We hypothesize that the occurrence of asthma exerts an influence over Porphyromonas gingivalis colonization in the biofilm, as well as modulates the production of IgG specific to this pathogen in periodontitis.