Periodontitis is an inflammatory oral disease caused by multifactorial intrinsic and extrinsic agents, including Gram-negative bacteria such as Porphyromonas gingivalis.
Objective: To evaluate if there is difference in the serum levels of IgA, IgG and IgG subclasses reactive to Porphyromonas gingivalis in subjects with different periodontal conditions.
Methods: The study included 89 patients divided into four groups: 29 subjects with moderate or severe chronic periodontitis (CP), 12 with aggressive periodontitis (AP), 22 with gingivitis or mild periodontitis (GP), and 26 healthy controls (HC). Humoral response was assayed by enzyme-linked immunosorbent assay (ELISA) to verify serum levels of IgG, IgG1, IgG2, IgG3, IgG4 and IgA serum levels reacting to crude P. gingivalis ATCC 33277 sonicate extract and fraction IV, an enrichment of the immunoreactive bands of the crude extract obtained by chromatography.
Results: IgA, IgG (p < 0.01), IgG2, IgG3 and IgG4 serum level reactions to fraction IV were higher in the CP group compared with the healthy control. The CP group had higher levels of IgG and IgG4 to both antigens than the GP group, and higher levels of IgG and IgG4 to sonicate extract than the AP group. There were statistically significant differences in serum levels of IgG to both antigens (p < 0.01), IgG2 to fraction IV (p < 0.01), IgG3 to fraction IV (p < 0.05) and IgG4 to both antigens (p < 0.05) between AP and HC groups. IgG1 titers to sonicate extract were significantly higher (p < 0.05) in the GP group in comparison to the AP group.
Conclusions: The findings of this study suggest that there are differences in the serum levels of IgA, IgG and IgG subclasses in patients with different periodontal conditions.