B-cell cytokine responses to Porphyromonas gingivalis in patients with periodontitis and healthy controls

BackgroundCytokine-producing B cells play a well-established role in modifying immune responses in chronic inflammatory diseases. We characterized B-cell cytokine responses against periodontitis-associated bacteria in patients with periodontitis. MethodsBlood and saliva samples were collected from patients with periodontitis grade B (N = 31) or grade C (N = 25), and 25 healthy controls (HCs). Mononuclear cells were stimulated with Porphyromonas gingivalis, Fusobacterium nucleatum, Staphylococcus epidermidis, or Cutibacterium acnes, and B-cell production of tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, interferon (IFN)-gamma, IL-10 and transforming growth factor (TGF)-beta by B cells was assessed by flow cytometry. ResultsHCs had higher baseline frequencies of B cells producing IFN-gamma or TNF-alpha than grade B patients, but only B cells from grade B patients showed significant differentiation into IFN-gamma-, TNF-alpha-, TGF-beta-, or IL-10-producing cells after challenge with P. gingivalis and into IFN-gamma-, TGF-beta-, or IL-10-producing cells after challenge F. nucleatum. Notably, the baseline frequency of IL-10-producing B cells from grade C patients correlated inversely with clinical attachment loss (AL). The major proportion of the IFN-gamma- and TGF-beta-producing B cells were CD27(+) memory cells, while the IL-10-producing B cells were mainly CD27(-)CD5(-). ConclusionsB cells from grade B patients, particularly those harboring P. gingivalis, showed proinflammatory B-cell responses to P. gingivalis. Moreover, the baseline frequency of IL-10-producing B cells in the grade C group correlated inversely with AL, suggesting a diminished immunoregulatory capacity of IL-10-producing B cells in these patients.