IL-37- and IL-35/IL-37-Producing Plasma Cells in Chronic Periodontitis.

Area of Science:

• Immunology
• Periodontology
• Cell Biology

Background:

• Periodontitis is a prevalent chronic inflammatory disease.
• Plasma cells are key immune cells in periodontal lesions, traditionally known for antibody production.
• Emerging evidence suggests plasma cells also produce cytokines, but this role in periodontitis is unexplored.

Purpose of the Study:

• To investigate the presence and function of cytokine-producing plasma cells in chronic periodontitis (CP).
• To identify specific cytokines produced by plasma cells in CP lesions.
• To evaluate the impact of identified cytokines on osteoclast formation, a key process in bone loss.

Main Methods:

• Immunohistochemistry to detect IL-35 and IL-37 levels in gingival tissues.
• Immunofluorescence and confocal microscopy to identify and characterize plasma cell subsets.
• In vitro assays using recombinant IL-35 and IL-37 to assess their effect on osteoclast formation.

Main Results:

• Significantly elevated levels of anti-inflammatory cytokines IL-35 and IL-37 were found in CP gingival tissue.
• CD138+ CD38+ plasma cells were identified as the major immune cell type producing IL-35 and IL-37 in CP lesions.
• Two novel plasma cell subsets, IL-37-producing plasma cells (P_IL-37) and IL-35/IL-37-coproducing plasma cells (P_IL-35/IL-37), were characterized.
• Recombinant IL-35 and IL-37 significantly inhibited osteoclast formation in vitro, suggesting a role in preventing bone loss.

Conclusions:

• Novel subsets of plasma cells, P_IL-37 and P_IL-35/IL-37, are present in chronic periodontitis lesions.
• These plasma cell subsets may play a regulatory role in periodontitis pathogenesis by inhibiting alveolar bone loss.
• The findings suggest a new mechanistic and regulatory target for periodontal disease treatment.