Periodontal and Serum Protein Profiles in Patients With Rheumatoid Arthritis Treated With Tumor Necrosis Factor Inhibitor Adalimumab

Background: Tumor necrosis factor (TNF)-alpha inhibitor has been shown to affect the periodontal condition of patients with rheumatoid arthritis (RA). The aim of the present study is to assess the effect of a fully humanized anti-TNF-alpha monoclonal antibody, adalimumab (ADA), on the periodontal condition of patients with RA and to compare serum protein profiles before and after ADA therapy. Methods: The study participants consisted of 20 patients with RA treated with ADA. Clinical periodontal and rheumatologic parameters and serum cytokine levels were evaluated at baseline and 3 months later. Serum protein spot volume was examined with two-dimensional sodium dodecyl sulfate polyacrylamide gel electrophoresis. Proteins with significant difference in abundance before and after ADA therapy were found and identified using mass spectrometry and protein databases. Results: The patients showed a significant decrease in gingival index (P = 0.002), bleeding on probing (P = 0.003), probing depth (P = 0.002), disease activity score including 28 joints using C-reactive protein (P < 0.001), and serum levels of TNF-alpha (P < 0.001) and interleukin-6 (P < 0.001) after ADA medication, although plaque levels were comparable. Among a total of 495 protein spots obtained, nine spots were significantly decreased in abundance at reassessment, corresponding to complement factor H, phospholipase D, serum amyloid A, complement component 4, and alpha-1-acid glycoprotein (P < 0.01). Conclusion: These results suggest a beneficial effect of ADA therapy on the periodontal condition of patients with RA, which might be related to differences in serum protein profiles before and after ADA therapy.