Citrullination in the periodontium—a possible link between periodontitis and rheumatoid arthritis
August 2015
Date:
13 Aug 2015
Abstract
Objectives
The
aim of the present study was to assess human and bacterial
peptidylarginine deiminase (PAD) activity in the gingival crevicular
fluid (GCF) in the context of serum levels of antibodies against
citrullinated epitopes in rheumatoid arthritis and periodontitis.
Materials and methods
Human PAD and Porphyromonas gingivalis-derived
enzyme (PPAD) activities were measured in the GCF of 52 rheumatoid
arthritis (RA) patients (48 with periodontitis and 4 without) and 44
non-RA controls (28 with periodontitis and 16 without). Serum antibodies
against citrullinated epitopes were measured by ELISA. Bacteria being
associated with periodontitis were determined by nucleic-acid-based
methods.
Results
Citrullination
was present in 26 (50 %) RA patients and 23 (48 %) controls. PAD and
PPAD activities were detected in 36 (69 %) and 30 (58 %) RA patients,
respectively, and in 30 (68 %) and 21 (50 %) controls, respectively.
PPAD activity was higher in RA and non-RA patients with periodontitis
than in those without (p = 0.038; p = 0.004), and was detected in 35 of 59 P. gingivalis-positive samples, and in 16 of 37 P. gingivalis-negative samples in association with high antibody levels against that species.
Conclusions
PAD and PPAD activities within the periodontium are elevated in RA and non-RA patients with periodontitis. PPAD secreted by P. gingivalis
residing in epithelial cells may exert its citrullinating activity in
distant regions of the periodontium or even distant tissues.
Clinical relevance
In
periodontitis, the citrullination of proteins/peptides by human and
bacterial peptidylarginine deiminases may generate antibodies after
breaching immunotolerance in susceptible individuals.
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