Background A possible infectious trigger for RA is suspected at the gingival site. Emerging data implicates the microbiome in RA pathogenesis. Mucosal sites exposed to a high load of bacterial antigens, such as the periodontium, may represent the initial site of autoimmune generation. If validated, these findings could lead to the discovery of potential biomarkers and therapeutic approaches in the pre-clinical and clinical phases of RA(1).
Objectives To determine the organisms causing periodontitis in Egyptian RA patients and their relation to serum and gingival ACPA level and other disease parameters.
Methods This study was carried out on 100 Egyptian RA patients fulfilling the 2010 ACR/EULAR classification criteria for RA and of less than 5 years disease duration, recruited from Rheumatology Unit, outpatient clinic and Dental clinic at Alexandria Main University Hospital. RA disease activity was assessed by applying DAS28 and functional state of the patients was assessed by applying HAQ score. Dental examination, serum RF, and ACPA in serum and GCF were done for all patients. X-ray of both hands to detect erosions and severity of the disease. Gingival Crevicular Fluid (GCF) culture was performed for all cases with periodontitis for the three micro-organisms most reported in the literature to produce periodontitis (Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, and Prevotella intermedia).
Results Of the 100 patient, 66 patient had periodontitis, for them, GCF culture was performed and Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, and Prevotella intermedia were found in 60.6%, 15.2%, and 30.3% of RA patients with periodontitis respectively. Gingival ACPA was detected in the 3 studied organisms, being of significant higher level with P.gingivalis than P.intermedia positive cases (p=0.047). No statistical significant difference detected on comparing P.gingivalis with A.actinomycetemcomitans or A.actinomycetemcomitans with P.intermedia. A. actinomycetemcomitans positive cases were associated with significantly higher level of CRP than P. intermedia positive cases (p=0.029), while no statistical significant difference was detected between P.gingivalis and A. actinomycetemcomitans or P. intermedia positive cases. There was no statistical significant difference between the three studied organisms regarding serum ACPA level, DAS 28, HAQ score, or X-ray findings of hands.
Conclusions P.gingivalis is the most prevalent periodontal microbiota in Egyptian RA patients with periodontitis, that associated with significant higher level of gingival ACPA. None of the detected organisms correlated with the degree of RA activity or other disease parameters, apart from significantly higher CRP level with A. actinomycetemcomitans.
Brusca SB, Abramson SB, Scher JU. Microbiome and mucosal inflammation as extra-articular triggers for rheumatoid arthritis and autoimmunity. Curr Opin Rheumatol 2014;26:101–7.
Disclosure of Interest None declared