Abstract
BACKGROUND: Periodontitis (PD) is a chronic infectious inflammatory disease that affects the tissues supporting teeth and results in a progressive deterioration of the alveolar bone. Rheumatoid arthritis (RA), a systemic autoimmune disease that has been associated with increased severity of periodontal disease. This study aimed to evaluate the salivary levels human leukocyte antigen-DR4 (HLA-DR4), matrix metalloproteinase-8 (MMP-8), and anti-citrullinated protein antibody (ACPA), and to assess their diagnostic potential using ROC curve analysis in periodontitis patients with and without rheumatoid arthritis. METHODS: The study included three groups; thirty patients with PD, thirty patients with PD and RA, and twenty healthy control participants. Clinical periodontal parameters [plaque Index (PLI), bleeding on probing (BOP), probing pocket depth (PPD), and clinical attachment loss (CAL)] were assessed. Salivary biomarkers were analyzed by enzyme-linked immunosorbent assay (ELISA), and the microbial load of Porphyromonas gingivalis ( P. gingivalis) was determined using quantitative real time polymerase chain reaction (qRT-PCR). RESULTS: Our findings showed that salivary HLA-DR4 levels were significantly lower in patient groups compared with healthy controls (P = 0.000), whereas salivary MMP-8 and ACPA levels were significantly elevated in patients (P = 0.034) and (P = 0.001) respectively, with no significant differences between the patient groups(P > 0.05). On the other hand, microbial load was significantly higher in the PD with and without RA groups than that in controls (P = 0.001), with a positive correlation between microbial load and CAL in the PD-RA group.