Expression of Toll-like receptors 2 and 4 in the saliva of patients with systemic lupus erythematosus and chronic periodontitis.

OBJECTIVE The aim of this study was to investigate the expression of salivary Toll-like receptors (TRL) 2 and 4 in patients with systemic lupus erythematosus (SLE) and chronic periodontitis (CP). METHODS A case-control study was conducted with 77 participants (42 SLE and 35 non-SLE) stratified according to CP diagnosis criteria. Periodontal parameters consisted of clinical attachment level (CAL), probing depth (PD), the visible plaque index (VPI), and the gingival bleeding index (GBI). Salivary TRL 2 and 4 expressions were determined by quantitative real-time polymerase chain reaction (RT-PCR). Statistical analysis included Mann-Whitney U test, Kruskal-Wallis test, Spearman's correlation rank, and multiple linear regression. RESULTS Patients with isolated SLE or CP had higher TLR 2 and TLR 4 expression in their saliva samples (P < 0.05). The group with both SLE and CP had lower TLR 2 and 4 expressions (P < 0.05). TLR 2 and TLR 4 showed significant negative correlations with PD, CAL, and GBI in SLE patients, and a significant positive correlation with periodontal parameters in non-SLE patients. CP was independently associated with reduction of TLR2 and TLR4 expression, even after adjusting for clinical data and current drug use. CONCLUSION Reduced TRL 2 and 4 expression in saliva was associated with the presence of CP in SLE patients. Key Points • Patients affected by isolated CP or SLE had higher TLR2 and TLR4 expression. • TLR under-expression may be associated with a worse periodontal status in SLE. • Abnormalities in TLRs expression may increase the susceptibility to periodontitis.