Toll-like receptors 2 expression in mediastinal lymph node of patients with sarcoidosis

BACKGROUND: Toll-like receptors (TLRs) play a vital role as a first defense mechanism linking the innate with the adaptive immune system. Prior studies showed that TLR2 participated in immune responses of sarcoidosis. However, the role of TLR2 in the progression of mediastinal lymph nodes associated with sarcoidosis is still unknown. The current study aims to investigate the expression of Toll-like receptors 2 (TLR2) in mediastinal lymph nodes of patients with sarcoidosis. METHODS: Mediastinal lymph nodes biopsy specimens were collected from 10 patients with sarcoidosis and 11 normal controls. The expression of TLR2 in mediastinal lymph nodes was detected by immunohistochemistry. RESULTS: In mediastinal lymph nodes specimens, immunohistochemical examination revealed that expression of TLR2 could be detected in sarcoidosis patients, while it was scarcely detected in the mediastinal lymph nodes of control. The mean optical density of TLR2 in mediastinal lymph nodes of sarcoidosis was significantly higher than controls (124.9±24.3 vs. 92.6±35.2, P=0.026). Among patients with sarcoidosis, correlation analysis showed that the mean optical density of TLR2 in mediastinal lymph nodes positively correlated with the level of 24-hour urinary calcium (R=0.781, P=0.038). CONCLUSIONS: The expression of TLR2 was upregulated in mediastinal lymph nodes of sarcoidosis patients. The expression of TLR2 in mediastinal lymph nodes was associated with the level of 24-hour urinary calcium, suggesting that TLR2 might become another predictor of disease activity.