Toll-like receptor 2 expression in refractory periapical lesions

Desai SV, Love RM, Rich AM, Seymour GJ. Toll‐like receptor 2 expression in refractory periapical lesions. International Endodontic Journal, 44, 907–916, 2011. Aim To investigate the expression of TLR2 in refractory periapical lesions. Methodology Refractory periapical lesion biopsies were histopathologically and clinically categorized into asymptomatic periapical granuloma (n = 10), symptomatic periapical granuloma (n = 10) or periapical cyst (n = 10) and prepared for immunohistochemical staining using antibodies to TLR2, CD3 and CD19 or staining with methyl green pyronin. Sections were viewed under light microscopy and the presence or absence of the target cells was correlated with the histopathological and clinical data. Additionally, TLR2 expression was quantified by counting TLR+ cells. Results Various mononuclear inflammatory cells in the bacteria‐induced periapical lesions were reactive to TLR2 antibody, with many showing morphological similarities to lymphocytes and plasma cells. Lymphocytes were the most numerous cells in the inflammatory infiltrate. In refractory periapical granuloma, CD3+ T cells were more numerous, whereas in periapical cysts, CD19+ B cells were more numerous. There was a statistically significant (P