Chemokines and chemokine receptors expression in human periapical disease

Periapical lesions are thought to be the result of local inflammatory response mediated by immunocompetent cells infiltration and production of mediators such as chemokines, which play a crucial role in the recruitment of selective leukocytes subsets. Objectives: the objective of this study was to evaluate the expression of chemokines and their receptors in human apical periodontitis. Methods: we used Real Time PCR to determine the expression of chemokines and their receptors in samples obtained from clinically healthy gingival tissues (n=3), periapical granulomas (n=14) and inflammatory periradicular cysts (n=5). The inflammatory cell infiltrate was characterized by immunohistochemistry. Results: we observed a similar population of CD8+ cells in both types of lesions and an increase of CD4+ T lymphocytes and macrophages in granulomas compared to cysts. The percentual of T memory cells CD45RO+ was similar in both lesions. When comparing with controls, cysts and granulomas showed an increased mRNA expression of RANTES, IP-10 e MCP-1. We also observed an increase on mRNA expression of CCR3, CCR5, CXCR1 and CXCR3 receptors in cysts compared to granulomas. The expression of IL-8, MIP-1alpha and MIP-1beta in periapical samples was similar to healthy gingival tissues controls. Conclusions: the augment of expression of Th1 type receptors (CCR5 and CXCR3) and their ligands (RANTES and IP-10) respectively, and Th2 type (CCR3 and MCP-1), suggests the concomitant occurrence of Th1 and Th2 responses in both periapical lesions. The expression of chemokines and their receptors may modulate the formation and progression of periapical lesions and to be responsible for maintenance of leukocytes infiltration and inflammation and also for bone resorption in apical periodontitis. (Financial support: FAPESP.)