T-lymphocyte and cytokine expression in human inflammatory periapical lesions

Lymphocytes, among many cells, express different sets of cytokines, chemokines, and receptors, which are considered important mediators of periapical immune response to infection.

The aim of this study was to evaluate the mRNA expression of CD4(+)CD28(+) and CD8(+) T genes and the gene expression of interferon-γ, tumor necrosis factor-α, interleukin (IL)-1β, IL-17A, IL-10, CCL2/MCP-1, CCL4, CCL5, CXCR4, CCR5, and receptor activator for nuclear factor kappa B ligand (RANKL) in periapical interstitial fluid from human root canal infections. The samples were collected immediately after root canal cleaning and 7 days later (restrained root canal bacterial load) to characterize those gene expressions.

Real-time polymerase chain reaction demonstrated significantly higher levels of CD4(+)CD28(+) and CD8(+) T-cell markers in the former root canal condition and an increase of IL-10 and CXCR4, followed by a decrease of proinflammatory cytokines such as RANKL, interferon-γ, IL-1β, and CCL5.

Analyses of T-lymphocyte and cytokine expression in periapical area were able to show that distinct root canal conditions might play regulatory roles in controlling local immune/inflammatory processes.