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Figure 3. Chemokines in healthy and diseased periodontal tissues. A schematic representation of chemokine networks in periodontal tissues, in which the bacterial biofilm hosting periodontopathogens is thought to trigger the expression of chemokines and other inflammatory mediators in gingival tissues. In healthy conditions (left), a slight expression of IL-8/CXCL8 in junctional epithelium is correlated with the subclinical inflammatory infiltrate, composed basically of polymorphonuclear leukocytes (PMNs). In addition, 6Ckine/CCL21 expression in lymphatic vessels is exclusively found in healthy periodontal tissue. In contrast, in periodontitis tissues, an intense expression of several chemokines can be observed. An increased expression of IL-8/CXCL8 is found in junctional epithelium, and directs an intense PMN influx to these areas. In periodontal connective tissues, chemokines such as MCP-1/CCL2 and RANTES/CCL5 can drive the migration of macrophages, IP-10/CXCL10 and MIP-1
/CCL3 are chemoattractants of Th1-type lymphocytes, and chemokines such as MDC/CCL22 and TCA-3/I-309/CCL1 can attract Th2-type lymphocytes. The accumulation of B-cells can be driven by BCA-1/CXCL13, while chemokines such as MIP-1/CCL3 and SDF-1/CXCL12 can also be involved in the migration and activation of osteoclasts, thereby contributing to disease severity.
