CXCL8 and periodontitis: On the other hand, absence of cytokine response in hESC-MSCs indicates the differential response of these cells under bacterial challenge that could alter the progression of periodontal disease differently. A. actinomycetemcomitans has been associated with aggressive forms of periodontitis, and one possible mechanism whereby this pathogen could contribute to rapid destruction of periodontal tissues is by stimulating the fibroblasts to produce IL-6 and IL-8 [41].