In vitro, IL-17E suppressed IL-17A and P. gingivalis induced chemokine-expression by inhibiting phosphorylation of the NF-kB p65 subunit, which indicated that in the pathogenesis of periodontitis the serum IL-17A-IL-17E ratio might be a marker of disease severity while IL-17E is opposing IL-17A. The gene discussed is IL17A; the disease is periodontitis.