Feline chronic gingivostomatitis (FCGS) is a chronic inflammatory condition affecting the oral cavity. Treatment options are limited, as the cause of FCGS is poorly understood. Microbial factors and alterations in the innate immune response are suggested contributors.

Toll-like receptors (TLRs) are important in early host defense. After binding to ligands, TLRs activate adapter molecules, leading to induction or suppression of genes that influence the inflammatory response. Putative bacterial pathogens involved in the pathogenesis of FCGS may elicit characteristic cytokine responses by activating specific TLRs. Expressions of TLR and cytokine mRNAs were assessed in cats with and without FCGS and in the presence or absence of the most commonly identified FCGS bacterial pathogens. The study found association between the clinical severity of FCGS and the presence of several putative pathogens, especially feline calicivirus and Tannerella forsythia. These appear to be particularly capable of increasing TLR and cytokine expression, thus suggesting involvement in the etiopathogenesis of FCGS.

The influence of oral bacteria on tissue levels of Toll-like receptor and cytokine mRNAs in feline chronic gingivostomatitis and oral health. Dolieslager SM, Lappin DF, Bennett D, et al. VET IMMUNOL IMMUNOPATHOL 151:263-274, 2013.