Elevated pro-inflammatory cytokines and chemokines in saliva of cats with feline odontoclastic resorptive lesion.

Feline odontoclastic resorptive lesion (FORL) is an inflammatory oral disease of unknown aetiopathogenesis that affects between 20% to 75% of cats. Twenty immune-associated molecules were measured in saliva of 25 healthy and 40 cats with FORL using a multiplex assay. No statistically significant differences were observed in the levels of these proteins between the healthy group and the diseased group of cats. A two-step cluster analysis of the oral microbiome and salivary cytokine data identified two subgroups of cats with FORL: FORL-1 (subset of cats with a less diverse oral microbiome) and FORL-2 (diseased cats with a microbiome similar to that of healthy animals). The level of some key proinflammatory cytokines (IL-1β, IL-12p40) and chemokines (IL-8, RANTES, KC) were significantly higher in the FORL-1 subgroup than in the FORL-2 subgroup and the healthy group. In addition, TNF-α levels were greater in the FORL-1 subgroup than in the FORL-2 subgroup. These increases in pro-inflammatory cytokines and chemokines indicate active ongoing inflammation that may promote the osteoclastic/odontoclastic activity associated with FORL.