Multiplex cytokine analyses in dogs with pyometra suggest involvement of KC-like chemokine in canine bacterial sepsis

• Concentrations of KC-like chemokine were significantly higher in sera from dogs with pyometra compared to healthy dogs and in dogs with sepsis compared to dogs without sepsis in pyometra.
• KC-like concentrations correlated significantly with hematological parameters and morbidity that accompany sepsis.
• Together our findings suggest involvement of KC-like in sepsis and bacterial uterine infection in dogs.

Clinical diagnostic criteria for sepsis (systemic inflammatory response syndrome caused by infection) are unspecific and, therefore, biomarkers for sepsis diagnosis are needed for appropriate treatment and patient survival. Pyometra, a common disease caused by bacterial infection of the uterus, results in sepsis in nearly 60% of cases in dogs. We used dogs with pyometra as a natural model for sepsis and collected serum samples from 39 dogs, of which 22 with pyometra and 17 healthy controls. Dogs with pyometra were further grouped into dogs with sepsis (n = 18) and without sepsis (n = 4). Serum concentrations of a panel of cytokines, including keratinocyte-derived chemokine (KC)-like, granulocyte-macrophages colony stimulating factor (GM-CSF), interleukin (IL)-2, IL-4, IL-6, IL-7, IL-8, IL-10, IL-15, IL-18, chemokine C-X-C motif ligand (CXCL)10 and tumor necrosis factor (TNF)-α, were measured using multiplex analyses. Serum C-reactive protein (CRP) levels were determined using an automated immunoturbidimetric assay. In addition to physical examination hematological and serum biochemical analyses were performed to evaluate the overall status of the dogs. Significantly higher concentrations of KC-like (757 vs 304 pg/ml) were detected in dogs with pyometra as compared to healthy dogs. Within the pyometra group, dogs with sepsis compared to dogs without sepsis had a higher KC-like concentration (873 vs 300 pg/ml). Hemoglobin levels were significantly lower in dogs with pyometra compared to healthy dogs, regardless of the presence or absence of sepsis, and correlated negatively with KC-like. KC-like concentrations correlated positively with CRP, number of hospitalization days, number of monocytes, concentrations of IL-8, and percentage band neutrophils. Our data suggest that bacterial infection triggers the expression of KC-like and further studies are warranted of KC-like as a possible biomarker for diagnosing sepsis and uterine bacterial infection in dogs.