The purpose of this study was to investigate the changes of circulating concentrations of platelet derived growth factor BB (PDGF-BB) and transforming growth factor beta 1 (TGF-?1) in dogs with generalised demodicosis. Fifteen dogs with generalised demodicosis diagnosed on clinical findings and microscopic examination of the cutaneous scrapings and 10 healthy dogs were included in the study. Circulating concentrations of PDGF-BB and TGF-?1 were measured by commercial specific ELISA assays. Marked and significant increases in plasma PDGF-BB and in serum TGF-?1 concentrations were evidenced in diseased dogs. Circulating PDGF-BB concentrations were closely and positively associated with TGF-?1 concentrations in affected dogs (r = 0.92, p < 0.001). These results indicate that the increased concentrations of circulating PDGF-BB and TGF-?1 play a pivotal role in the pathogenesis of the canine demodicosis
