Noticeable immune dysregulation-and-suppression in parvovirus affected dogs

Abstract

Canine parvovirus type 2 (CPV-2) is one of the most common causes of infectious diarrhea in small animals, with high mortality and morbidity. Information on the specific treatment option(s) for CPV diseases (CPVD) is unachievably little. So, the treatment is mainly supportive one. Disruption of dog's innate immune system in viral diseases simply occurs; presumably, the CPV-2 may change the level of some TLRs, interleukins, CD4 and CD8 in the leukocytes of CPVD dogs, and disruptive activities of these immune molecules might be attributable to severe CPVD in dogs. Study on the role of the key immune molecules in CPVD is rare. Herein, by conducting and relating the clinical, para-clinical, immunological and molecular diagnostic tests, we tried to establish how some key immune molecules behave in blood of parvovirus affected dogs. As such, in the 1st study, the mRNA levels of TLR2, TLR4, TLR9, IL-1β, IL-6, CD4 and CD8 genes in the leukocytes of CPVD were assessed with quantitative (q)RT-PCR along with CPV-2 detection by rapid immunochromatography and PCR tests. In a 2nd study, the same measurements as in the 1st study were evaluated in two groups of mild versus severe clinical signs of CPVD. Both in the 1st and the 2nd studies leukopenia, much more pronounced in the severe CPVD, and immune dysregulation were observed. In the 1st study, a noticeable increase in the mRNA levels of TLR2 and TLR4 was detected with a slight decrease in TLR9 and a significant decrease in the expression of IL-1β, IL-6, CD4 and CD8 in leukocytes of CPV-infected dogs. Compared to the mild CPVD, the intense of downregulating effects on those immune molecules in the 2nd study was remarkably much more pronounced in the severe CPVD. Overall, it proves strong immune dysregulation and suppression/incompetence and potential T-cells exhaustion in severely CPV-2-affected dogs. Technically and clinically, this would be substantially applicable in canine medicine. By targeting those key immune molecules and their signaling pathways, new clinicodiagnostic approaches for CPVD can be evolved, and biotechnicoclinically this would be substantially applicable in all physiopathological conditions of dogs.