Effects of filgrastim administration in the treatment protocol of Feline Panleukopenia Virus infected cats

This study aimed to evaluate the efficacy of filgrastim, a human granulocyte colony-stimulating factor (hG-CSF), in regulating the immune response and improving therapeutic outcomes in cats infected with Feline Panleukopenia Virus (FPV). Additionally, it sought to compare the effects of subcutaneous and intravenous administration of filgrastim. FPV, particularly in young cats, causes severe immunosuppression and hematological abnormalities, resulting in a significant disease burden. This study included 39 cats of various breeds and genders, aged between 1 and 12 months, presenting with complaints such as weakness, lethargy, fever (or absence thereof), anorexia, vomiting, and diarrhea. These cats were admitted to Mersin Petmarin Veterinary Clinic and were diagnosed with Feline Panleukopenia based on positive fecal antigen test results. The diagnosed cats were randomly assigned to three groups: control (n=13), experimental 1 (Filgrastim SC, n=13), and experimental 2 (Filgrastim IV, n=13). Cats in the control group received standard supportive treatment, those in experimental 1 received subcutaneous filgrastim, and those in experimental 2 received intravenous filgrastim. Filgrastim was administered in both experimental groups at a dose of 5 µg/kg once daily for three days in addition to standard supportive therapy. Routine clinical examinations and blood sampling were performed for the enrolled cats at baseline (0 hours) and on days 4 and 7 of the treatment. Blood samples were collected from the vena cephalica antebrachii into K3-EDTA tubes for complete blood count analysis. Total leukocyte (WBC), lymphocyte (LYM), monocyte (MON), neutrophil (NEU), erythrocyte (RBC), hematocrit (HCT), and platelet (PLT) levels were measured from these samples. When the hematological findings of the control, experimental 1 and 2 groups were analyzed, significant differences were observed in WBC and LYM counts between days 0 and 7 in all three groups. While no significant differences were detected in NEU and MON counts between days 0 and 7 in the control group, significant differences were observed in both experimental groups. No significant differences were identified in RBC and HCT counts across all three groups. However, a significant difference in PLT count was observed in experimental 1, whereas no significant difference was detected in the control or experimental 2 groups. By the end of the study, 35 cats recovered from the disease, while 4 cats died. In conclusion, filgrastim treatment was found to be effective in improving clinical parameters and correcting hematological abnormalities in cats with FPV infection. Keywords: Feline Panleukopenia; Filgrastim; Leukopenia; Neutropenia