Effect of Recombinant Canine Granulocyte Colony‐stimulating Factor on Peripheral Blood Neutrophil Counts in Normal Cats

Abstract

Recombinant canine granulocyte colony‐stimulating factor (rcC‐CSF) was administered subcutaneously at a dosage of 5 μg/kg/day to five healthy, young adult cats for 42 days. Mean neutrophil counts ± standard deviation increased significantly (P > 0.001) from 10,966/μL ± 2324 to 30,688/μL ± 5296 within 24 hours after administration of the first dosage of rcG‐CSF. Mean neutrophil counts reached 52,978/μL ±11,207 on day 6, representing a second significant increase (P > 0.01) over the previous 5 days. Mean neutrophil counts continued to increase, reaching 66,994/μL ± 12,419 on day 14, then remaining within a range of 66,994 to 87,839/μL throughout the remainder of the study. The maximum mean neutrophil count was 87,839/μL ± 8,695 on day 42. Neutrophil counts remained high until the administration of recombinant canine granulocyte colony‐stimulating factor was discontinued 42 days after initiation of therapy. Once the rcG‐CSF administration was discontinued, neutrophil counts returned to pretreatment values within 5 days. There were no significant changes in numbers of any of the other cell lines. There was no clinically significant toxicosis associated with the administration of rcGCSF. © 1993 American College of Veterinary Internal Medicine