Hematologic effects of subcutaneous administration of recombinant human granulocyte colony-stimulating factor (filgrastim) in healthy alpacas.
OBJECTIVE
To determine the effects of SC administration of filgrastim on cell counts in venous blood and bone marrow of healthy adult alpacas.


METHODS
10 healthy alpacas.


METHODS
Alpacas were randomly assigned to receive treatment with filgrastim (5 microg/kg, SC; n=5) or an equivalent volume of physiologic saline (0.9% NaCl) solution (5) once a day for 3 days. Blood samples were obtained via jugular venipuncture 1 day prior to treatment and once a day for 5 days commencing 24 hours after the first dose was administered. Complete blood counts were performed for each blood sample. Bone marrow aspirates were obtained from the sternum of each alpaca 48 hours before the first treatment was administered and 72 hours after the third treatment was administered. Myeloid-to-erythroid cell (M:E) ratio was determined via cytologic evaluation of bone marrow aspirates.


RESULTS
In filgrastim-treated alpacas, substantial increases in counts of WBCs and neutrophils were detected within 24 hours after the first dose was administered. Band cell count and percentage significantly increased 24 hours after the second dose. Counts of WBCs, neutrophils, and band cells remained high 48 hours after the third dose. Red blood cell counts and PCV were unaffected. The M:E ratio also increased significantly after treatment with filgrastim.


CONCLUSIONS
Filgrastim induced rapid and substantial increases in numbers of circulating neutrophils and M:E ratios of bone marrow in healthy alpacas. Therefore, filgrastim may be useful in the treatment of camelids with impaired bone marrow function.
Department of Clinical Sciences, College of Veterinary Medicine, Oregon State University, Corvallis, OR 97331, USA.
Erica C
EC
McKenzie
Susan J
SJ
Tornquist
M Elena
ME
Gorman
Christopher K
CK
Cebra
Mark E
ME
Payton
D000818:Animals; D001853:Bone Marrow / Q000187:drug effects*; D002161:Camelids, New World / Q000097:blood*; D004906:Erythrocyte Count; D000069585:Filgrastim; D016179:Granulocyte Colony-Stimulating Factor / Q000494:pharmacology*; D006400:Hematocrit / Q000662:veterinary; D006410:Hematopoiesis / Q000187:drug effects*; D007958:Leukocyte Count / Q000662:veterinary; D018655:Lymphocyte Count / Q000662:veterinary; D009504:Neutrophils / Q000166:cytology / Q000187:drug effects; D010976:Platelet Count; D011897:Random Allocation; D011994:Recombinant Proteins
D011994:Recombinant Proteins; D016179:Granulocyte Colony-Stimulating Factor; D000069585:Filgrastim