title: Thrombocytopenia in dogs induced by granulocyte-macrophage colony-stimulating factor: increased destruction of circulating platelets.
abstract: Administration of recombinant canine granulocyte-macrophage colony-stimulating factor (rcGM-CSF) to normal dogs in previous studies induced an increase in peripheral blood neutrophils and a dose-dependent decrease in platelet counts. In six dogs that received the highest tested dose of rcGM-CSF (50 micrograms/kg/d) for a minimum of 12 days, the mean nadir of the platelet count was 46,000/microL (range, 4,000 to 91,000/microL) on day 9 +/- 1.1 after starting therapy, compared with a mean baseline platelet count of 398,000/microL (range, 240,000 to 555,000/microL). In three dogs, survival of autologous 111In-labeled platelets was reduced from a mean of 4.9 days to 1.3 days during the administration of rcGM-CSF. Biodistribution studies with gamma camera imaging indicated that there was an increase in mean hepatic uptake during the administration of rcGM-CSF, from 15% to 44% of the total injected 111In-labeled platelets at 2 hours, whereas splenic uptake was not significantly changed. In contrast, in two evaluable dogs who were recipients of 111In-labeled platelets from matched allogeneic donors receiving rcGM-CSF, platelet survival was not reduced and no increased hepatic uptake was noted. A third dog became alloimmunized to the matched donor platelets and was not evaluable. Immunohistologic studies of liver and spleen were performed with monoclonal antibodies specific for canine gpIIb/IIIa and P-selectin in dogs treated with rcGM-CSF and compared with untreated controls. On treatment, a marked reduction of platelets in the red pulp of the spleen was evident, and in general, the presence of platelet antigen in the liver was unchanged. Therefore, platelets were not being sequestered, but destroyed in the liver and spleen. The platelet antigens, P-selectin and gpIIb/IIIa, were identified in association with Kupffer cells in the liver, but no difference in the number of distribution of these Kupffer cells was found between controls and rcGM-CSF-treated dogs. In the spleen during rcGM-CSF treatment, most platelet antigens were associated with large mononuclear cells in the marginal zone. During administration of rcGM-CSF, CD1c and CD11c expression was increased on Kupffer cells. Platelet P-selectin expression and binding of leukocytes to circulating platelets were unchanged from baseline studies with rcGM-CSF treatment. In conclusion, during the administration of rcGM-CSF to dogs, a local process in the liver and spleen is induced resulting in thrombocytopenia.(ABSTRACT TRUNCATED AT 400 WORDS)
authors.affiliation: Fred Hutchinson Cancer Research Center, Seattle, WA 98104, USA.
authors.forename: R A
authors.initials: RA
authors.lastname: Nash
authors.forename: S A
authors.initials: SA
authors.lastname: Burstein
authors.forename: R
authors.initials: R
authors.lastname: Storb
authors.forename: W
authors.initials: W
authors.lastname: Yang
authors.forename: K
authors.initials: K
authors.lastname: Abrams
authors.forename: F R
authors.initials: FR
authors.lastname: Appelbaum
authors.forename: T
authors.initials: T
authors.lastname: Boone
authors.forename: H J
authors.initials: HJ
authors.lastname: Deeg
authors.forename: L D
authors.initials: LD
authors.lastname: Durack
authors.forename: F G
authors.initials: FG
authors.lastname: Schuening
mesh_terms: D000818:Animals; D001792:Blood Platelets / Q000187:drug effects* / Q000473:pathology; D002470:Cell Survival / Q000187:drug effects; D004285:Dogs; D005260:Female; D005434:Flow Cytometry; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000494:pharmacology* / Q000633:toxicity; D006410:Hematopoiesis / Q000187:drug effects*; D016298:Hematopoietic Cell Growth Factors / Q000494:pharmacology; D008099:Liver / Q000166:cytology / Q000187:drug effects / Q000473:pathology; D008297:Male; D010976:Platelet Count / Q000187:drug effects; D017713:Platelet Transfusion; D011994:Recombinant Proteins / Q000494:pharmacology / Q000633:toxicity; D013156:Splenectomy; D013921:Thrombocytopenia / Q000139:chemically induced*; D013997:Time Factors; D014184:Transplantation, Homologous
chemical_list: D016298:Hematopoietic Cell Growth Factors; D011994:Recombinant Proteins; D016178:Granulocyte-Macrophage Colony-Stimulating Factor