title: Flow cytometric detection of platelet-bound antibody in three horses with immune-mediated thrombocytopenia.
abstract: Immune-mediated thrombocytopenia (IMT) is a sporadic cause of thrombocytopenia in horses for which it is difficult to establish a definitive diagnosis. In this report, we describe 3 horses with severe thrombocytopenia in which flow cytometric analysis of platelets for surface-bound IgG was used in an attempt to substantiate a provisional diagnosis of IMT. A distinct proportion (4.28%, 5.04%, and 7.95%) of platelets with surface-bound IgG was detected in the 3 thrombocytopenic horses, but not in 6 healthy horses (0.03% to 0.15%) or 6 horses with colic (0.00% to 1.21%). These results, in conjunction with elimination of other potential causes of the thrombocytopenia, established a diagnosis of IMT. The horses were treated with glucocorticoids alone or in combination with azathioprine, and the thrombocytopenia gradually resolved. Flow cytometric detection of platelet-bound IgG was readily performed and may be a useful adjunct for the diagnosis of IMT.
authors.affiliation: Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, ON N1G 2W1, Canada.
authors.forename: M Kimberley J
authors.initials: MK
authors.lastname: McGurrin
authors.forename: Louis G
authors.initials: LG
authors.lastname: Arroyo
authors.forename: Dorothee
authors.initials: D
authors.lastname: Bienzle
mesh_terms: D000818:Animals; D001323:Autoantibodies / Q000097:blood*; D001379:Azathioprine / Q000627:therapeutic use; D001792:Blood Platelets / Q000276:immunology*; D005260:Female; D005434:Flow Cytometry / Q000662:veterinary*; D005938:Glucocorticoids / Q000627:therapeutic use; D006734:Horse Diseases / Q000175:diagnosis / Q000188:drug therapy / Q000276:immunology*; D006736:Horses; D007074:Immunoglobulin G / Q000097:blood; D008297:Male; D013921:Thrombocytopenia / Q000175:diagnosis / Q000188:drug therapy / Q000276:immunology / Q000662:veterinary*
chemical_list: D001323:Autoantibodies; D005938:Glucocorticoids; D007074:Immunoglobulin G; D001379:Azathioprine