Anti-platelet antibodies in a natural animal model of sulphonamide-associated thrombocytopaenia.
Delayed hypersensitivity (HS) reactions to sulphonamide antimicrobials occur in both humans and dogs with a similar clinical presentation, and may include thrombocytopaenia. Drug-dependent anti-platelet antibodies have been identified in humans with sulphonamide-associated thrombocytopaenia. Our purpose was to determine whether similar antibodies were present in dogs with sulphonamide-associated thrombocytopaenia. Flow cytometry was used to detect anti-platelet antibodies in sera from 32 dogs with sulphonamide HS, eight dogs that tolerated sulphonamide therapy without adverse reactions and nine healthy control dogs were used as controls. Anti-platelet antibodies were found more frequently, with significantly stronger fluorescence signals, in HS dogs (75%) compared to 'tolerant' dogs (38%), and in HS dogs with thrombocytopaenia (90%) compared to HS dogs with normal platelet counts (46%). Binding to platelets was enhanced in the presence of soluble sulphonamide in 42% of positive samples. Experiments with canine Glanzmann's platelets, and competition assays with fibrinogen fragments or anti-GP antibodies, did not support the hypothesis that these canine antibodies target the fibrinogen receptor. In conclusion, anti-platelet antibodies were identified in dogs with sulphonamide-associated thrombocytopaenia, which suggests a similar immunopathogenesis for this reaction in dogs as seen in humans. Further work in both species will determine whether these antibodies are pathogenic in vitro.
School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin 53706-1102, USA.
Sidonie N
SN
Lavergne
Lauren A
LA
Trepanier
D000818:Animals; D001323:Autoantibodies / Q000097:blood*; D001792:Blood Platelets / Q000276:immunology*; D004285:Dogs; D004342:Drug Hypersensitivity; D005434:Flow Cytometry; D023421:Models, Animal; D013449:Sulfonamides / Q000009:adverse effects*; D013921:Thrombocytopenia / Q000139:chemically induced* / Q000276:immunology
D001323:Autoantibodies; D013449:Sulfonamides