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.
Lavergne
Sidonie N
SN
School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin 53706-1102, USA.
Trepanier
Lauren A
LA
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