Procoagulant Microparticles in Dogs with Immune‐Mediated Hemolytic Anemia |
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Authors: | L Kidd J Geddings Y Hisada M Sueda T Concannon T Nichols E Merricks N Mackman |
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Institution: | 1. Western University of Health Sciences College of Veterinary Medicine, Pomona, CA;2. Division of Hematology/Oncology, Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC;3. California Veterinary Specialists, Ontario, CA;4. Francis Owen Blood Research Laboratory Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC |
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Abstract: | BackgroundStudies of some human prothrombotic diseases suggest that phosphatidylserine‐positive (PS+) and tissue factor‐positive (TF+) microparticles (MPs) might play a role in the pathogenesis of thrombosis or serve as biomarkers of thrombotic risk.Hypothesis/ObjectivesTo determine if circulating levels of PS+MP and procoagulant activity (PCA) associated with PS+MPs and TF+ MPs are increased in dogs with IMHA.AnimalsFifteen dogs with primary or secondary IMHA and 17 clinically healthy dogs.MethodsProspective case‐controlled observational study. Circulating PS+MPs were measured by flow cytometry. PCA associated with PS+MPs and TF+MPs was measured by thrombin and Factor Xa generating assays, respectively.ResultsCirculating numbers of PS+MPs were not significantly higher in dogs with IMHA control median 251,000/μL (36,992–1,141,250/μL); IMHA median 361,990/μL (21,766–47,650,600/μL) P = .30]. However, PS+MP PCA control median 2.2 (0.0–16.8) nM PS eq; IMHA median 8.596, (0–49.33 nM PS eq) P = .01] and TF+MP PCA control median 0.0, (0.0–0.0 pg/mL); IMHA median 0.0; (0–22.34 pg/mL], P = .04) were increased. Intravascular hemolysis, which we showed might increase PS+ and TF+MP PCA, was evident in 3 of 5 dogs with PS+MP PCA and 2 of 4 dogs with TF+MP PCA higher than controls. Underlying disease in addition to IMHA was detected in 1 of 5 dogs with PS+PCA and 3 of 4 dogs with TF+MP PCA higher than controls.Conclusions and Clinical Importance
TF+ and PS+MP PCA is increased in some dogs with IMHA. Further studies that determine if measuring TF+ and PS+ MP PCA can help identify dogs at risk for thrombosis are warranted. |
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Keywords: | Auto‐immune hemolytic anemia Hemolysis Microvesicle Phosphatidylserine Procoagulant Tissue factor |
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