Neonatal alloimmune thrombocytopenia in a quarter horse foal

J Vet Intern Med. 1997 Sep-Oct;11(5):304-8. doi: 10.1111/j.1939-1676.1997.tb00470.x.


Neonatal alloimmune thrombocytopenia is recognized as a spontaneous disease of human infants, piglets, and possibly mules, but it has not been previously reported in horses. A 1-day-old Quarter Horse foal presented to Michigan State University Large Animal Clinic with severe thrombocytopenia of unknown origin. Immunoglobulins that bound to the foal's platelets were identified in the mare's plasma, serum, and milk by indirect assays. The immunoglobulins were further shown to recognize platelets from the foal's full brother, born 1 year earlier. These findings, coupled with the clinical course of the foal during its period of hospitalization, strongly suggest that neonatal alloimmune thrombocytopenia can spontaneously occur in neonatal horses. This diagnosis should be considered for foals with severe thrombocytopenia when other causes can be excluded, and platelet antibody assays should be used to support this diagnosis.

Publication types

  • Case Reports

MeSH terms

  • Animals
  • Animals, Newborn
  • Antibodies / analysis
  • Blood Cell Count / veterinary
  • Blood Platelets / immunology
  • Blood Proteins / analysis
  • Fibrinogen / analysis
  • Hematocrit / veterinary
  • Hemoglobins / analysis
  • Horse Diseases / blood
  • Horse Diseases / diagnosis*
  • Horse Diseases / immunology
  • Horses
  • Immunoglobulins / blood
  • Immunoradiometric Assay / methods
  • Immunoradiometric Assay / veterinary
  • Male
  • Partial Thromboplastin Time / veterinary
  • Platelet Count / veterinary
  • Thrombocytopenia / diagnosis
  • Thrombocytopenia / immunology
  • Thrombocytopenia / veterinary*


  • Antibodies
  • Blood Proteins
  • Hemoglobins
  • Immunoglobulins
  • Fibrinogen