A Morphometric Study of Bone Marrow Megakaryocytes in Foals Infected with Equine Infectious Anemia Virus
| Autor: | Timothy B. Crawford, E. Reilich, Timothy V. Baszler, K. J. Wardrop |
|---|---|
| Rok vydání: | 1996 |
| Předmět: |
0301 basic medicine
Pathology medicine.medical_specialty 040301 veterinary sciences Anemia animal diseases Cell Count 0403 veterinary science Equine infectious anemia 03 medical and health sciences Megakaryocyte Bone Marrow medicine Animals Platelet Horses Cell Size Megakaryocytopoiesis Severe combined immunodeficiency General Veterinary biology 04 agricultural and veterinary sciences medicine.disease biology.organism_classification Thrombocytopenia Equine Infectious Anemia 030104 developmental biology medicine.anatomical_structure Immunology Lentivirus Female Severe Combined Immunodeficiency Bone marrow Megakaryocytes |
| Zdroj: | Veterinary Pathology. 33:222-227 |
| ISSN: | 1544-2217 0300-9858 |
| Popis: | Morphometric evaluation of bone marrow core biopsies was used to determine megakaryocyte (MK) numbers and MK size in nine foals with equine infectious anemia virus (E1AV)-induced thrombocytopenia. Both immunocompetent normal foals and foals with severe combined immunodeficiency (SCID) were used. Platelet counts were made three times weekly following viral infection. Bone marrow core biopsies were taken from the ilium of each foal prior to experimental infection, immediately after the onset of thrombocytopenia, and at necropsy. All foals developed thrombocytopenia by 23 days postinfection. The bone marrow MK density did not change in response to the thrombocytopenia. MK area did not change significantly; however, the MK nuclear area at necropsy was significantly higher than that preinfection. The presence of thrombocytopenia in the SCID foals showed that immune-specific responses were not required for the production of EIAV-induced thrombocytopenia. Furthermore, the lack of a compensatory megakaryocytopoiesis in both SCID and normal foals was consistent with the theory that altered platelet production plays a role in the development of this thrombocytopenia. The equine infectious anemia virus (EIAV) is a len- tivirus of the family Retroviridae. The virus shares homology with the human immunodeficiency virus types 1 and 2 (HIV-1 and HIV-2).6J1J2 Infection of horses with EIAV results in a persistent viremia and recurrent episodes of anemia, thrombocytopenia, and fever.I6 Previous studies have shown that the anemia is caused by both erythroid suppression and immune- mediated erythrocyte de~tr~ction.~~-~ ~~~~-~~~~~ The mech- anism of the thrombocytopenia is less clearly under- stood. Platelet-associated immunoglobulins G and M increase following expenmental infection of horses with EIAV, suggesting an immune-mediated destruction of platelets.'j Thrombocytopenia is also a common com- plication of infection with HIV and is often accom- panied by increased levels of platelet-associated anti- body.lJs In addition, a moderate reduction in platelet survival, decreased platelet production, morphologic abnormalities of megakaryocytes (MKs) and decreased numbers of MK progenitors in marrow culture have been demonstrated in HIV patients with thrombocy- topenia. 1,2,32,34,36,39 Recently, our laboratory initiated a study designed to further elucidate the mechanism(s) responsible for the thrombocytopenia of EIAV. Plate- let counts, platelet lifespans, and platelet production (via metabolic labeling of MKs) were determined in both immunologically normal and immunodeficient foals, with results suggesting that the thrombocyto- penia of EIAV infection may be at least in part non- immune mediated (T. B. Crawford, personal com- munication). The purpose of the study reported here was to further investigate EIAV-induced alterations in platelet production, by quantitating and sizing bone marrow MKs in EIAV-infected thrombocytopenic foals. |
| Databáze: | OpenAIRE |
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