Occurrence of primary lymphocytic hypophysitis in two horses and presence of scattered T-lymphocytes in the normal equine pituitary gland.
Abstract: The postmortem examination of a 14-y-old Appaloosa gelding with clinically diagnosed pituitary pars intermedia dysfunction showed a unique finding of moderate multifocal lymphocytic hypophysitis (LH). The pituitary glands of 24 horses submitted for postmortem examination were examined grossly and examined histologically for the presence of lymphocytes. Of these 23 horses, 1 additional case suffered from moderate LH. The 2 cases with LH tested negative for Equid herpesvirus 1 and 4 by polymerase chain reaction and immunohistochemistry (IHC), and no viral particles were observed by electron microscopy in 1 case examined. The cause of LH remains unknown, but based on the T-lymphocytic nature of the inflammation and the human literature, an immune-mediated origin is hypothesized. In addition, the review of 24 cases revealed that 10 horses had few and small multifocal lymphocytic infiltrates within the pituitary gland; the remaining 12 horses showed no evident lymphocytes when examined by hematoxylin and eosin. IHC for CD3 showed the presence of a small number of individual T-lymphocytes scattered through the gland in all examined horses, which appears therefore to be a normal feature of the pituitary gland in horses.
Publication Date: 2016-11-16 PubMed ID: 27852816DOI: 10.1177/1040638716676292Google Scholar: Lookup
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Summary
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The research examines the occurrence of a rare disease, lymphocytic hypophysitis (LH), in horses. The disease was found in two out of 24 specimens examined, its cause remains unknown but it may be immune-mediated. Interestingly, a small number of T-lymphocytes, which are usually related to immune responses, were found scattered throughout the pituitary gland of all horses examined, suggesting this might be a normal occurrence in horses.
Objective of the Study
- The purpose of the research was to understand the occurrence of lymphocytic hypophysitis (LH) in horses, an inflammation of the pituitary gland, which is often linked to disorders such as pituitary pars intermedia dysfunction.
Methodology
- Postmortem examinations were conducted on 24 horses, beginning with a 14-year-old Appaloosa gelding that showed signs of pituitary-related disorders.
- Detailed gross and microscopic examinations were carried out to detect the presence and extent of LH and to identify associated symptoms like the presence of lymphocytes, a type of white blood cell.
- Testing for Equid herpesvirus 1 and 4, known causes of pituitary diseases in horses, was also done via Polymerase Chain Reaction (a molecular biology technique) and immunohistochemistry (a process that uses antibodies to detect proteins in cell tissues).
Findings
- Out of 24 studied horses, moderate LH was found in two horses including the initial Appaloosa gelding.
- Both these horses tested negative for Equid herpesvirus 1 and 4, eliminating these viruses as potential causes for LH.
- Interestingly, a small number of individual T-lymphocytes were found scattered throughout the pituitary gland in all 24 horses. These cells are often associated with immune responses.
Interpretations & Conclusion
- The researchers hypothesized the cause of LH to be immune-mediated given the presence of scattered T-lymphocytes. However, the fact that these were found in all horses, even those without LH, suggested that this might be a normal feature of the equine pituitary gland.
- The exact cause of LH in horses remains unknown, necessitating further research in this area.
Cite This Article
APA
Grau-Roma L, Peckham R, Paton J, Stahel A, de Brot S.
(2016).
Occurrence of primary lymphocytic hypophysitis in two horses and presence of scattered T-lymphocytes in the normal equine pituitary gland.
J Vet Diagn Invest, 29(1), 115-121.
https://doi.org/10.1177/1040638716676292 Publication
Researcher Affiliations
- School of Veterinary Medicine and Sciences, University of Nottingham, Sutton Bonington Campus, Loughborough, UK (Grau-Roma, de Brot).
- University College Dublin, Equine Veterinary Hospital, University College Dublin Campus, Belfield, Dublin, Ireland (Peckham).
- Scarsdale Equine Veterinary Practice, Derby, UK (Paton).
- Institute of Virology, University of Zurich, Vetsuisse Faculty, Zurich, Switzerland (Stahel).
- School of Veterinary Medicine and Sciences, University of Nottingham, Sutton Bonington Campus, Loughborough, UK (Grau-Roma, de Brot).
- University College Dublin, Equine Veterinary Hospital, University College Dublin Campus, Belfield, Dublin, Ireland (Peckham).
- Scarsdale Equine Veterinary Practice, Derby, UK (Paton).
- Institute of Virology, University of Zurich, Vetsuisse Faculty, Zurich, Switzerland (Stahel).
- School of Veterinary Medicine and Sciences, University of Nottingham, Sutton Bonington Campus, Loughborough, UK (Grau-Roma, de Brot).
- University College Dublin, Equine Veterinary Hospital, University College Dublin Campus, Belfield, Dublin, Ireland (Peckham).
- Scarsdale Equine Veterinary Practice, Derby, UK (Paton).
- Institute of Virology, University of Zurich, Vetsuisse Faculty, Zurich, Switzerland (Stahel).
- School of Veterinary Medicine and Sciences, University of Nottingham, Sutton Bonington Campus, Loughborough, UK (Grau-Roma, de Brot).
- University College Dublin, Equine Veterinary Hospital, University College Dublin Campus, Belfield, Dublin, Ireland (Peckham).
- Scarsdale Equine Veterinary Practice, Derby, UK (Paton).
- Institute of Virology, University of Zurich, Vetsuisse Faculty, Zurich, Switzerland (Stahel).
- School of Veterinary Medicine and Sciences, University of Nottingham, Sutton Bonington Campus, Loughborough, UK (Grau-Roma, de Brot).
- University College Dublin, Equine Veterinary Hospital, University College Dublin Campus, Belfield, Dublin, Ireland (Peckham).
- Scarsdale Equine Veterinary Practice, Derby, UK (Paton).
- Institute of Virology, University of Zurich, Vetsuisse Faculty, Zurich, Switzerland (Stahel).
MeSH Terms
- Animals
- Diagnosis, Differential
- Herpesvirus 1, Equid / isolation & purification
- Herpesvirus 4, Equid / isolation & purification
- Horse Diseases / diagnosis
- Horse Diseases / pathology
- Horse Diseases / virology
- Horses
- Hypophysitis / diagnosis
- Hypophysitis / veterinary
- Immunohistochemistry / veterinary
- Male
- T-Lymphocytes / pathology
Citations
This article has been cited 1 times.- Frigerio ED, Guizelini CC, Jussiani GG, Março KS, de Melo GD, Watanabe TTN, Machado GF. Lymphocytic hypophysitis in dogs infected with Leishmania spp. Front Vet Sci 2023;10:1208919.
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