An Immunocytochemical Study of Lymphohistiocytic Disorders in the Dog

Artuffo, Mara Carla (1995) An Immunocytochemical Study of Lymphohistiocytic Disorders in the Dog. PhD thesis, University of Glasgow.

Abstract

This thesis is a study of the application of monoclonal leukocyte antibodies to cutaneous lympho-histiocytic disorders in the dog. Monoclonal antibodies have been widely applied to studies in mam and rodents, but until recently the utilization of monoclonal antibodies in the dog has been restricted to a very small number of markers. In the past few years, some antibodies directed against human leukocyte antigens and antibodies raised against internal peptide sequences in human and murine leukocytes have been shown to cross-react with canine tissue. In addition, monoclonal leukocyte antibodies specifically raised against canine leukocyte antigens have been produced and assigned to Clusters of Differentiation corresponding to the human classification. Some anti-human and anti-mouse monoclonal antibodies, as well as a number of canine monoclonal antibodies, have been utilised for flow cytometric analysis. In Section I, Chapter 1, the literature on leukocyte surface markers and the immune system in general is reviewed and in Chapter 2 the materials and methods are detailed. Investigations on normal canine cells are described in Section n. A total of twenty monoclonal leukocyte antibodies, 15 anti-canine and 5 anti-canine leukocyte antibodies, were available for use on canine tissue. Seven of the anti-canine markers were unsuitable in the Glasgow University Veterinary School immunohistochemistry system and were excluded from further studies. The remaining 13 monoclonal leukocyte markers were verified on normal canine tissue and a normal staining pattern was identified for each marker as reported in Chapter 3. These markers constituted Panel 1. Three of these markers (THY-1, CD4 and CD8?) together with two additional B-cell markers (CVS31 and CVS32) constituted Panel 2 which was used in flow cytometry as described in Chapter 4. A range of normal values was established for all five markers. The anti-canine antibodies were new antibodies presented in the Canine Leukocyte Antigen Workshop 1993, while the anti-human antibodies were known to cross-react with other animal species, but no data were available in the dog. The two panels of monoclonal antibodies were subsequently utilised for immunohistologic staining of paraneoplastic and neoplastic disorders (Section III), chronic cutaneous inflammation (Section IV) and an immunodeficiency disorder (Section V). Chapter 5 describes the application of leukocyte antibodies to samples from 19 dogs, mainly collies, affected by histiocytic dermatoses. A variety of these cutaneous disorders has been described in the dog as well as in man. Lesions can range from granulomatous inflammation, with predominantly a mixed cell population, to neoplasms, with a monocyte/macrophage lineage. In the dog, as in mem, these diseases are described as rare with the exception being cutaneous histioc3rtoma which is a common neoplasm of young dogs. Lesions from the 19 dogs available for this study were classified into three distinct groups on the basis of their different histological and immunohistological features. Samples from six dogs were classified as granulomatous inflammation. The infiltrate was composed of a variety of cells, the majority of which were positive for T- or B-cell markers, but macrophages and granulocytes staining positively for MAC387 and lysozyme were also present. No further immunophenotyping was carried out on these cells because CD4 and CD8alpha antibodies were effective only on ciyostat sections. Lesions from eight dogs, characterised by vasculopathy, vasculitis and a perivascular infiltrate were classified as lymphomatoid granulomatosis. Immunohistologically, the majority of the cells stained positively for CD3. Macrophages and granulocytes positive for MAC387 and lysozyme and B-cells, mainly positive for CD79a, were also found. Samples from five dogs were classified as histiocytosis on the basis of an infiltrate composed of mostly histiocytes with only a few lymphocytes and granulocytes. The lack of more specific macrophage/monocyte markers precluded the identification of a significant proportion of the large round cells present as part of the infiltrate of these histiocytic disorders. Lymphoma (Chapter 6) is one of the most common neoplasms in the dog; clinical signs and therapy have been widely discussed throughout the years. In comparison to studies of human lymphoma, few immunohistologic studies have been carried out to immunophenotype lymphomas in the dog. In this thesis, samples from 35 dogs with lymphoma and one dog with leukaemia were stained with leukocyte markers. The solid tumours were examples of either cutaneous (non-epitheliotropic and intraepithelial) or multicentric lymphoma. AU cases of epitheliotropic lymphoma/mycosis fungoides were positive for T-cell markers with the majority of the cells being CD8alpha+. The majority of the non- epitheliotropic lymphomas was also positive for T-cell markers, but CD4 was the main phenotype. Loss of CDS and CD45RA antigen was noted in all cutaneous lymphoma. Only one of the cutaneous, non-epitheliotropic lymphomas, was positive for B-cell markers. These findings confirmed that the majority of cutaneous lymphomas, in the dog, are of T-lineage as in man.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Additional Information: Adviser: Pauline McNeill
• Keywords: Veterinary science, Animal diseases
• Date of Award: 1995
• Depositing User: Enlighten Team
• Unique ID: glathesis:1995-75538
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 19 Nov 2019 19:32
• Last Modified: 19 Nov 2019 19:32
• URI: https://theses.gla.ac.uk/id/eprint/75538