Gastrin-Secreting Pancreatic Endocrine Tumor in a Dog (Putative Zollinger-Ellison Syndrome)

phase the islet infiltrates consist primarily of CD8positive/ CD4-negative cells and fewer CD4-positive/CD8-negative T lymphocytes. 2,13 In this cat, immunostaining demonstrated that most of the infiltrating cells were T lymphocytes (i.e., CD3 and CD5 positive). More specific identification of the infiltrates as CD8-positive/CD4-negative cytotoxic T cells, which may have been specific effecters against insulin-producing ß cells, was not possible with the antibodies and the formalin-fixed tissue available to us. The lesions in this cat suggest that islet infiltrates and immune-mediated destruction of islet cells may occur in and could contribute to development of diabetes mellitus in some cats. Viral infections may contribute in a complex way to development of autoimmune ß-cell destruction in humans and some nondomestic animals. This cat tested negative for feline leukemia virus but was not evaluated for feline infectious peritonitis virus or feline immunodeficiency virus infection. Acknowledgement. We thank Margaret Jones (Leukemia Research Fund Immunodiagnostic Unit, John Radcliffe Hospital, Oxford OX3 9DU, UK) for her generous donation of the leukocyte marker antibodies mb-1, B29, CD3, and CD5.