Myelogenous leukemia in adult inbred MHC-defined miniature swine: A model for human myeloid leukemias

This manuscript reports on five cases of spontaneous myelogenous leukemia, similar to human disease, occurring within highly inbred, histocompatible sublines of Massachusetts General Hospital (MGH) MHC-defined miniature swine. In cases where a neoplasm was suspected based on clinical observations, samples were obtained for complete blood count, peripheral blood smear, and flow cytometric analysis. Animals confirmed to have neoplasms were euthanized and underwent necropsy. Histological samples were obtained from abnormal tissues and suspect lesions. The phenotype of the malignancies was assessed by flow cytometric analysis of processed peripheral blood mononuclear cells and affected tissues. Five cases of spontaneous myeloid leukemia were identified in adult animals older than 30 months of age. All animals presented with symptoms of weight loss, lethargy, and marked leukocytosis. At autopsy, all animals had systemic disease involvement and presented with severe hepatosplenomegaly. Three of the five myelogenous leukemias have successfully been expanded in vitro. The clustered incidence of disease in this closed herd suggests that genetic factors may be contributing to disease development. Myelogenous leukemia cell lines established from inbred sublines of MGH MHC-defined miniature swine have the potential to be utilized as a model to evaluate therapies of human leukemia.