Immunophenotypic characterization of peripheral blast cells in a leukemic miniature pig

Association of Chronic Myelogenous (Basophilic) Leukemia and the BCR/ABL Mutation in a Yucatan Barrow (Sus scrofa domestica)

Background: Chronic myelogenous leukemia (CML) is a clonal proliferative disorder of the myeloid, megakaryocyte, and erythroid lineages. The onset and subsequent progression of CML is well-described in humans. There is comparably little information surrounding CML progression in veterinary species, including Yucatan miniature swine that are common for preclinical pharmaceutical and device testing. In humans, more than 90% of CML cases are associated with a chromosomal translocation that results in the Philadelphia gene (BCR/ABL mutation). In this report, the presence of the Philadelphia gene in a Yucatan burrow was confirmed in white blood cells collected prior to onset of clinical signs with primers designed from the human BCR/ABL sequence. Case Presentation: A 24 month old, 70 kg, Yucatan barrow received a prefabricated bovine cortical bone xenograft following a unilateral zygomatic ostectomy for a preclinical study. Complete blood count and serum chemistries were performed prior to and 28, 53, 106, and 129 days after facial surgery. Fifty three days after surgery, a bone marrow biopsy was performed due to anorexia, severe basophilia, and mild anemia. A finding of a moderate increase in basophilic precursors in bone marrow cytology was followed by lymphocyte immunophenotyping via flow cytometry and RT-PCR amplification of the Philadelphia gene in white blood cell samples from the affected barrow and an unaffected barrow in the same treatment group. Bone marrow, lymph node, liver, spleen, lung, kidney, and adrenal gland lesions of mostly myeloblasts were identified after the affected barrow died 146 days after surgery. Flow cytometry confirmed lymphopenia and suggested basophilia, and RT-PCR established the presence of the BCR/ABL gene. Conclusions: The information in this report confirms the presence of the BCR/ABL mutation and documents progression of chronic myelogenous (basophilic) leukemia from a chronic phase to a terminal blast crisis in an adult Yucatan barrow. The natural occurrence and progression of CML associated with the BCR/ABL mutation in miniature swine establishes potential for future porcine models of human CML. The information also establishes a genetic test to confirm porcine CML to prevent inadvertent attribution of clinical signs to treatment complications during preclinical testing.

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.

Minipigs and potbellied pigs as pets in the veterinary practice--a retrospective study

Minipigs have become popular pets in recent years. Therefore, an increasing number of veterinarians are being challenged by specific problems of these animals. This retrospective study gives an overview on the diagnoses and therapeutic interventions of the patients submitted to the clinic for swine at the University of Veterinary Medicine Vienna during the last 6 years (n=48). Most frequently, colic symptoms of the gastro-intestinal tract (n=12) and orthopaedic locomotion disorders (n=10), mainly due to accidents or long claws, could be observed, followed by urogenital tract and skin disorders (n=4 each). Therapeutic interventions are discussed with regard to medical aspects as well as statutory provisions.

Acute B-cell lymphoblastic leukaemia in a 5-month-old boar

CASE HISTORY

A 5-month-old mixed-breed boar presented with lethargy, weakness and anorexia of 1 week's duration.

CLINICAL FINDINGS AND DIAGNOSIS

The boar had an elevated heart rate, slow capillary refill time and cyanotic skin over the ears; it was also severely anaemic. A necropsy revealed scattered petechial haemorrhages, small subcapsular white nodules on the kidneys, a nodule in the parenchyma of one testis, creamy-white bone marrow, a preputial diverticulum, and an ulcer of the pars oesophagea of the stomach. Cytology of peripheral blood and bone marrow identified large numbers of lymphoblasts, which were demonstrated using immunocytochemistry to be of B-cell origin. Histological examination of multiple organs also showed lymphoblastic infiltration.

DIAGNOSIS

B-cell lymphoblastic leukaemia with secondary infiltration of lymphoid organs, kidneys, testis and preputial skin.

CLINICAL RELEVANCE

This is the fi rst known reported case of acute B-cell lymphoblastic leukaemia in swine.

Fibroepithelial hamartoma in a domestic pig

This case report is the first description of a fibroepithelial hamartoma in a pig. The dysplasia, which covered half of the face of the newborn piglet, did not increase in relative size until the animal was euthanatized at 6 months of age. Histologic examination revealed a moderate orthokeratotic hyperkeratosis with variable degrees of epithelial proliferation. The main body of the dysplasia consisted of collagenous fibers. In addition, some proliferating small blood vessels as well as focally gathered dilated apocrine glands were evident. Given morphologic and clinical features, the diagnosis of a hamartoma seemed to be justified.