Evaluation of immunologic parameters in canine glioma patients treated with an oncolytic herpes virus

AIM

To molecularly characterize the tumor microenvironment and evaluate immunologic parameters in canine glioma patients before and after treatment with oncolytic human IL-12-expressing herpes simplex virus (M032) and in treatment naïve canine gliomas.

METHODS

We assessed pet dogs with sporadically occurring gliomas enrolled in Stage 1 of a veterinary clinical trial that was designed to establish the safety of intratumoral oncoviral therapy with M032, a genetically modified oncolytic herpes simplex virus. Specimens from dogs in the trial and dogs not enrolled in the trial were evaluated with immunohistochemistry, NanoString, Luminex cytokine profiling, and multi-parameter flow cytometry.

RESULTS

Treatment-naive canine glioma microenvironment had enrichment of Iba1 positive macrophages and minimal numbers of T and B cells, consistent with previous studies identifying these tumors as immunologically "cold". NanoString mRNA profiling revealed enrichment for tumor intrinsic pathways consistent with suppression of tumor-specific immunity and support of tumor progression. Oncolytic viral treatment induced an intratumoral mRNA transcription signature of tumor-specific immune responses in 83% (5/6) of canine glioma patients. Changes included mRNA signatures corresponding with interferon signaling, lymphoid and myeloid cell activation, recruitment, and T and B cell immunity. Multiplexed protein analysis identified a subset of oligodendroglioma subjects with increased concentrations of IL-2, IL-7, IL-6, IL-10, IL-15, TNFα, GM-CSF between 14 and 28 days after treatment, with evidence of CD4⁺ T cell activation and modulation of IL-4 and IFNγ production in CD4⁺ and CD8⁺ T cells isolated from peripheral blood.

CONCLUSION

These findings indicate that M032 modulates the tumor-immune microenvironment in the canine glioma model.

Cutaneous Pilomatrical Carcinosarcoma in a Dog

Malignant pilomatricomas are uncommon cutaneous neoplasms in veterinary and human medicine. Pilomatrical carcinosarcoma is a rare subset of malignant pilomatricoma that has been described in man. This article reports a neoplasm with morphological features of pilomatrical carcinosarcoma in a dog. The nodular neoplasm occurred on the left lateral hock and was partially alopecic. Microscopically, the tumour was composed of a cystic carcinomatous component surrounding areas of abrupt keratinization and a sarcomatous component exhibiting bundles of spindle cells and irregular, scalloped areas of mineralized and non-mineralized osteoid matrix. The carcinomatous and sarcomatous areas were immunoreactive for pan-cytokeratin and vimentin, respectively, while immunoreactivity for e-cadherin was restricted to the carcinomatous component of the neoplasm. The unique morphological features of this tumour were similar to those described in human pilomatrical carcinosarcoma.

Diffuse Infiltrative Colonic Lipomatosis in a Vietnamese Pot-bellied Pig

Diffuse infiltrative gastrointestinal lipomatosis (DIGIL) is characterized by widespread proliferation of adipose tissue within the submucosal and subserosal layers of the gastrointestinal tract. Here we describe a case of diffuse infiltrative colonic lipomatosis in a 3-year-old male Vietnamese pot-bellied pig. Gross anatomical changes included obesity with sparse small intestinal contents and no colonic contents. The colonic lumen was narrowed and the colonic wall was diffusely thickened (∼5 mm), white, homogeneous and soft. Other findings were vesical uroliths and mild fibrinous pneumonia. Histologically, the colonic submucosa and muscle layers were expanded and almost completely replaced by sheets of adipose tissue admixed with scant fibrovascular tissue. Other minor changes included mild fibrinous pneumonia, splenic lymphoid depletion and testicular atrophy. The colonic changes in the current case are consistent with those described for DIGIL. This is a rare condition in human beings and animals and has never been described in pigs.

Neuropathology of Natural Cytauxzoon felis Infection in Domestic Cats

Cytauxzoonosis is a tick-borne disease of felids caused by the protozoan Cytauxzoon felis. This article characterizes the neuropathologic changes in 8 cases of natural C. felis infection in domestic cats with typical clinical signs and pathologic changes in multiple organs. Histologic changes in the brain included intravascular schizont-laden macrophages in leptomeningeal and parenchymal arterioles and venules. Small capillaries throughout the gray and white matter and choroid plexus also appeared occluded. Affected vessels were often surrounded by small to moderate numbers of lymphocytes and plasma cells and multiple areas of hemorrhage. Vasculitis and fibrin thrombi were occasionally present. Parenchymal changes consisted of variable degrees of vacuolation of the gray and white matter, with microgliosis, astrocytosis, astrogliosis, and multiple microhemorrhages. Multiple well-demarcated areas of necrosis observed in 4 cases were characterized by marked vacuolation of the gray or white matter, with necrotic neurons containing shrunken hypereosinophilic cytoplasm and pyknotic nuclei, nuclear debris, swollen axons, and scattered foamy macrophages. The changes in the brains of affected cats were attributed to vascular occlusion and secondary ischemia caused by the protozoal infection.

Paraparesis in a Golden Retriever

A 7-year-old female spayed Golden Retriever dog presented with fever and a 10-day history of neurological signs, including ambulatory paraparesis and pelvic limb ataxia. Neurological examination initially revealed a T3-L3 myelopathy. Thoracic radiographs revealed a diffuse miliary pulmonary pattern. Endotracheal washes and fine-needle aspirates from several organs aimed at identifying a potential infectious agent or neoplastic process were all unsuccessful. Due to worsening of the clinical signs, euthanasia was elected. Necropsy findings included multifocal, pale to dark red, firm nodules infiltrating the lungs, heart, mesentery, pancreas, small intestine, brain, and spinal cord. Cytological examination of impression smears obtained from the pulmonary nodules during necropsy revealed clusters of epithelioid cells admixed with fewer spindle cells, erythrocytes, and scattered leukocytes. Clinical signs and cytological findings initially suggested the possibility of a widespread granulomatous disease or a metastatic epithelial neoplasm as possible clinical differentials in this case. The final diagnosis was based on the gross and histological findings, with confirmation following histochemistry and immunohistochemistry.

High-pathogenicity avian influenza virus in the reproductive tract of chickens

Infection with high-pathogenicity avian influenza virus (HPAIV) has been associated with a wide range of clinical manifestations in poultry, including severe depression in egg production and isolation of HPAIV from eggs laid by infected hens. To evaluate the pathobiology in the reproductive tract of chickens, adult hens were inoculated intranasally with 3 HPAIV strains. All 3 strains induced lesions in the reproductive tract 36 to 72 hours after inoculation. Positive immunostaining was observed in all segments of the reproductive tract, occurring predominantly in stromal cells and superficial germinal epithelium of the ovary, in mucosal epithelial cells and less often glandular epithelium throughout the oviduct, and in vascular endothelium. This study generates important data and explains previously reported virus isolation from yolk, due to ovarian virus replication, and virus recovery from albumin, due to virus replication in epithelial cells in several segments of the oviduct.

Diagnostic exercise: suppurative rhombencephalitis and meningitis in a goat

A 1-year-old female Boer goat was presented for necropsy following spontaneous death and history of acute recumbency, nystagmus, and sialorrhea. A swollen area was grossly observed in the brainstem at the level of the pons. On cut surface, the right cerebellar peduncles were expanded by a focal, pale, poorly demarcated, slightly depressed, and soft area of malacia. Microscopically, this area contained diffuse edema and necrosis, with microabscesses, neuronal necrosis, neuronophagia, axonal spheroids, vasculitis, and perivascular accumulations of lymphocytes, plasma cells, macrophages, and neutrophils. The diagnosis was based on the morphologic findings, fluorescent antibody test results, and special staining.

Necrotizing Meningoencephalitis in a Cow

An 18-month-old Charolais cow developed depression and drooling and was submitted for necropsy after euthanasia. The cow was 1 of 50 moved between 2 farms approximately 5 days before the onset of clinical disease. Gross findings included swollen and hemorrhagic areas of malacia in the frontal, temporal, and parietal lobes of the cerebral cortex. Microscopically there was a necrotizing meningoencephalitis with intranuclear astrocytic and neuronal eosinophilic viral inclusions in the frontal, temporal, and parietal cerebral cortex as well as in the basal nuclei and thalamus. The gross and microscopic findings were consistent with necrotizing meningoencephalitis caused by bovine herpesvirus (BHV-1 or BHV-5), and the diagnosis was confirmed by detection of bovine herpesviral antigen on fresh samples of brain via fluorescent antibody test using a monoclonal antibody against BHV-1 glycoprotein C.