Gene expression analysis of Canine Demodicosis; A milieu promoting immune tolerance.

Canine demodicosis is a common skin disease seen in companion animal practice that results from an overpopulation of the commensal Demodex mite species. Common predisposing factors to the development of canine demodicosis include immunosuppressive diseases, such as neoplasia and hypothyroidism, and administration of immunosuppressive therapies, such as corticosteroids. Despite this, the pathogenesis of development of canine demodicosis remains unclear. Previous studies have implicated a role for increased expression of toll like receptor 2 (TLR2), increased production of interleukin (IL)-10) and T cell exhaustion. Here, we investigate gene expression of formalin fixed paraffin embedded skin samples from twelve cases of canine demodicosis in comparison to twelve healthy controls, using a 770 gene panel (NanoString Canine IO Panel). Results show an increase in the T cell population, specifically Th1 and Treg cells in dogs with demodicosis. In addition, while there is an upregulation of immunosuppressive cytokines such as IL-10 and IL-13, there is also an upregulation of immune check point molecules including PD-1/PD-L1 and CTLA-4. These findings suggest that Demodex spp. mites are modulating the host immune system to their advantage through upregulation of several immune tolerance promoting pathways.

MUM-1 in canine lymphoma: A pilot study.

Expression of interferon regulatory factor 4 (IRF4)/multiple myeloma oncogene-1 (MUM1) in peripheral T-cell lymphoma (PTCL) in people is associated with a poorer survival outcome compared to cases of PTCL lacking MUM1 expression. The aim of this study was to determine whether MUM1 is expressed in canine peripheral T-cell lymphoma not otherwise specified (PTCL-NOS). For comparison, the presence of MUM1 antigen was also investigated in canine diffuse large B cell lymphoma (DLBCL). Nine cases of PTCL-NOS and 9 cases of DLBCL diagnosed by a commercial veterinary diagnostic laboratory were selected. Positive immunohistochemical labeling for MUM1 was observed in PTCL-NOS (2 out of 9 cases) and DLBCL (3 out of 9 cases). These findings suggest that a subset of neoplastic T and B lymphocytes can express MUM1. The role of MUM1 in the biological behavior and outcome of canine lymphoma (CL) requires further investigation on a larger number of cases.