Cytokine and transcription factor expression by Aspergillus fumigatus-stimulated peripheral blood mononuclear cells in dogs with sino-nasal aspergillosis.

The causal agent of sino-nasal aspergillosis is usually Aspergillus fumigatus, which is a saprophytic and ubiquitous fungus that causes a severe rhinosinusitis in apparent healthy dogs. Affected dogs do not have systemic immuno-suppression. It has been shown previously that dogs affected by this disease have local over-expression of interleukin (IL)-10 and Th1 cytokines in nasal mucosal tissue. The aim of the present study was to assess the response of peripheral blood mononuclear cells (PBMC) from affected and unaffected dogs to antigen-specific stimulation with heat-inactivated Aspergillus spp. conidia, by quantifying gene expression for specific Th1, Th2, Th17 and Treg cytokines and their related transcription factors. Quantification of IL-4 and IFN-γ protein in culture supernatant was performed by enzyme-linked immunosorbent assay (ELISA). PBMC from dogs with SNA produced adequate mRNA encoding IFN-γ and IFN-γ protein. The expression of IL-17A mRNA was significantly greater in PBMC of affected compared with unaffected dogs. The amount of IL-10 mRNA in PBMC from affected dogs decreased after antigen-specific challenge. These results suggest that the incapacity of affected dogs to clear these fungal infections is not related to a defect in Th1 immunity or to an overwhelming regulatory reaction, but rather to an uncontrolled pro-inflammatory reaction driven by Th17 cells.

An immunohistochemical study of the inflammatory infiltrate associated with nasal carcinoma in dogs and cats.

The aims of this study were to characterize the inflammatory infiltrate associated with nasal carcinoma in dogs and cats and to determine whether this differed between the two species or with different types of carcinoma. Sections from fixed tissue biopsy samples of intranasal carcinoma from 31 dogs and six cats were labelled immunohistochemically to detect expression of the T-lymphocyte marker CD3, class II molecules of the major histocompatibility complex (MHC II), the myelomonocytic antigen MAC387 and immunoglobulin (Ig) G, IgA and IgM within the cytoplasm of plasma cells. All canine carcinomas were heavily infiltrated by MAC387(+) neutrophils, with smaller numbers of MAC387(+) macrophages. T cells were particularly prominent in the infiltrate associated with transitional carcinoma, and in such tumours were frequently mixed with MHC II(+) cells having macrophage or dendritic cell morphology. IgG(+) and IgA(+) plasma cells were detected at the peripheral margins of all types of canine carcinoma. In contrast, feline intranasal carcinoma was invariably associated with a marked infiltration of CD3(+) T cells. The feline tumour infiltrates contained sparse neutrophils and macrophages and few IgG(+) and IgA(+) plasma cells. These findings suggest that qualitatively different immune responses are induced in response to specific types of canine intranasal carcinoma, and that the canine and feline immune response to these neoplasms is also distinct.