Gene transcription analysis in lesional skin of canine epitheliotropic cutaneous lymphoma using quantitative real-time RT-PCR.

Canine epitheliotropic cutaneous lymphoma (cECL) is characterized by infiltration of neoplastic lymphocytes in the skin with a specific tropism for the epidermis. Migration of lymphocytes is strictly controlled by interactions between chemokines and chemokine receptors, which may be involved in the pathogenesis of cECL. In this study, we investigated mRNA transcription levels of several chemokines (CCL17, CCL19, CCL21, CCL22, CCL27, CCL28 and CXCL10) and chemokine receptors (CCR4, CCR7, CCR10 and CXCR3) in lesional skin of cECL by quantitative real-time RT-PCR. To examine the subsets of accumulating neoplastic lymphocytes, we also investigated transcription levels of type-1 (IFN-γ, IL-12p35, IL-12p40 and LT-α) and type-2 (IL-4 and IL-13) cytokines and cytotoxic markers (perforin and granzyme B). We found that the lesional skin had higher mRNA transcription of CCL19, CXCL10, CCR4, CCR7, CCR10 and CXCR3 and lower transcription of CCL27 than healthy dog skin (p<0.05). In addition, transcription levels of type-1 cytokine and cytotoxic markers in lesional skin were significantly higher than those in healthy dog skin. These results indicate that the transcription of some chemokines and chemokine receptors, which are necessary for skin-homing, epitheliotropism and peripheral segregation of T-cells, is upregulated in the lesional skin of cECL. In addition, our results also indicate that the subset of neoplastic lymphocytes in cECL is most likely type-1 cytotoxic T-cells.