The low CD25 and MHC class II surface expression in canine CD4+ PTCL observed by flow cytometry was corroborated by our gene expression data, which found that canine CD4+ PTCL had significantly decreased expression of IL2RA and MHC class II-associated genes compared to control canine CD4+ lymphocytes (Fig. 5A). The gene discussed is CD4; the disease is mature T-cell and NK-cell non-Hodgkin lymphoma.