FOXP3⁺ Treg frequency is no higher in canine B cell lymphoma than control samples.

<p>The frequency of FOXP3⁺ cells in fine needle aspirates harvested from the lymph nodes of dogs with B cell lymphoma (BCL), T cell lymphoma (TCL), reactive hyperplasia (RH) and mast cell tumors (MCT) is shown, expressed as a proportion of all cells (A, B, showing the effect of neoplastic effacement of normal lymphoid tissue; p = 0.00005), gated CD5⁺ cells (C, showing the resident T cells; p = 0.41), or sequentially gated CD5⁺ and then CD4⁺ T cells (D, showing specifically the resident CD4⁺ T cells; p = 0.74). Representative dot plots are shown for each of the groups, followed by box-and-whisker plots summarising the data. In each of the dot plots, the respective isotype control stain is shown above the specific stain. In this and subsequent figures, red symbols correspond to data from dogs ‘pre-treated’ with corticosteroids or any chemotherapeutic drug within three weeks of sampling. In the case of RH cases, square symbols (□) represent data from dogs with dermatitis; diamonds (◊) represent data from dogs with distant neoplasia; triangles (Δ) represent data from dogs with immune-mediated disease; and inverted triangles (▾) represent data from dogs with systemic infection. The expression of FOXP3 by PBMCs (E; p = 0.21) or by the CD5⁺ (F; p = 0.53) or specific CD5⁺CD4⁺ (G; p = 0.15) T cells within PBMCs similarly showed no differences between groups.