Effect of immunosuppressive drugs on cytokine production in canine whole blood stimulated with lipopolysaccharide or a combination of ionomycin and phorbol 12‐myristate 13‐acetate

A pharmacodynamic assay has been previously developed to monitor ciclosporin treatment in dogs by assessing inhibition of cytokine transcription after whole blood stimulation with 12‐myristate 13‐1 acetate and ionomycin (PMA/I). In this study, whole blood stimulation with either PMA/I or lipopolysaccharide (LPS) was used to assess the effect of multiple drugs (azathioprine, ciclosporin, mycophenolate, leflunomide and prednisone) after a 7‐day treatment course on production of cytokines measured with a multiplex assay in healthy dogs (n = 4 for each treatment). Interleukin‐10 (IL‐10), interferon gamma (IFN γ) and tumour necrosis factor alpha (TNF α) were significantly activated by PMA/I stimulation and IL‐6, IL‐10 and TNF α by LPS stimulation, in the absence of immunosuppressive drugs. After ciclosporin treatment, IL‐10, IFN γ and TNF α production was significantly reduced after stimulation with PMA/I compared to pre‐treatment. After prednisone treatment, TNF α production was significantly reduced after stimulation with PMA/I or LPS compared to pre‐treatment. No significant change was observed after treatment with azathioprine, leflunomide or mycophenolate. This methodology may be useful to monitor dogs not only treated with ciclosporin, but also with prednisone or a combination of both. Further studies are needed to assess the use of this assay in a clinical setting.