Tofacitinib fails to prevent T cell transfer colitis in mice but ameliorates disease activity

Introduction: Tofactinib is a JAK inhibitor approved for ulcerative colitis in humans. Despite of its’ proven effectiveness in humans, mechanistic data are scarce on the effectiveness of Tofactinib in experimental colitis in mice. Methods: We induced experimental colitis by transfer of CD4 + CD25- isolated T cells into lymphopenic RAG2-/- mice and treated these mice with tofacitinib for 5–6 weeks either with a dosage of 10 or 40 mg/kg body weight immediately after CD4 + transfer or started treatment after first symptoms of disease for several weeks. Results: While treatment with tofacitinib immediately after transfer resulted in an enhanced expansion of CD4 + T cells and did not prevent occurrence of colitis, treatment after start of symptoms of colitis ameliorated disease activity on a clinical basis and in histological analyses. Discussion: Tofacitinib is effective in the treatment of murine experimental T cell transfer colitis, however does not prevent occurrence of disease.