Accumulation of CD4⁺T cells in the colon of CsA-treated mice following myeloablative conditioning and bone marrow transplantation

Abstract

Syngeneic graft vs. host disease (SGVHD) was first described as a graft vs. host disease-like syndrome that developed in rats following syngeneic bone marrow transplantation (BMT) and cyclosporin A (CsA) treatment. SGVHD can be induced by reconstitution of lethally irradiated mice with syngeneic bone marrow cells followed by 21 days of treatment with the immunosuppressive agent CsA. Clinical symptoms of the disease appear 2–3 wk following cessation of CsA therapy, and disease-associated inflammation occurs primarily in the colon and liver. CD4+T cells have been shown to play an important role in the inflammatory response observed in the gut of SGVHD mice. Time-course studies revealed a significant increase in migration of CD4+T cells into the colon during CsA therapy, as well as significantly elevated mRNA levels of TNF-α, proinflammatory chemokines, and cell adhesion molecules in colonic tissue of CsA-treated animals compared with BMT controls, as early as day 14 post-BMT. Homing studies revealed a greater migration of labeled CD4+T cells into the gut of CsA-treated mice at day 21 post-BMT than control animals via CsA-induced upregulation of mucosal addressin cell adhesion molecule. This study demonstrates that, during the 21 days of immunosuppressive therapy, functional mechanisms are in place that result in increased homing of CD4+T effector cells to colons of CsA-treated mice.

Role of Oxidative Stress in the Colonic Complications of Murine Syngeneic Graft-versus-host Disease

“…Reactive nitrogen species were also elevated in the CsA treated animals compared to their control counterparts. Along with increases in oxidative stress, our group has shown increased levels of TNF-α and cellular adhesion molecules (CAM) in the colons of CsA treated mice compared to control BMT at early time points during and after CsA therapy [40]. The SGVHD induction regimen can trigger oxidative stress in many cell types and reports show that pathological changes associated with TNF-α signaling is associated with increased oxidative stress [41,42].…”