Synergistic effects of CTLA-4Ig and sirolimus on orthotopic lung-allograft survival and histology

Academic Article


  • Background and Aims. The combination of CTLA-4Ig with sirolimus can promote indefinite survival in allograft models for which CTLA-4Ig monotherapy is ineffective. We sought to determine whether a limited course of CTLA-4Ig and sirolimus would alter survival of rat orthotopic single-lung transplantations. Methods. Left lungs of Brown Norway rats were transplanted into four groups of Lewis recipients (n=6 per group): group 1, no treatment; group 2, mCTLA-4Ig (250 μg/day for 4 days); group 3, sirolimus (3 mg/kg per day for 14 days); group 4, combined therapy with sirolimus and mCTLA-4Ig. Graft survival was determined by daily radiologic examination. Histologic grading of rejection and immunohistochemical staining for T and B lymphocytes were carried out at the time of radiologic graft loss. Results. Rejection of lung allografts in group 1 occurred at a median of 6.5 days. Neither sirolimus nor mCTLA-4Ig monotherapy resulted in significant prolongation of graft survival (median 9.5 and 8.0 days, respectively). Graft survival in group 4 was significantly prolonged compared with all other groups (median 29.5 days), and a significant reduction in histologic grade of rejection was observed following combination therapy compared with all other groups. Infiltration by CD8+ve T cells at the time of rejection was proportionately greater than CD4+ve T-cell infiltration for groups 1, 2, and 3 but not for the combined-therapy group. Conclusions. A brief course of combined mCTLA-4Ig and sirolimus prolongs graft survival, reduces severity of rejection, and attenuates CD8+ve T-cell infiltration of fully major histocompatibility complex mismatched lung allografts.
  • Published In

  • Transplantation  Journal
  • Digital Object Identifier (doi)

    Pubmed Id

  • 10678487
  • Author List

  • Ugurlu MM; Griffin MD; Tazelaar HD; McGregor CGA
  • Start Page

  • 489
  • End Page

  • 495
  • Volume

  • 76
  • Issue

  • 3