Gene Expression in Biopsies of Acute Rejection and Interstitial Fibrosis/Tubular Atrophy Reveals Highly Shared Mechanisms That Correlate With Worse Long-Term Outcomes
B D Modena, S M Kurian, L W Gaber, J Waalen, A I Su, T Gelbart, T S Mondala, S R Head, S Papp, R Heilman, J J Friedewald, S M Flechner, C L Marsh, R S Sung, H Shidban, L Chan, M M Abecassis, D R Salomon, B D Modena, S M Kurian, L W Gaber, J Waalen, A I Su, T Gelbart, T S Mondala, S R Head, S Papp, R Heilman, J J Friedewald, S M Flechner, C L Marsh, R S Sung, H Shidban, L Chan, M M Abecassis, D R Salomon
Abstract
Interstitial fibrosis and tubular atrophy (IFTA) is found in approximately 25% of 1-year biopsies posttransplant. It is known that IFTA correlates with decreased graft survival when histological evidence of inflammation is present. Identifying the mechanistic etiology of IFTA is important to understanding why long-term graft survival has not changed as expected despite improved immunosuppression and dramatically reduced rates of clinical acute rejection (AR) (Services UDoHaH. http://www.ustransplant.org/annual_reports/current/509a_ki.htm). Gene expression profiles of 234 graft biopsy samples were obtained with matching clinical and outcome data. Eighty-one IFTA biopsies were divided into subphenotypes by degree of histological inflammation: IFTA with AR, IFTA with inflammation, and IFTA without inflammation. Samples with AR (n = 54) and normally functioning transplants (TX; n = 99) were used in comparisons. A novel analysis using gene coexpression networks revealed that all IFTA phenotypes were strongly enriched for dysregulated gene pathways and these were shared with the biopsy profiles of AR, including IFTA samples without histological evidence of inflammation. Thus, by molecular profiling we demonstrate that most IFTA samples have ongoing immune-mediated injury or chronic rejection that is more sensitively detected by gene expression profiling. These molecular biopsy profiles correlated with future graft loss in IFTA samples without inflammation.
Keywords: Interstitial fibrosis and tubular atrophy; basic (laboratory) research/science; genomics; graft survival; immunobiology; kidney (allograft) function/dysfunction; kidney transplantation/nephrology; organ transplantation in general; rejection: T cell mediated (TCMR); translational research/science.
Conflict of interest statement
Disclosure
The authors of this manuscript have conflicts of interest to disclose as described by the American Journal of Transplantation. D.R.S. and M.M.A. are the founding scientists of Transplant Genomics Inc. S.M.K. and S.R.H. have stock equity and receive consulting fees from TGI. T.G. is partially supported by salary funding from TGI to The Scripps Research Institute. The other authors have no conflicts of interest to disclose.
© Copyright 2016 The American Society of Transplantation and the American Society of Transplant Surgeons.
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Source: PubMed