title: Tolerance signatures in transplant recipients.
abstract: OBJECTIVE
  The intent of this review was to describe biomarkers that predict or identify individuals who exhibit tolerance to a transplanted organ. The identification of tolerance biomarkers would spare some individuals the toxicity of immunosuppressive agents, enhance the safety of studies to induce tolerance, and provide insights into mechanisms of tolerance that may aid in designing new regimens.
  
  
  RESULTS
  Studies of tolerant kidney transplant recipients have revealed an association with B cells. More recent studies have suggested that these B cells may be less mature than from those in nontolerant recipients, and especially suited to suppress alloimmune responses. Biomarkers in tolerant liver transplant patients appear to be distinct from those associated renal tolerance. Most reports have identified an association with natural killer and/or γδ T cells rather than B cells. Recent data indicate biomarkers associated with iron homeostasis within the transplanted liver more accurately predict the tolerant state than do biomarkers expressed in the blood, suggesting that the renal allograft itself, which is infrequently sampled, would be informative.
  
  
  CONCLUSIONS
  Given the encouraging progress in identifying tolerance biomarkers, it will be important to validate these markers in larger studies of transplant recipients undergoing prospective minimization or withdrawal of immunosuppression.
authors.affiliation: aDepartment of Surgery, Emory University, Atlanta, Georgia bDepartment of Surgery and Immune Tolerance Network, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Kenneth A
authors.initials: KA
authors.lastname: Newell
authors.forename: Laurence A
authors.initials: LA
authors.lastname: Turka
mesh_terms: D001402:B-Lymphocytes / Q000276:immunology; D015415:Biomarkers / Q000097:blood; D006801:Humans; D007108:Immune Tolerance; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D016030:Kidney Transplantation; D016031:Liver Transplantation; D013601:T-Lymphocytes / Q000276:immunology
chemical_list: D015415:Biomarkers; D007166:Immunosuppressive Agents