What can we learn from the transcriptional characterization of spontaneously tolerant transplant recipients?

Purpose of review Even if improvements of immunosuppressive treatments enabled to prevent acute rejection in solid organ transplantation, current immunosuppressive regimens are implicated in long-term side effects without the resolution of chronic rejection. Thus, during last years, research focused mainly on immunosuppression weaning off studies based on individualized follow-up of patients. Beyond animal models, studies have been emphasized by descriptions of a particular group of transplant patients displaying an operational tolerance in the absence of immunosuppressive treatments. Herein we will review recent advances in transcriptional characterization of spontaneously tolerant transplant recipients. Recent findings Transcriptomic profiling in the blood of these so-called 'operationally tolerant' patients succeeded to establish tolerance footprint that could be used to detect a tolerance profile among transplanted patients under immunosuppression, in order to adapt their treatment and eventually wean off them. Summary The advent of this field raise questions about how to blend and cross transcriptomic studies in the different areas of transplantation, how to use such set of genes to have a clear view of the graft status at a given time and what will be their contributions.