[What's new in immunological monitoring?]

By evaluating in vitro pro- and anti-inflammatory responses against the graft, the immunological monitoring predicts a presensitization to the transplanted tissue and assesses the risks of acute and chronic rejection without resorting to invasive tests. The monitoring of the T cell response before and after the graft, performed by recently developed immunological tests, has several advantages. In particular, it can predict the risk of acute cellular rejection induced by the direct pathway activation of anti-donor T-cells that can be evaluated by the Panel Reactive T cell test. It can also reveal a long term "under-immunosuppression" leading to chronic rejection, which involves indirect pathway activation of alloreactive cells of low frequency. Searching alloreactive CD4 and CD8 T cell precursors by Limiting Dilution Assay, anti-donor memory T response by ELIspot or urinary markers by proteomics and transcriptomics can enable the detection of this very faint response. Finally, the T cell response, evaluated by ELIspot or flow cytometric measurement of secreted intracytoplasmic cytokines (FACS), can detect a risk of infection. Though these methods are complex to use in clinical practice, the monitoring of T cell response should allow optimizing the choice of donors and immunosuppressive treatments and improving post-transplantation outcomes by reducing the risk of rejection and graft loss.