Intracellular IFN-γ and IL-2 expression monitoring as surrogate markers of the risk of acute rejection and personal drug response in de novo liver transplant recipients

► Intracellular cytokines as biomarkers predictive of the risk of AR pre- and post-transplantation. ► IFN-γ as a robust surrogate marker of AR for solid organ transplantation. ► %CD8+IFN-γ+, %CD8+IL-2+ and soluble IFN-γ as biomarkers of patients' susceptibility to treatment. ► Minimization of the technical variables associated with flow cytometry.