A rapid test of alloreactivity based on interleukin-2 mRNA expression might identify liver transplant recipients with donor-specific hyporesponsiveness

Background. Immunosuppression withdrawal is feasible in some liver transplant (OLT) recipients but may lead to severe rejection in others, underlying the need for reliable biomarkers to identify patients with tolerant profile in whose weaning/withdrawal could be safely proposed. We evaluated the value of real-time polymerase chain reaction (PCR)based measurement of interleukin (IL)-2 mRNA in mixed lymphocyte reaction (MLR) to monitor in vitro anti-donor reactivity in OLT patients. Methods. MLR were performed in three patients undergoing living donor OLT using a tolerogenic protocol including donor stem cells. IL-2 mRNA production in MLR was measured by PCR at several intervals after OLT. Results. In the early posttransplant period, three patients presented with global immunodeficiency, as indicated by low IL-2 mRNA production against both donor. and third-party antigens. In the two patients who has immunosuppression successfully withdrawn, donor-specific hyporesponsiveness was observed thereafter: IL-2 mRNA production against donor cells remained low, while IL-2 mRNA production against a third-party antigen-presenting cells progressively recovered. No such modulation of the anti-donor response was observed in the patient in whom withdrawal led to rapid rejection. Conclusion. Measurement of IL-2 mRNA production in MLR might preffer a tool to monitor anti-donor reactivity after OLT for decisions to minimize or withdraw immunosuppression in patients displaying donor-specific hyporesponsiveness