Characteristics of alloreactive T cells measured before renal transplantation

Summary Several assays to measure pre‐existing allospecific T cell immunity in renal transplant candidates have been developed in the past years. In 46 patients, we used flow cytometry‐based mixed lymphocyte culture to measure the precursor frequency and phenotype of alloreactive T cells before renal transplantation, using donor‐specific or third‐party cells for allostimulation. Allostimulation induced up‐regulation of co‐stimulatory molecules, chemokine receptors relevant for migration of T cells into the graft and effector proteins. Recipients prone for acute rejection had a higher precursor frequency of alloreactive CD8 + T cells and a lower percentage of interleukin (IL)‐7Rα expressing alloreactive CD8 + T cells than non‐rejectors. These data point to quantitative and qualitative differences between T cells of patients who will experience acute cellular rejection episodes from those who will not.