Analyses of Programmed Cell Death Protein 1 in High Immunologic-Risk Transplant Patients

Kidney transplant (KT) is the first therapeutic option for most patients with chronic renal failure that requires renal function replacement. The main complication associated with renal graft loss is immune rejection. The T regulatory pathways play a key role in this process, and abnormalities in some of these molecules could participate in the graft rejection. In this paper, our group performed an exploratory analysis of the behavior of the coinducible molecules (CD28, CTLA-4, ICOS, PD-1) in patients with KT rejection and control KT patients without rejection. The Mann-Whitney U test, used for 2 groups, showed significant differences (P = .0005), indicating that PD-1 is underexpressed in patients with allograft rejection. No differences were found in CD28+, regulatory T cells (T reg), CTLA-4, and ICOS, so we are proposing that PD-1 is a key player in the immunotolerance phenomenon and its underexpression participates in the rejection process. More research needs to be performed on this topic. •Kidney transplant has undoubtedly proven to be the best treatment for patients with advanced chronic kidney disease in terms of survival and quality of life.•Kidney transplant immunomodulation is performed by the regulatory T cells; T cell coregulation is one of the most important effects in renal transplant resulting in immunological tolerance.•New evidence in the literature pointed out that activation of T regulatory cells and T coinducible cells is an essential step for the induction of allograft tolerance.•The aim of this this article was to evaluate the T reg coinducible proteins CD28+, CTLA-4, ICOS, and PD-1 in the lymphocytes of patients with KT rejection and compare them with patients with no rejection.•Our first approach suggests that PD-1 underexpression could be a critical step in kidney rejection and leads to the opportunity to explore in detail this pathway in transplant patients.