Predicting Cellular Rejection With a Cell-Based Assay

Abstract

Background Allospecific CD154+T-cytotoxic memory cells (CD154+TcM) predict acute cellular rejection (ACR) after liver or intestine transplantation (LTx, ITx) in small cohorts of children and can enhance immunosuppression management, but await validation and clinical implementation. Methods To establish safety and probable benefit, CD154+TcM were measured in cryopreserved samples from 214 children <21 years (NCT#1163578). Training set samples, n=158, were tested with research-grade reagents and 122 independent validation set samples were tested with cGMP-manufactured reagents after assay standardization and reproducibility testing. Recipient CD154+TcM induced by stimulation with donor cells were expressed as a fraction of those induced by HLA-non-identical cells in parallel cultures. The resulting immunoreactivity index (IR) if > 1 implies increased rejection-risk. Results Training and validation set subjects were demographically similar. Mean coefficient of test variation was <10% under several conditions. Logistic regression incorporating several confounding variables identified separate pre-transplant and post-transplant IR thresholds for prediction of rejection in respective training set samples. An IR ≥ 1.1 in post-transplant training samples, and IR ≥1.23 in pre-transplant training samples predicted LTx or ITx rejection in corresponding validation set samples in the 60-day post-sampling period with sensitivity, specificity, positive and negative predictive values of 84%, 80%, 64%, and 92%, respectively (AUC 0.792), and 57%, 89%, 78%, and 74%, respectively (AUC 0.848). No adverse events were encountered due to phlebotomy. Conclusions Allospecific CD154+T-cytotoxic memory cells predict acute cellular rejection after liver or intestine transplantation in children. Adjunctive use can enhance clinical outcomes.

Applicability, safety, and biological activity of regulatory T cell therapy in liver transplantation

“…Quantification of donor‐specific alloimmune responses : The proportion of alloreactive CD8 + memory T cells was assessed in cryopreserved PBMCs collected immediately before Treg infusion, and 7 days and 1 month afterward, employing the U.S. Food and Drug Administration (FDA)–approved Pleximmune test . This assay uses flow cytometry to quantify the number of recipient CD8 + CD45RO + memory T cells expressing CD154 following 16 hours of culture with surrogate donor PBMCs (matched to donor at a minimum of one antigen each at human leukocyte antigen [HLA]‐A, ‐B, and ‐DR loci or 6‐loci mismatched third‐party PBMCs).…”

“…PBMCs collected immediately before Treg infusion, and 7 days and 1 month afterward, employing the U.S. Food and Drug Administration (FDA)-approved Pleximmune test. 13,14 This assay uses flow cytometry to quantify the number of recipient CD8 + CD45RO + memory T cells expressing CD154 following 16 hours of culture with surrogate donor PBMCs (matched to donor at a minimum of one antigen each at human leukocyte antigen [HLA]-A, -B, and -DR loci or 6-loci mismatched thirdparty PBMCs). Similar experiments were conducted to quantify the frequency of CD154-positive memory CD8 + T cells following culture with an overlapping peptide mix of CMV pp65 antigen.…”

Renal allograft surveillance with allospecific T-cytotoxic memory cells

“…Determining the risk of renal transplant rejection can lead to early diagnosis and intervention and enhance graft survival. Previous studies have shown that enhanced donor-specific alloreactivity measured with allospecific CD154-expressing T-cytotoxic memory cells (CD154 þ TcM) predicts ACR after liver or intestine transplantation in children [1][2][3]. This FDA-approved test has a sensitivity and specificity approaching or exceeding 80% [3].…”

Predictive Value of Indocyanine Green Plasma Disappearance Rate on Liver Function and Complications After Liver Transplantation

“…However, almost all liver donors died from certain diseases, and some donors had critical diseases and deteriorating organ functions, including that of the liver. These factors significantly affect the post-transplant recovery of graft functions [ 2 ]. Clinically, it remains a main challenge to find a rapid and accurate approach to evaluate the function of transplanted livers and to predict the incidence of post-transplant complications [ 3 ].…”