Predicting Cellular Rejection With a Cell-Based Assay: Preclinical Evaluation in Children

Area of Science:

• Immunology
• Transplantation Science
• Clinical Diagnostics

Background:

• Allospecific CD154+T-cytotoxic memory cells (CD154+TcM) are potential biomarkers for predicting acute cellular rejection.
• Previous studies in small cohorts of children showed promise for CD154+TcM in liver and intestine transplantation (LTx/ITx).
• Clinical implementation and validation were pending for broader application in immunosuppression management.

Purpose of the Study:

• To establish the safety and probable benefit of using CD154+TcM as a predictive marker for acute cellular rejection.
• To validate the diagnostic accuracy of CD154+TcM in a larger cohort of pediatric transplant recipients.
• To standardize the assay for clinical use and assess its reproducibility.

Main Methods:

• Cryopreserved samples from 214 children (<21 years) were analyzed.
• A training set (n=158) and an independent validation set (n=122) were used.
• The immunoreactivity index (IR) was calculated based on recipient CD154+TcM stimulated with donor cells versus HLA non-identical cells.

Main Results:

• Assay standardization and reproducibility testing showed a mean coefficient of variation <10%.
• Logistic regression identified distinct pretransplant and posttransplant IR thresholds for rejection prediction.
• The CD154+TcM assay demonstrated significant sensitivity and specificity in predicting LTx/ITx rejection within 60 days post-sampling.

Conclusions:

• Allospecific CD154+T-cytotoxic memory cells are validated predictors of acute cellular rejection in pediatric LTx and ITx.
• The adjunctive use of CD154+TcM testing can enhance clinical outcomes in pediatric transplant recipients.
• The study establishes safety, with no adverse events reported due to phlebotomy.