In Situ Immune Profiling of Heart Transplant Biopsies Improves Diagnostic Accuracy and Rejection Risk Stratification

Highlights •Quantitative multiplexed immune-phenotyping of cardiac allograft biopsies provides novel diagnostic and prognostic information about allograft health. •Reduced proportions of cells expressing PD-L1 and FoxP3 are associated with clinical evidence of serious allograft injury, even when conventional histologic analysis provides falsely reassuring histologic rejection grades. •The proportions of PD-L1- and FoxP3-expressing cells are dynamic within cardiac allografts, and reduced levels can precede future rejection.