Recent Thymic Emigrants and Tregs Expressing CD31 and CD45RA Are Decreased at Day 100 and Prognostic for Chronic GvHD in Children: Results From the Applied Biomarkers of Late Effects (ABLE)/Pediatric Blood and Marrow Transplant Consortium 1202 Study

Abstract

Background: Our group and others (Greinix BBMT 2015) have shown that higher proportions of recent thymic emigrants (RTEs: CD4+CD45RA+CD31+) at d100 are a prognostic biomarker for chronic GvHD in adults. We sought to understand whether RTEs, as well as regulatory T cells (CD4+CD25+CD127Lo) that co-express naive and recently emigrated markers (CD45RA+CD31+; Treg RTEs) were prognostic at d100 for pediatric cGvHD. Methods: Allo-HCT patients (<18yrs) with malignant and non-malignant diagnoses were enrolled before HCT and prospectively followed for cGvHD until 1-year post-HCT. Blood was analyzed by 8-color flow cytometry at d100 (+/-14d) for prognostic cellular cGvHD biomarkers. Mean values are reported. Biomarkers were considered clinically significant if means were >1.5x or <0.7x the control and P