Evaluation of a rapid flow cytometry assay to assess functional engraftment in CGD patients post-transplant and comparison with molecular chimerism.

This study explores the value of the Dihydrorhodamine-123 (DHR-123) flow cytometry assay to rapidly measure donor neutrophil engraftment (chimerism) in patients with Chronic Granulomatous Disease (CGD) following hematopoietic stem cell transplant (HSCT). Flow cytometry-based chimerism testing was compared with traditional molecular methods including sequence tandem repeats (STR), Quantitative-PCR DNA fingerprinting, and next-generation sequencing (NGS). Results comparing the two technologies in a cohort of CGD patients and healthy control subjects demonstrated that the DHR-123 based flow cytometry chimerism assay is an accurate, inexpensive, and rapid method for assessing functional donor neutrophil engraftment post-transplant, and which demonstrated significant correlation with the results of the molecular chimerism assays (R2 = 0.9965), making it a valuable tool for ongoing chimerism monitoring post-transplant. The flow cytometry-based assay offers a more rapid and inexpensive alternative to traditional molecular chimerism techniques.