Kanaan SB, Urselli F, Radich JP, et al. Ultrasensitive Chimerism Enhances Measurable Residual Disease Testing Post-Allogeneic Hematopoietic Cell Transplantation. Blood Advances. 2023; (doi: 10.1182/bloodadvances.2023010332).
A proof-of-concept test of an ultrasensitive assay validated the post-allogeneic hematopoietic cell transplantation (allo-HCT) measurement of chimerism to increase measurable residual disease (MRD) data. The panel of qPCR assays developed incorporated TaqMan chemistry that could assess chimerism to a degree of 1 in a million — sensitive enough to identify risk of relapse, the researcher hypothesized. The panel was tested on a retrospective cohort of patients with acute leukemia with known outcomes after allo-HCT. The data showed that relapse correlated with absolute recipient chimerism proportions and rates at which these quantities grew in bone marrow aspirate (BMA) in the first 540 days after transplantation. The limited correlation between relapse and detectable MRD by flow cytometry in BMA was enhanced when paired with increased recipient chimerism in BMA. These findings show chimerism used along with MRD assays could better identify patients at highest relapse risk as early intervention candidates.