Lineage-specific chimerism analysis in nucleated cells, T cells and natural killer cells after myeloablative allogeneic hematopoietic stem cell transplantation

BACKGROUND Chimerism analysis is an important tool for assessing the origin of hematopoietic cells after allogeneic stem cell transplantation (allo-SCT) and can be used to detect impending graft rejection and the recurrence of underlying malignant or nonmalignant diseases. METHODS This study included 24 patients who underwent myeloablative allo-SCT. DNA was extracted from nucleated cells (NCs), T cells, and natural killer (NK) cells, and the chimerism status of these cell fractions was determined by STR-PCR performed using an automated fluorescent DNA analyzer. RESULTS Twenty-three out of the 24 patients achieved engraftment. Mixed chimerism (MC) in NCs, but not in T cells and NK cells, was significantly correlated with disease relapse. MC in all cell fractions was correlated with mortality. Ten patients (41.6%) developed extensive chronic GVHD. Six patients had MC in T cells, and 3 of them had chronic GVHD. Four patients with MC and relapse received donor lymphocyte infusion (DLI), and among them, 3 had secondary relapse. Further, the chimerism status differed among different cell lineages in 6 patients with myeloid malignancies. CONCLUSION The implications of MC in lymphocyte subsets are an important area for future research. Chimerism analysis in lineage-specific cells permits detection of relapse and facilitates the monitoring of therapeutic interventions. These results can provide the basic data for chimerism analysis after myeloablative SCT.