Comparison of Total Leukocyte Chimerism and Lymphocyte Subset Chimerism for Early Detection of Post-Transplant...

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is associated with risks of GVHD, graft rejection, and relapse. Chimerism monitoring supports early detection, though the prognostic value of B- and T-cell chimerism remains unclear. We aimed to compare total leukocyte chimerism with lymphocyte subset chimerism to determine their clinical utility in predicting relapse, GVHD, and overall survival (OS) in allo-HSCT recipients.

Patients with hematologic malignancies who underwent allo-HSCT from an HLA-matched sibling or unrelated donor were included. Total leukocyte, B-cell, and T-cell chimerism were analyzed on days 28 and 90 post-transplant. DNA was isolated using a DTAB/CTAB-based method, and chimerism was determined via STR-PCR and capillary electrophoresis. Associations with relapse, GVHD, and event-free survival (EFS) were evaluated. Statistical analysis was performed using SPSS v21.0, including Fisher's exact test, Mann-Whitney U test, and Kaplan-Meier survival analysis.

Among 21 allo-HSCT recipients, full donor chimerism (FDC) was observed in 95.2% and mixed chimerism (MC) in 4.8%. Most patients with acute (52.4%) and chronic GVHD (47.6%), relapse (4.8%), or death (19.0%) had FDC. These patterns were consistent across B, T, and total leukocyte subsets on days 28 and 90. Mean disease-free survival was 8.7 months; OS was 11.3 months. No statistically significant association was found between chimerism type and relapse, GVHD, or survival. EFS also did not differ between FDC and MC.

Lineage-specific chimerism analysis may enhance early detection of post-transplant complications and improve monitoring precision. However, its clinical utility requires validation in larger cohorts.