Early hematopoietic chimerism monitoring and molecular engraftment characteristic by STR-PCR method in patients after alloHSCT

Abstract

Allogeneic hematopoietic stem cell transplantation (alloHSCT) is a curative treatment for proportion of patients suffering from malignant and non-malignant hematological disorders. Successful transplantation is a process that requires the engraftment of pluripotent hematopoietic stem cells which can re-establish normal hemopoesis and immune system. Distinguishing between donor and host origin of bone marrow and blood cells is crucial for monitoring of engraftment process. One of the most useful tools for engraftment monitoring is the assessment of hematopoietic chimerism after alloSCT that describes the percentage of donor hematopoietic in a transplant recipient.

Thirty eight adult patients after alloHSCT were included into the study. In total 43 allogeneic stem cell transplantations were performed. Hematopoietic chimerism was assessed by STR-PCR technique. The analysis of early chimerism were performed starting from 2^nd to 14th day on every 2 days than to 28 days weekly and on day +30 after alloHSCT.

Early hematopoietic chimerism assessment demonstrated that the kinetics of chimerism in patients after alloSCT was compatible with linear trend (R²=0.996) and in patients after alloNMSCT was compatible with logarithmic trend (R²=0.959). The hematopoietic chimerism level was higher in alloSCT on day 2 the difference was statistically significant (p=0.0048).

Molecular engraftment preceded hematological engraftment in patients after either myeloablative or non-myeloablative conditioning regiments (alloSCT patients p=1.44×10⁻¹², alloNMSCT p=2.12×10⁻⁶).

Earlier ME was observed in patients after alloHSCT and alloSCT who received more than 3×10⁶ CD34+ cells/kg (alloSCT p=0.0013, alloHSCT p=0.021). The difference was statistically significant.