Suitable Molecular Genetic Methods for the Monitoring of Cell Chimerism

Abstract

The molecular analysis of individual hematopoietic chimerism at a defined time after allogeneic hematopoietic stem cell transplantation represents an important non-specific marker of posttransplant course. The monitoring of its dynamic allows the identification of patients at a high risk of relapse. A variety of methods are used for the monitoring of cell chimerism. It is necessary to use sensitive molecular genetic methods for early detection of the autologous hematopoiesis. Quantitative multiplex real-time polymerase chain reaction (PCR) analysis can serve as a very sensitive (0.01 – 0.1%), relatively quick, and inexpensive method to detect < 1% of minor genotype. With an increasing ratio of minor genotype ( > 1%), it is more suitable to use short tandem repeats (STRs) for its analysis. Based on the differences in recipient/donor pair genotypes, at least two suitable informative polymorphisms located at different chromosomes can be selected. The combination of methods is appropriate, and the choice of the used method depends on the patient ’ s actual chimerism status. The cohort of 207 patients monitored at the Institute of Hematology and Blood Transfusion was divided into three subgroups according to their chimerism status (complete chimerism (CC), microchimerism, mixed chimerism (MC)) 3 years after allogeneic hematopoietic stem cell transplantation (allo-HSCT). A significant difference in the 3-year survival and 3-year relapse rates in all three subgroups was found.