**5. Conclusions**

A number of studies have shown that chimerism evaluation based on PCR amplification of polymorphic microsatellite STR markers is a readily applicable technique, informative almost for all patients, but less sensitive then real-time PCR of SNP and NPs DNA method. It is important to notice that complete, mixed chimerism, decreasing chimerism, and increasing chimerism are only the relative terms, because different laboratories have their own criteria to differentiate between complete donor chimerism and mixed decreasing chimerism, based on the method that is used, its sensitivity and local policies [43–45]. However, both provide a powerful tool in post-transplant decision making. They can document engraftment, predict graft failure or rejection, identify those patients who are at the highest risk to develop relapse and clarify the origin of the cells after relapse. According to the changes in chimerism status after transplantation, early implementation of immunotherapeutic measures such as rapid cessation of immunosuppression and donor lymphocyte infusion (DLI) with or without cytokine coadministration can be delivered as prophylaxis and seems to be highly efficacious in restoring CC and decreasing autologous cell contents.

We appreciate the huge Human Genomic Project, because we can use its results also in our small labs and participate on the patient quality of life improvement by chimerism monitoring after allogeneic haematopoietic stem cell transplantation.
