Allogeneic progenitor cell transplantation (AloPCT) is a procedure that has changed the prognosis of many malignant and non-
malignant hematologic diseases. For a period of time post-transplant, cellular subtypes from the donor and the host coexist,
giving the patient two hematopoietic systems. The term Chimera is used to indicate the dual origin of blood cells. This analysis
is important to determine whether engraftment or rejection has occurred. The determination of chimerism is based on PCR of
Short Tandem Repeat sequences (STRs). The PCR technique is easy to perform, reproducible, highly sensitive and specific.
Chimerism determination helps to improve the clinical approach to the patient, specifically when non-mieloablative conditioning,
lymphocyte donor infusion or modification of the immunosuppressive protocols have been employed. All of these manipulations
produce a high variability in engraftment, development of graft versus host disease (GVHD) and the likelihood to eliminate tumor
cells through graft versus tumor (GvT) effects.
