Chimerism post hematopoietic stem cells graft: Benefits of the quantitative PCR technique

The study of chimerism with the short tandem repeats (STRs) is an important tool in the follow-up of recipients after bone marrow transplantation (BMT). The STRs are reliable, reproducible and fast, and detect less than 5% of recipient's cells. However, according to the STR profiles of the donor and the recipient, one can be hampered to detect the apparition of the recipient's cells and thus make an early prediction of relapse. During the PCR-STR, the Taq polymerase can jump repeated sequences and thus generate "stutters" (ghost peaks) of low amplitude, located at the same level as the recipient's peak. Consequently, such a profile can be misinterpreted and generate a false positive or negative results. In such a case, another strategy can be useful: the real time quantitative PCR using Taqman technology with the specific nucleotide polymorphism (SNP). This technology without PCR competition shows better sensitivity (