Background: Recently molecular chimerism analysis after allogeneic hematopoietic stem cell transplantation (AHSCT) has become more important. The use of quantitative chimerism methods aims to assess the kinetics of engraftment to determine graft rejection and failure or relapse of the underlying disease after AHSCT. An accurate and sensitive determination of chimerism status is mandatory after AHSCT. This study aimed to compare two chimerism methods: Multiplex Short Tandem Repeat-Polymerase Chain Reaction (STR-PCR) and quantitative Real Time-PCR (qRT-PCR).
Methods: Thirty-nine blood samples at +28 day were used to extract DNA. Most patients had been diagnosed with acute leukemia (74.3 %) and other hematological diseases. For Multiplex STR-PCR method, PCR products were separated on an ABI 3130 Genetic Analyzer (Applied Biosystem, USA) and for qRT-PCR, an ABI 7500 (Applied Biosystem, USA) Plate System Real Time Analyzer was used to determine the quantification of chimerism per-centage.
Results: Of the 39 analyzed samples, 82% concordant chimerism results were detected for both STR-PCR and qRT-PCR methods. Ten mixed chimerisms (MC) were found by qRT-PCR whereas of only 3 MC cases were detected by STR-PCR. In the discordant group of 7 by qRT-PCR, we observed Acute Graft versus Host Disease (aGVHD). Three MC cases that were detected by both STR- and qRT-PCR methods died because of relapse.
Conclusions: The quantitative chimerism method along with multiplex STR-PCR method is important for early detection of MC. qRT-PCR methods can be valuable options in the prevention of graft failure and assisting with fast and early treatment strategies for patients undergoing AHSCT.