engleski

THE QUANTITATIVE PCR METHOD AS METHOD OF CHOICE IN CHIMERISM MONITORING AFTER HSCT

Chimerism analysis is a routine test performed in order to monitor engraftment or relapse after HSCT. A gold- standard method for this test was STR analysis. However, emergence of more sensitive qPCR-based methods has made them a more preferable method for chimerism analysis. The aim of the study was to evaluate applicability of a qPCR based chimerism monitoring method. For that purpose, 74 recipient/donor pairs have been tested using KMRtype Core kit (GenDx, Utrecht, the Netherlands). qPCR was carried out using Applied Biosystems 7500 Real-Time PCR System. Analysis was performed using KMRengine Chimerism Analysis Software. Among tested subjects, 36 patients were transplanted from a related donor, while 38 patients had an unrelated donor. Median number of informative markers (M) was calculated for patients and donors in both groups and was as follows: for patients with related donors M=4 (range 1-7) ; for related donors M=3 (range 0-7) ; for patients with unrelated donors M=6 (range 2-10) ; for unrelated donors M=6 (range 3-12). Analysis of informativeness for individual markers revealed that out of 30 tested markers, eight markers were informative in 15 or more cases for either patient or donor. However, only three markers (KMR013, KMR053, and KMR054) were placed among those eight for both patients and donors. Conversely, several markers showed a low level of informativeness as well as a high percentage (≈20%) of atypical results (KMR011, KMR035, KMR041, KMR057). In conclusion, the qPCR method has been shown to be adequate for majority of our patients. Additional testing was needed for only four patients with a related donor for whom a single informative marker was identified in the first analysis. Improvement of qPCR method applicability in comparison to the initial qPCR-based methods is encouraging and, although the level of PCR-STR method applicability has still not been reached, results of our study justifies implementation of qPCR in routine chimerism monitoring procedure.

qPCR, chimerism monitoring, HSCT

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