Development of an algorithm of satellite markers for monitoring chimerism status in post-allogeneic haematopoietic stem cell transplantation patients.

Summary Introduction:  Analysis of variable number tandem repeats (VNTRs) by polymerase chain reaction (PCR) is a common method used to predict engraftment status in post-allogeneic haematopoeitic stem cell transplantation (HSCT) patients. Different populations have different copies of repeated DNA sequence and hence, different percentage of informativeness between patient and donor. Methods:  PCR amplification of four highly polymorphic VNTR markers (YNZ-22, D1S80, D1S111 and ApoB) was conducted on 60 patient-donor pairs. The informativeness of the markers was analysed using 3% agarose gel electrophoresis. Results:  We developed an algorithm for identification of informative VNTR markers in 60 post-allogeneic HSCT patients. YNZ-22 was the most informative (72%), followed by D1S80 (63%) and D1S111 (60%), while the least informative was ApoB (47%). The degree of informativeness achieved was 95%, which could discriminate 57 patient-donor pairs, when all four markers were combined. Conclusion:  Since population genetic studies on VNTR loci are not well established in Southeast Asia, the present study is useful to determine reliable markers during the initial screening step of chimerism analysis. By following this algorithm, we are able to reduce time and cost of finding a suitable VNTR marker in our cohort.