Evaluation of two short tandem repeat multiplex systems for post-haematopoietic stem cell transplantation chimerism analysis.

INTRODUCTION The follow-up of chimerism status after allogeneic haematopoietic stem cell transplantation (HSCT) is essential to predict successful engraftment to assess the development of graft-versus-host disease, graft rejection and disease relapse. Analysis of short tandem repeats (STR) via polymerase chain reaction is frequently used for chimerism determination. However, most commercially-available kits have been designed for forensic purposes and may not be optimal for chimerism analysis. The present study aims to identify suitable STR markers for patient-donor pairs of predominantly Malay and Chinese ethnicity using two commercially-available forensic kits. METHODS We analysed six STR loci, namely, CSF1PO, TPOX, TH01 (using the CTT multiplex system) and F13A01, FESFPS and vWA (using the FFv multiplex system) in 33 human leukocyte antigen-matched Malaysian patient-donor pairs to determine the suitability of these two multiplex systems for chimerism analysis in our local population. RESULTS Informativity (different alleles in donor and recipient) of each individual locus was TH01 73 percent, vWA 73 percent, F13A01 52 percent, CSF1PO 61 percent, FESFPS 39 percent and TPOX 45 percent. When combined, the six STR loci were able to give chimerism results in 31 out of 33 (94 percent) cases. CONCLUSION We found that TH01 and vWA are informative STR targets for post-HSCT chimerism analysis in predominantly Malay and Chinese patient-donor pairs. The commercially-available kits will also permit laboratories without extensive molecular biology capabilities to perform DNA typing in HSCT recipients.