Proposed Topic (Most preferred): :
Research and Innovations (new projects / technology / innovations / service models)
Authors (including presenting author) :
Chan WYK (1), Cheuk DKL (1), Lee PPW (2), Leung WH (2)
Affiliation :
(1) Department of Paediatrics and Adolescent Medicine, Hong Kong Children’s Hospital
(2) Department of Paediatrics and Adolescent Medicine, The University of Hong Kong
Introduction :
Haploidentical haematopoietic stem cell transplantation (HSCT) had been increasingly employed as an alternative transplant strategy for patients who lack a suitable HLA-matched donor. Regular monitoring of engraftment and chimerism can be critical to establishing the success of transplant. Short tandem repeats-polymerase chain reaction (STR-PCR) based chimerism analysis is widely used and is our current standard clinical practice, but most has been performed by testing total leukocytes. Analysis of chimerism in selected lineage-specific populations could provide more important information to guide patient management. However, STR-PCR of isolated cells is labour intensive and time consuming. Alternatively, flow cytometry (FCM) can be used to evaluate chimeric status in haploidentical HSCT based on disparity of HLA antigens between donor and recipient, and lineage-specific chimerism analysis (LSCA) could also be performed simultaneously, quickly and easily with more precise results.
Objectives :
In this study, we aim to evaluate the correlation between FCM chimerism and STR-PCR chimerism, to explore the utility of FCM-LSCA results in clinical management, to describe the dynamics of lineage-specific chimerism in various T lymphocytes, B lymphocytes, natural killer cells and monocytes, to describe the clinical outcomes of mixed chimerism detected by FCM and to analyse factors associated with mixed chimerism.
Methodology :
Extra 3ml EDTA blood was collected at routine clinical time points (during donor and recipient workup, at post-HSCT day 7, 14, 21, 28; week 6, 8, 10, 12; 6 months and 1 year) for flow chimerism study to be performed in the research lab at Hong Kong Children’s Hospital. Correlation between FCM chimerism and the gold-standard STR chimerism was evaluated.
Result & Outcome :
Total 77 subjects (33 patients and 40 respective donors) had been recruited so far. Good correlation between FCM chimerism and STR chimerism had been demonstrated. The newly developed flow chimerism method is advantageous over existing gold standard as it is faster, less costly, less blood volume required, more sensitive and accurate, facilitates multi-parametric analyses and with extended utility. Apart from traditional haploidentical transplantation, the newly developed technique is also useful in chimerism monitoring for patients undergoing complementary (haplo-cord) transplant and haploidentical NK cell infusions.
