The significance of mixed chimaerism and cell lineage chimaerism monitoring in paediatric patients post haematopoietic stem cell transplant

Abstract

Haematopoietic stem cell transplants (HSCTs) are carried out across the world to treat haematological and immunological diseases which would otherwise prove fatal. Certain diseases are predominantly encountered in paediatric patients, such severe primary immunodeficiencies (PID) and diseases of inborn errors of metabolism (IEM). Chimaerism testing for these disorders has different considerations compared to adult diseases. This review focuses on the importance of cell-lineagespecific chimaerism testing and examines the appropriate cell populations to be assessed in individual paediatric patient groups. By analysing disease-associated subpopulations, abnormalities are identified significantly earlier than in whole samples and targeted clinical decisions can be made. Chimaerism methods have evolved over time and lead to an ever-increasing level of sensitivity and biomarker arrays to distinguish between recipient and donor cells. Short tandem repeat (STR) is still the gold standard for routine chimaerism assessment, and hypersensitive methods such as quantitative and digital polymerase chain reaction (PCR) are leading the forefront of microchimaerism testing. The rise of molecular methods operating with minute DNA amounts has been hugely beneficial to chimaerism testing of paediatric samples. As HSCTs are becoming increasingly personalised and risk-adjusted towards a child's individual needs, chimaerism testing needs to adapt alongside these medical advances ensuring the best possible care.How to cite this article: Kricke S, Rao K, Adams S. The significance of mixed chimaerism and cell lineage chimaerism monitoring in paediatric patients post haematopoietic stem cell transplant.

The predictive value of T-cell chimerism for disease relapse after allogeneic hematopoietic stem cell transplantation

“…Chimerism is a dynamic process and ever-changing, and MC is responsible for allo-HSCT failure ( 21 ). The most appropriate chimerism analysis is based on disease and allo-HSCT type ( 22 ). However, there is a lack of comparative analysis of different chimerism of dynamic changes.…”

“…Through successive tests can be able to effectively identify high-risk relapse patients, which indicates close monitoring is extremely important ( 26 , 27 ). Donor cells need time to rebuild the hematopoietic system after allo-HSCT, so it is not advisable to assess the chimerism status after transplantation too early ( 22 ). In this study, the study was examined from 15 days after allo-HSCT, and the study’s duration was restricted to a 30-month follow-up period.…”

“…The change trend of the chimerism rate is opposite to the number of relapse and death patients. The relapse of leukemia/MDS is accompanied by a drop in donor chimerism ( 22 ). Hence, these findings further support that chimerism can predict clinical relapse.…”

Prevalence of adsorbed A antigen onto donor‐derived group O red cells in children following stem cell transplantation: A single‐centre evaluation

“…Engraftment studies showed that the patient had 100% myeloid and whole blood engraftment confirming that the transplanted cells were what was detected in the patient. Erythroid engraftment can only be directly assessed by separating erythroid precursors from bone marrow samples (such as CD235a‐positive selection) [5]; however, bone marrow samples were not available for this patient. Myeloid engraftment has been described as a surrogate marker for erythroid engraftment [5], and given that the patient is fully engrafted in whole blood and myeloid without evidence of any low‐level mixed chimerism, it can be concluded that the patient's erythroid cell lineage is also fully engrafted.…”