[Application of short-tandem-repeat amplification and fluorescent-multiplex PCR for chimerism analysis]

The purpose of this study was to detect chimerism status of patients received allogeneic hematopoietic stem cell transplantation by using short tandem repeat (STR) amplification and fluorescence labeling multiplex polymerase chain reaction (PCR) combined with capillary electrophoresis, and to evaluate the prognostic value of monitoring chimerism status. DNA from peripheral blood or bone marrow of donors and recipients in different time were extracted, 10 different STR markers were co-amplified in a single reaction by using AmpFSTR Profiler Plus PCR amplification kits. Separation of the PCR products and fluorescence detection were performed by ABI PRISM 310 Genetic Analyzer with capillary electrophoresis. The Genescan and Genotype software were used for size calling and quantification of peak areas. The formula to calculate donor chimerism levels was based on the different allelic distribution types between donor and recipient. The results showed that 29 patients obtained complete donor chimerism and one patient obtained mixed chimerism in 28 days after transplantation. 22 patients continued complete donor chimerism and 8 patients showed mixed chimerism after long time follow up. 7 patients showed disease relapse after turning mixed chimerism from complete donor chimerism. The incidence of GVHD was higher in group of full donor chimerism. It is concluded that STR fluorescent-multiplex PCR is a rapid, automatic and sensitive method for chimerism tests after hematopoietic stem cell transplantation, which is a valuable tool as a dynamic monitoring for chimerism status to predict graft failure, disease relapse and occurrence of GVHD, and provides a basis for early clinical intervention in patients with allo-HSCT.