Follow up of patients after HSCT by chimerism detection can detect the outcome either engraftment, relapse or rejection. Many variables affect the result of chimerism either increasing or decreasing chimerism. Lineage specific chimerism is specific and sensitive than chimerism detection by whole blood. Here in this study the importance of these variables on the outcome of chimerism detection is studied.

Subject and method: This study was conducted at Ain Shams University Hospital during the period between January 2011and January 2015. 46 patients were included (16 child and 30 adult). They were transplanted for malignant and non malignant hematological diseases from totally matched siblings. The median duration of follow-up was one year.  Chimerism status was detected for all patients by polymerase chain reaction based on amplification of variable number tandem repeat (VNTR) markers. Six VNTR loci were detected in every subject pre-transplant in order to detect an informative locus to be used in follow up post-transplant. Also lineage specific chimerism and dilution experiment were conducted on some patients.

Results: One patient showed no informative locus pre-transplantation, 37 patients showed complete donor chimersm, two patients retained recipient pattern post-transplantation and six patients showed MC. Lineage cell specific chimerism and dilution experiment were conducted for patients who showed failure or mixed chimerism.

Conclusion: Chimerism detection by VNTR is dependable method to follow up patients after BMT however, some cases need some modifications as repeated analysis, short duration, lineage specific in comparison to whole blood analysis, dilution experiments in order to predict the outcome.

Keywords: Chimerism, Hematopoietic stem cells, Hematological diseases, Immunodeficiency.

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Dr Hala Talkhan

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