P021 Development of laboratory-developed chimerism analysis assay targeting t lymphocytes in hematopoietic stem cell transplantation

Abstract

Aim Hematopoietic stem cells transplantation (HSCT) is one of the gold standard treatment for the patients with hematologic malignancies. After the transplantations, the engraftment of the stem cells is monitored using various methods. Short tandem repeats (STR) are one of the sensitive markers for chimerism. We designed laboratory-developed chimerism analysis assay using 8 short tandem repeat regions. Methods Total 38 patients who received allogeneic HSCT were involved in this study. The diagnosis of the patients included acute myeloid leukemia, precursor lymphoblastic leukemia, myelodysplastic syndrome, hemophagocytic lymphohistiocytosis, chronic eosinophilic leukemia, paroxysmal nocturnal hemoglobinuria, juvenile myelomonocytic leukemia, plasma cell myeloma, and congenital neutropenia. DNA was extracted from both ACD anticoagulated blood and T lymphocytes isolated by EasySep (STEMCELL Technologies, Vancouver, Canada). We designed the assays, named LDT 8, targeting D3S1358, D5S818, TH01, D7S820, D12S391, FGA, D18S51, and Penta E. The amplicons were analyzed using Performance Optimized Polymer 7 (Applied Biosystems Norwalk, USA) by 3130 xl genetic analyzer (Applied Biosystems). The results LDT8 were compared with commercially available PowerPlex 21 (Promega, Madison, USA) and Mentype 13 (Biotype, Dresden, Germany). In addition, we also compared the chimerism status of whole blood to that of T lymphocyte. Results Compared with PowerPlex 21 and Mentype 13 respectively, 90.1% and 84.9% of specimens showed less than 5%p in overall discrepancies. In the comparison between whole blood and T lymphocytes, most of specimens showed the higher recipient proportion of DNA in T lymphocytes. Conclusions We developed the economical and effective chimerism analysis assay using 8 short tandem repeat regions. Also, we identified discrepancies among two different cell sources. Further study for long-term monitoring of chimerism status in different cell subsets would be helpful in patients who received hematopoietic stem cell transplantation.