Mitochondrial DNA Minisatellites Showed Higher Informativeness and Sensitivity Than the Nuclear DNA Markers for the Quantitative Determination of Chimerism After Allogeneic Stem Cell Transplantation,

Abstract 4004 Background: Mitochondrial DNA (mtDNA) is widely used in forensic identification and anthropologic studies on account of its abundance resulting in preferential amplification, sequencing and inherent variability. We developed mtDNA markers to monitor donor cell engraftment after allogeneic stem cell transplantation(SCT), then compared with nuclear short tandem repeat (STR) markers. Patients and methods: The mtDNA control regions and six mtDNA minisatellites (mtMS) (303 poly C, 16184 poly C, 514 (CA) repeat, 3566 poly C, 12385 poly C and 12418 poly A) from the total DNA samples of 215 cases (donor, recipient and after allogeneic SCT) were amplified using the designated specific primers and PCR. The results were compared with those from the six short tandem repeat (STR) markers (D12S391, D18S51, F13A1, HUM RENA-4, HUM FABP2 and Amelogenin). Results: Polymorphisms in the mtDNA control region identify an informative marker in 88% (189 cases) of all cases. Among the six mtMS markers, the informativeness of 303 poly C and 16184 poly C mtMS was 63% and 67% respectively. A combination of direct sequencing through the mtDNA control region, 303poly C and 16184 poly C mtMS could completely distinguish the donor cells from the recipient cells. The results from a typical mixing experiment to determine the sensitivity revealed a detection limit (DL) of the gene scan analysis in a mtDNA mixture to be visible at 1% heteroplasmy in 303 poly C mtMS marker. However, the DL from D12S391 in the same mixing experiment was 5–10% heteroplasmy. Conclusions: mtMS markers, especially 303 poly C and 16184 poly C markers, can provide a sensitive, accurate and quantitative determination of mixed chimerism after a SCT. Disclosures: No relevant conflicts of interest to declare.