title: Underestimation of recipient DNA in bone marrow by post-transplant chimerism analyses using DNA extracted from EDTA-collected aspirate samples in pediatric acute myeloid leukemia.
abstract: OBJECTIVE
  Chimerism analysis (CA) is essential for post-transplant surveillance. DNA from bone marrow (BM) aspirates drawn into EDTA specimen tubes (EDTA-BM) is widely used for CA. Since EDTA-BM is subject to peripheral dilution, however, DNA from aspirate particle smears (PS-BM) might better represent BM chimerism status. In this regard, we evaluated the influence of BM sources on CA.
  
  
  METHODS
  Study subjects were consecutive pediatric AML patients who had experienced relapse after allogeneic stem cell transplantation with the interval between CA before relapse (pre-relapse) and at relapse <6 months. We compared chimerism status at the 2 time-points by fluorescence PCR on STR markers using EDTA-BM vs PS-BM.
  
  
  RESULTS
  Eight patients were eligible for this study. The recipient DNA (%R) from EDTA-BM was 0% at pre-relapse in all except 2 with 1.6% and 1.3%, while %R using PS-BM revealed mixed chimerism in all 8, %R ranging 1.6-13.2% (median 3.75%). The %R from EDTA-BM was 0.9-79.3% at relapse (29.15%), while %R from PS-BM was 3.8-86.6% (60.15%). The difference of %R (Δ%R), %R[PS-BM]-% R[EDTA-BM], was median 3.15% (1.6-13.2%) at pre-relapse and median 12.1% (2.1-60.7%) at relapse.
  
  
  CONCLUSIONS
  Our study showed CA using EDTA-BM significantly underestimated %R. Our observation might have a ramification to other quantitative workup in hematologic malignancy.
authors.affiliation: Department of Laboratory Medicine & Genetics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Chang-Hun
authors.initials: CH
authors.lastname: Park
authors.forename: Min-Jung
authors.initials: MJ
authors.lastname: Song
authors.forename: Hee-Jin
authors.initials: HJ
authors.lastname: Kim
authors.forename: Chang-Seok
authors.initials: CS
authors.lastname: Ki
authors.forename: Soo Hyun
authors.initials: SH
authors.lastname: Lee
authors.forename: Keon Hee
authors.initials: KH
authors.lastname: Yoo
authors.forename: Ki Woong
authors.initials: KW
authors.lastname: Sung
authors.forename: Hong Hoe
authors.initials: HH
authors.lastname: Koo
authors.forename: Sun-Hee
authors.initials: SH
authors.lastname: Kim
mesh_terms: D000293:Adolescent; D001853:Bone Marrow / Q000502:physiology*; D002648:Child; D002675:Child, Preschool; D046528:Chimerism; D004247:DNA / Q000032:analysis*; D004492:Edetic Acid; D005260:Female; D018380:Hematopoietic Stem Cell Transplantation; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007223:Infant; D015470:Leukemia, Myeloid, Acute / Q000235:genetics* / Q000517:prevention & control / Q000601:surgery; D008297:Male; D012008:Recurrence; D018183:Transplantation Chimera / Q000235:genetics
chemical_list: D004247:DNA; D004492:Edetic Acid