W K Jacky Lam1,2, Wanxia Gai1,2, Kun Sun1,2, Raymond S M Wong3, Rebecca W Y Chan1,2, Peiyong Jiang1,2, Natalie P H Chan4, Winnie W I Hui1,2, Anthony W H Chan4, Cheuk-Chun Szeto3, Siew C Ng3, Man-Fai Law3, K C Allen Chan1,2, Rossa W K Chiu1,2, Y M Dennis Lo5,2. 1. Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China. 2. Department of Chemical Pathology, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong SAR, China. 3. Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong SAR, China. 4. Department of Anatomical and Cellular Pathology, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong SAR, China. 5. Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China; loym@cuhk.edu.hk.
Abstract
BACKGROUND: There is much interest in the tissue of origin of circulating DNA in plasma. Data generated using DNA methylation markers have suggested that hematopoietic cells of white cell lineages are important contributors to the circulating DNA pool. However, it is not known whether cells of the erythroid lineage would also release DNA into the plasma. METHODS: Using high-resolution methylation profiles of erythroblasts and other tissue types, 3 genomic loci were found to be hypomethylated in erythroblasts but hypermethylated in other cell types. We developed digital PCR assays for measuring erythroid DNA using the differentially methylated region for each locus. RESULTS: Based on the methylation marker in the ferrochelatase gene, erythroid DNA represented a median of 30.1% of the plasma DNA of healthy subjects. In subjects with anemia of different etiologies, quantitative analysis of circulating erythroid DNA could reflect the erythropoietic activity in the bone marrow. For patients with reduced erythropoietic activity, as exemplified by aplastic anemia, the percentage of circulating erythroid DNA was decreased. For patients with increased but ineffective erythropoiesis, as exemplified by β-thalassemia major, the percentage was increased. In addition, the plasma concentration of erythroid DNA was found to correlate with treatment response in aplastic anemia and iron deficiency anemia. Plasma DNA analysis using digital PCR assays targeting the other 2 differentially methylated regions showed similar findings. CONCLUSIONS: Erythroid DNA is a hitherto unrecognized major component of the circulating DNA pool and is a noninvasive biomarker for differential diagnosis and monitoring of anemia.
BACKGROUND: There is much interest in the tissue of origin of circulating DNA in plasma. Data generated using DNA methylation markers have suggested that hematopoietic cells of white cell lineages are important contributors to the circulating DNA pool. However, it is not known whether cells of the erythroid lineage would also release DNA into the plasma. METHODS: Using high-resolution methylation profiles of erythroblasts and other tissue types, 3 genomic loci were found to be hypomethylated in erythroblasts but hypermethylated in other cell types. We developed digital PCR assays for measuring erythroid DNA using the differentially methylated region for each locus. RESULTS: Based on the methylation marker in the ferrochelatase gene, erythroid DNA represented a median of 30.1% of the plasma DNA of healthy subjects. In subjects with anemia of different etiologies, quantitative analysis of circulating erythroid DNA could reflect the erythropoietic activity in the bone marrow. For patients with reduced erythropoietic activity, as exemplified by aplastic anemia, the percentage of circulating erythroid DNA was decreased. For patients with increased but ineffective erythropoiesis, as exemplified by β-thalassemia major, the percentage was increased. In addition, the plasma concentration of erythroid DNA was found to correlate with treatment response in aplastic anemia and iron deficiency anemia. Plasma DNA analysis using digital PCR assays targeting the other 2 differentially methylated regions showed similar findings. CONCLUSIONS: Erythroid DNA is a hitherto unrecognized major component of the circulating DNA pool and is a noninvasive biomarker for differential diagnosis and monitoring of anemia.
Authors: Joshua Moss; Judith Magenheim; Daniel Neiman; Hai Zemmour; Netanel Loyfer; Amit Korach; Yaacov Samet; Myriam Maoz; Henrik Druid; Peter Arner; Keng-Yeh Fu; Endre Kiss; Kirsty L Spalding; Giora Landesberg; Aviad Zick; Albert Grinshpun; A M James Shapiro; Markus Grompe; Avigail Dreazan Wittenberg; Benjamin Glaser; Ruth Shemer; Tommy Kaplan; Yuval Dor Journal: Nat Commun Date: 2018-11-29 Impact factor: 14.919
Authors: Kun Sun; Peiyong Jiang; Ada I C Wong; Yvonne K Y Cheng; Suk Hang Cheng; Haiqiang Zhang; K C Allen Chan; Tak Y Leung; Rossa W K Chiu; Y M Dennis Lo Journal: Proc Natl Acad Sci U S A Date: 2018-05-14 Impact factor: 11.205