Willy A. Flegel, MD

MD, University of Frankfurt, Germany
Privatdozent, University of Ulm, Germany

Dr. Flegel earned his medical degree and received a Doctor of Medicine by research (Dr. med., magna cum laude) at the University of Frankfurt, trained in transfusion medicine at the University of Ulm and performed post-doctoral research at the University of California at San Diego. He completed his habilitation (Privatdozent) at the University of Ulm.

He was appointed head of the Immunohematology Department at the German Red Cross Blood Center in Ulm and member of the Medical Faculty, University of Ulm, as Professor (apl. Prof.). He is Professor (adjunct), Georgetown University Medical Center, Washington DC since 2015 and Guest Professor, Huazhong University of Science and Technology, Wuhan, China since 2018.

Dr. Flegel has been involved as physician in blood transfusion medicine since 1985 and at the forefront of research on blood cell antigens since 1994. His professional activities include founding and coordinating the German Rare Donor Program 1999 – 2009; serving as a member of the International Society of Blood Transfusion (ISBT) Working Parties for Rare Donors 2000 – 2010, on Red Cell Immunogenetics and Blood Group Terminology since 2004 and on Immunohematology since 2014; member of the Molecular Testing Standards Committee of the Association for the Advancement of Blood & Biotherapies (AABB) since 2019, as its chairperson since 2023; inventing for patents in the field of molecular immunohematology; and organizing the oldest and largest external quality assessment (EQA) scheme for molecular immunohematology proficiency since 2006 in an effort to enhance patient safety internationally.

He serves as Associate Editor of Blood Transfusion, Senior Editor of Journal of Translational Medicine, International Editorial Board Member of Chinese Medical Journal, and previously as Associate Editor of Transfusion (2012 – 2024). He has published more than 250 articles in scientific journals, authored a medical-legal textbook on transfusion medicine and has written book chapters.

Dr. Flegel came to the Department of Transfusion Medicine (DTM) at the NIH Clinical Center in 2009 as Chief, Laboratory Services Section. In this role, he directs the Transfusion Services (TSL) and HLA Laboratories. During his tenure, the TSL expanded genotyping for blood cell antigens and the HLA laboratory implemented next generation sequencing.

Dr. Flegel is an appointed Senior Research Physician. His research interests include red cell genotyping; relationship of genotype, phenotype, and function of blood group proteins; stem cell surface antigens in vivo and during ex vivo expansion; and immunogenetics in hematopoietic progenitor cell transplantation.

• NIH Clinical Center CEO Award, 2022 (Innovation)
• NIH Clinical Center CEO Award, 2021 (Innovation)
• NIH Clinical Center CEO Award, 2017 (Strategic Initiative) NIH Clinical Center Director's Award, 2015 (Patient Care)
• NIH Clinical Center Director's Award, 2012 (Patient Care)
• NIH Clinical Center Director's Award, 2010 (Strategic Initiative)
• Honorary Member of the Swiss Association for Transfusion Medicine, 2005
• Philip Levine Award of the German Society for Transfusion Medicine and Immunohematology, 2004

Books

Flegel WA (Chair) and Molecular Testing Standards Committee. Molecular Testing for Red Cell, Platelet, and Neutrophil Antigens. AABB, Bethesda MD 2024, 7th Edition

Lippert H-D, Flegel WA. Kommentar zum Transfusionsgesetz (TFG) und den Hämotherapie-Richtlinien. XXXIX, 521 pages. Springer, Berlin 2002

Book Chapters

Flegel WA, Wagner FF. Blutgruppen: Alloantigene auf Erythrozyten. In: Kiefel V (Ed.) Transfusionsmedizin und Immunhamatologie. Springer, Berlin 2010, 4th Edition

Flegel WA. Transfusion. In: Delves PJ, Roitt IM (Eds.) Encyclopedia of Immunology. Academic Press, London 1999, 2nd Edition

Journal Reviews, Editorials and Commentaries

Flegel WA. Chimerism and mosaicism shape our physical constitution and impact medical conditions. Br J Haematol 205: in press, 2024

Flegel WA, Srivastava K. 40 years of researching the Del phenotype results in a change of transfusion practice. Transfusion 64: 1187 – 1190, 2024

Flegel WA. Patients with red cell antibodies: registries improve patient care by increasing patient safety, reducing costs, and enabling health information exchange Blood Transfus 22: 279 - 282, 2024

Flegel WA. Modern Rhesus (Rh) typing in transfusion and pregnancy. Canadian Med Assoc J 193: E124, 2021

Flegel WA. COVID-19: risk of infection is high, independently of ABO blood group. Haematologica 105: 2706 – 2708, 2020

Flegel WA. COVID-19 insights from transfusion medicine. Br J Haematol 190: 715 – 717, 2020

Flegel WA. Mosaicism by somatic non-functional mutations: one cell lineage at a time. Haematologica. 104: 425 – 427, 2019

Flegel WA, Chen Q, Castilho L, Keller MA, Klapper EB, Lane WJ, Pirenne F, Stack G, St-Louis M, Tormey CA, Waxman DA, Weinstock C, Wendel S, Denomme GA. Molecular immunohaematology round table discussions at the AABB Annual Meeting, Orlando 2016. Blood Transfus 16: 447 – 456, 2018

Flegel WA. Red cell alloimmunisation: incidence and prevention. Lancet Haematol 3: e260 – e261, 2016

Flegel WA. Pathogenesis and mechanisms of antibody-mediated hemolysis. Transfusion 55: S47 – S58, 2015

Flegel WA, Natanson C, Klein HG. Does prolonged storage of red blood cells cause harm? Br J Haematol 165: 3 – 16, 2014

Flegel WA. Molecular genetics and clinical applications for RH. Transf Apher Sci 44, 81 – 91, 2011

Flegel WA. Immunogenicity reloaded. Blood 114, 3979 – 3980, 2009

Flegel WA. Will MICA glitter for recipients of kidney transplants? N Engl J Med 357, 1337 - 1339, 2007

Flegel WA. Homing in on D antigen immunogenicity. Transfusion 45, 466 – 468, 2005

Journal Articles

Updated list of 250+ publications in PubMed and at Scopus with an h-index of 51 in 2024

Ohto H, Ito S, Srivastava K, Ogiyama Y, Uchikawa M, Nollet KE, Flegel WA. Asian-type DEL (RHD*DEL1) with an allo-anti-D: a paradoxical observation in a healthy multiparous woman. Transfusion 63: 1601 -1611, 2023

Srivastava K, Fratzscher AS, Lan B, Flegel WA. Cataloguing experimentally confirmed 80.7 kb-long ACKR1 haplotypes form the 1000 Genomes Project database. BMC Bioinformatics 22; 273, 2021

Zaimoku Y, Patel BA, Adams SD, Shalhoub R, Groarke EM, Lee AAC, Kajigaya S, Feng X, Rios OJ, Eager H, Alemu L, Raffo DQ, Wu CO, Flegel WA, Young NS. HLA associations, somatic loss of HLA expression, and clinical outcomes in immune aplastic anemia. Blood 138: 2799 – 2809, 2021

Srivastava K, Khil PP, Sippert E, Volkova E, Dekker JP, Rios M, Flegel WA. ACKR1 alleles at 5.6 kb in a well-characterized renewable US Food and Drug Administration (FDA) reference panel for standardization of blood group genotyping. J Mol Diagn 22: 1272 – 1279, 2020

Ombrello AK, Qin J, Hoffmann PM, Kumar P, Stone D, Jones A, Romeo T, Barham B, Pinto-Patarroyo G, Toro C, Soldatos A, Zhou Q, Deuitch N, Aksentijevich I, Sheldon SL, Kelly S, Man A, Barron K, Hershfield M, Flegel WA, Kastner DL. Treatment strategies for deficiency of adenosine deaminase 2. N Engl J Med 380: 1582 – 1584, 2019

Yin Q, Srivastava K, Gebremedhin A, Makuria AT, Flegel WA. Long-range haplotype analysis of the malaria parasite receptor gene ACKR1 in an East-African population. Human Genome Variation 5: 26, 2018

Charles BA, Hsieh MM, Adeyemo AA, Shriner D, Ramos E, Chin K, Srivastava K, Zakai NA, Cushman M, McClure LA, Howard V, Flegel WA, Rotimi CN, Rodgers GP. Analyses of genome wide association data, cytokines, and gene expression in African-Americans with benign ethnic neutropenia. PLoS One 13: e0194400, 2018

Ouchari M, Srivastava K, Romdhane H, Jemni Yacoub S, Flegel WA. Transfusion strategy for weak D Type 4.0 based on RHD alleles and RH haplotypes in Tunisia. Transfusion 58: 306 – 312, 2018

Srivastava K, Stiles DA, Wagner FF, Flegel WA. Two large deletions extending beyond either end of the RHD gene and their red cell phenotypes. J Hum Genet 63: 27 – 35, 2018

Allen ES, Srivastava K, Hsieh MM, Fitzhugh CD, Klein HG, Tisdale JF, Flegel WA. Immunohematologic complications in patients with sickle cell disease undergoing hematopoietic progenitor cell transplantation. Lancet Haematol 4: e553- e561, 2017

Flegel WA, Gottschall JL, Denomme GA. Integrating red cell genotyping into the blood supply chain: a population-based study. Lancet Haematol 2: e282 – e288, 2015

Rujirojindakul P, Flegel WA. Applying molecular immunohematology to regularly transfused thalassemic patients in Thailand. Blood Transfus 12: 28 – 35, 2014

Flegel WA, Chiosea I, Sachs UJ, Bein G. External quality assessment in molecular immunohematology: the INSTAND proficiency test program. Transfusion 53: 2850 – 2858, 2013

Schmid P, Flegel WA. Codon usage in vertebrates is optimized for a low risk of acquiring nonsense mutations. J Transl Med 9: 87, 2011

Schäfer R, Schnaidt M, Klaffschenkel RA, Siegel G, Schüle M, Rädlein MA, Hermanutz-Klein U, Ayturan M, Buadze M, Gassner C, Danielyan L, Kluba T, Northoff H, Flegel WA. Expression of blood group genes by mesenchymal stem cells. Br J Haematol 153: 520 – 528, 2011

Schwartz, S, Vergoulidou, M, Schreier, E, Loddenkemper, C, Reinwald, M, Schmidt-Hieber M, Flegel WA, Thiel E, Schneider T. Norovirus gastroenteritis causes severe and lethal complications after chemotherapy and hematopoietic stem cell transplantation. Blood 117, 5850 – 5856, 2011

Fasano RM, Monaco A, Riehm Meier E, Pary P, Lee-Stroka AH, Otridge J, Klein HG, Marincola FM, Kamani NR, Luban NLC, Stroncek D, Flegel WA. RH genotyping in a sickle cell disease patient contributing to hematopoietic stem cell transplantation donor selection and management. Blood 116, 2836 – 2838, 2010

Flegel WA, von Zabern I, Doescher A, Wagner FF, Strathmann KP, Geisen C, Palfi M, Písacka M, Poole J, Polin H, Gabriel C, Avent ND. D variants at the RhD vestibule in the weak D type 4 and Eurasian D clusters. Transfusion 49, 1059 – 1069, 2009

Flegel WA, von Zabern I, Wagner FF. Six years' experience performing RHD genotyping to confirm D– red blood cell units in Germany for preventing anti-D Immunizations. Transfusion 49, 465 – 471, 2009

Lüttringhaus TA, Cho D, Ryang DW, Flegel WA. A simple RHD genotyping strategy for D– East Asian persons applied to Korean blood donors. Transfusion 46, 2128 - 2137, 2006

Wagner FF, Moulds JM, Flegel WA. Genetic mechanisms of Rhesus box variation. Transfusion 45, 338 – 344, 2005

Wagner FF, Poole J, Flegel WA. Scianna antigens including Rd are expressed by ERMAP. Blood 101, 752 - 757, 2003

Wagner FF, Eicher NI, Jørgensen JR, Lonicer CB, Flegel WA. DNB: a partial D with anti-D frequent in Central Europe. Blood 100, 2253 – 2256, 2002

Wagner FF, Ladewig B, Angert KS, Heymann GA, Eicher NI, Flegel WA. DAU allele cluster of the RHD gene. Blood 100, 306 – 311, 2002

Flegel WA, Curin-Šerbec V, Delamaire M, Donvito B, Ikeda H, Jørgensen J, Kumpel B, Le Pennec P-Y, Písacka M, Tani Y, Uchikawa M, Wendel S, Wagner FF. Rhesus index and antigen density: An analysis of the reproducibility of flow cytometric determination (Section 1B: Rh flow cytometry – Coordinator's report). Transf Clin Biol 9, 33 – 42, 2002

Wagner FF, Frohmajer A, Flegel WA. RHD positive alleles in D negative whites. BMC Genetics 2, 10, 2001

Wagner FF, Flegel WA: RHD gene deletion occurred in the Rhesus box. Blood 95, 3662 - 3668, 2000

Wagner FF, Frohmajer A, Ladewig B, Eicher NI, Lonicer CB, Müller TH, Siegel MH, Flegel WA. Weak D alleles express distinct phenotypes. Blood 95, 2699 - 2708, 2000

Flegel WA, Khull SR, Wagner FF. Primary anti-D immunization by weak D type 2 RBCs. Transfusion 40, 428 - 424, 2000

Flegel WA, Besenfelder W, Wagner FF. Predicting a donor's likelihood of donating within a preselected time interval. Transfusion Medicine 10, 181 - 192, 2000

Wagner FF, Gassner C, Müller TH, Schönitzer D, Schunter F, Flegel WA. Molecular basis of weak D phenotypes. Blood 93, 385 - 393, 1999

Wagner FF, Gassner C, Müller TH, Schönitzer D, Schunter F, Flegel WA. Three molecular structures cause Rhesus D category VI phenotypes with distinct immunohematologic features. Blood 91, 2157 - 2168, 1998

Wagner FF, Flegel WA. Polymorphism of the h allele and the population frequency of non-functional alleles. Transfusion 37, 284 - 290, 1997

Wagner, FF, Flegel, WA: Toxic epidermic necrolysis. N Engl J Med 334, 922, 1996

Wagner FF, Flegel WA. Transfusion-associated graft-versus-host disease: risk in transfusions due to homozygous HLA-haplotypes. Transfusion 35, 284 - 291, 1995

Flegel WA, Singson AW, Margolis JA, Bang AG, Posakony JW, Murre C. Dpbx, a new homeobox gene related to the human proto-oncogene pbx1: Molecular structure and developmental expression. Mech Dev 41, 155 - 161, 1993

Kniep B, Flegel WA, Northoff H, Rieber EP. CDw60 antigens of human leukocytes: Structural characterization and cellular distribution. Blood 82, 1776-1786, 1993

Flegel WA, Müller F, Däubener W, Fischer H-G, Hadding U, Northoff H. Cytokine response by human monocytes to Clostridium difficile toxin A and toxin B. Infect Immun 59, 3659 - 3666, 1991

Flegel WA, Wölpl A, Männel DN, Northoff H. Inhibition of endotoxin-induced activation of human monocytes by human lipoproteins. Infect Immun 57, 2237 - 2245, 1989