Bartosz Grzywacz, MD

Assistant Professor, Department of Laboratory Medicine and Pathology

Bartosz Grzywacz

Contact Info

Office Phone 612-273-5464

Office Address:
D223 Mayo Memorial Bldg.

Mailing Address:
MMC 609 Mayo
8076A (Campus Delivery Code)
420 Delaware St. SE
Minneapolis, MN 55455

Wroclaw Medical University, Poland, 1998-1999

Lower Silesian Centre for Cellular Transplantation, Internship, 1999-2001

Lower Silesian Centre for Cellular Transplantation , Residency (Internal Medicine), 2001-2005

University of Wisconsin (Anatomic and Clinical Pathology), 2009-2013

Cleveland Clinic (Hematopathology), 2013-2014

Pomeranian Medical University, Poland, 1992-1998


Dr. Grzywacz is a hematopathologist whose research interests include the development, normal function, and diseases involving natural killer (NK) cells as well as their therapeutic potential. NK cells are specialized lymphocytes of the innate immune system that possess some of the cell memory capabilities characteristic of cells found in the adaptive immune system. They originate in the bone marrow and lymph nodes and are important effector cells for anti-tumor immunity.

Grzywacz was part of a team that developed an in-vitro system for producing NK cells from hematopoietic stem cells and human embryonic stem cells. NK cells produced through this process bore biomarkers associated with potent cell-killing activity and are equipped to attack and clear tumor cells. Grzywacz’s research with Michael Verneris, Jeffrey Miller and others on the development of NK cells using an in-vitro system revealed that these cells may be derived from myeloid developmental pathway. Some human CD34+ hematopoietic stem cells develop into NK cells when stimulated by the several cytokines including interleukin-7, interleukin-15, and stem cell factor. Grzywacz and his colleagues were able to define the conditions under which myeloid precursor cells tend to produce NK cells and found that NK cells produced through this process possess high levels of cytotoxicity. More recently investigators found that some of the cells thought to be NK cell precursors that failed to differentiate into mature NK cells constitute a novel innate lymphoid cell type.

Research interest in NK-cell origin, function and potential enhancement of NK cells for tumor immunotherapy is part of a wave of interest in immunotherapy based on significant advances in the field in the past decade. Grzywacz plans to renew his studies of NK cells from the point of view of pathology in three ways: NK-cell use in immunotherapy; the role of NK cells in cancers other than hematologic malignancies; and lymphoid malignancies that originate from NK cells including aggressive neoplasms associated with Epstein-Barr virus infection.

Professional Associations

  • College of American Pathologists
  • American Society for Clinical Pathology
  • European Federation for Immunogenetics
  • Polish Society for Immunogenetics (founding member)
  • Society for Natural Immunity
  • American Society of Hematology
  • Society For Hematopathology - SH 
  • American Association for the Study of Liver Disease AASLD
  • United States and Canadian Academy of Pathology USCAP 



  • Weinberg OK, Chisholm KM, Ok CY, Fedoriw Y, Grzywacz B, Kurzer JH, Mason EF, Moser KA, Bhattacharya S, Xu M, Babu D, Foucar K, Tam W, Bagg A, Orazi A, George TI, Wang W, Wang SA, Arber DA, Hasserjian RP Clinical, immunophenotypic and genomic findings of NK lymphoblastic leukemia: a study from the Bone Marrow Pathology Group.
    Modern Pathology. 2021 Feb 01. doi:10.1038/s41379-021-00739-4, 10.1038/s41379-021-00739-4
  • Obeid KM, Grzywacz B, Ferrieri P, Arbefeville S, Slungaard A, Betts B. Hemophagocytic lymphohistiocytosis induced by Toxoplasma gondii infection diagnosed by a bone marrow biopsy and DNA next-generation sequencing in an allogeneic hematopoietic stem cell transplant recipient. Transpl Infect Dis. 2021;:e13610. doi:10.1111/tid.13610, 10.1111/tid.13610
  • Amy K. Erbe, Wei Wang, Lakeesha Carmichael, Anna Hoefges, Bartosz Grzywacz, Patrick K. Reville, Erik A. Ranheim, Jacquelyn A. Hank, KyungMann Kim, Songwon Seo, Eneida A. Mendonca, Yiqiang Song, Vaishalee P. Kenkre, Fangxin Hong, Randy D. Gascoyne, Elisabeth Paietta, Sandra J. Horning, Jeffrey S. Miller, Brad Kahl, and Paul M. Sondel.Follicular lymphoma patients with KIR2DL2 and KIR3DL1 and their ligands (HLA-C1 and HLA-Bw4) show improved outcome when receiving rituximab.J Immunother Cancer. 2019; 7: 70. doi: 10.1186/s40425-019-0538-8
  • Gilles SR, Yohe SL, Linden MA, Dolan M, Hirsch B, Grzywacz B. CD161 Is expressed in a subset of T-cell prolymphocytic leukemia cases and Is useful for disease follow-up.Am J Clin Pathol. 2019 Sep 9;152(4):471-478. doi: 10.1093/ajcp/aqz060.
  • Grzywacz B, Moench L, McKenna D Jr, Tessier KM, Bachanova V, Cooley S, Miller JS, Courville EL.  Natural killer cell homing and persistence in the bone marrow after adoptive immunotherapy correlates with better leukemia control.  J Immunother. 2018 Nov 28. doi: 10.1097/CJI.0000000000000250. [Epub ahead of print]
  • Kityo C, Nganou Makamdop K, Rothenberger M, Chipman J G, Hoskuldsson T, Beilman GJ, Grzywacz B, Mugyenyi P , Ssali Rama Akondy F, Anderson J, Schmidt T, Reimann T, Callisto S, Schoephoerster J, Schuster J, Muloma N, Ssengendo P, Moysi E, Petrovas C, Lanciotti RS, Zhang L, Arevalo MT, Rodriguez B, Ross T, Trautmann L, Sekaly RP, Lederman M, Koup R, Ahmed R, Reilly C, Douek D, Schacker T. “Lymphoid tissue fibrosis is associated with impaired vaccine responses” J Clin Invest. 2018 Jul 2;128(7): 2763-2773.
  • Rothenberger M, Wagner JE, Haase A, Richman D,Grzywacz B, Strain M, Lada S, Estes J, Fletcher CV, Podany AT, Anderson J, Schmidt T, Wietgrefe S, Schacker T, Verneris MR Transplantation of CCR5?32 Homozygous Umbilical Cord Blood in a Child With Acute Lymphoblastic Leukemia and Perinatally Acquired HIV Infection.Open Forum Infect Dis. 2018 May 22;5(5). doi:10.1093/ofid/ofy090 
  • Sundin A,Grzywacz B, Yohe S, Linden MA, Courville EL. B-cell posttransplant lymphoproliferative disorder isolated to the central nervous system is Epstein-Barr virus positive and lacks p53 and Myc expression by immunohistochemistry.Hum Pathol. 2017 Mar;61:140-147. PMID: 27993575,
  • Ondrejka SL, Grzywacz B, Bodo J, Makishima H, Polprasert C, Said JW, Przychodzen B, Maciejewski JP, Hsi ED. Angioimmunoblastic T-cell Lymphomas With the RHOA p.Gly17Val Mutation Have Classic Clinical and Pathologic Features. Am J Surg Pathol. 2016 Mar;40(3):335-41. doi: 10.1097/PAS.0000000000000555.
  • Bachanova V, Frankel AE, Cao Q, Lewis D, Grzywacz B, Verneris MR, Ustun C, Lazaryan A, McClune B, Warlick ED, Kantarjian H, Weisdorf DJ, Miller JS, Vallera DA. Phase I study of a bispecific ligand-directed toxin targeting CD22 and CD19 (DT2219) for refractory B-cell malignancies.
    Clin Cancer Res. 2015 Mar 15;21(6):1267-72. doi: 10.1158/1078-0432.CCR-14-2877.
  • Koehn TA, Trimble LL, Alderson KL, Erbe AK, McDowell KA, Grzywacz B, Hank JA, Sondel PM. Increasing the clinical efficacy of NK and antibody-mediated cancer immunotherapy: potential predictors of successful clinical outcome based on observations in high-risk neuroblastoma. Front Pharmacol. 2012 May 16;3:91. doi: 10.3389/fphar.2012.00091.
  • Grzywacz B., Kataria N.K., Kataria N., Blazar B.R., Miller J.S., and Verneris M.R.  2011. Natural Killer cell differentiation by myeloid progenitors. Blood 117(13):3548-58.
  • Grzywacz, B., J.S. Miller, and M.R. Verneris. 2008. Use of natural killer cells as immunotherapy for leukaemia. Best Practice & Research in Hematology 21:467-483.
  • Grzywacz, B., N. Kataria, and M.R. Verneris. 2007. CD56 (dim) CD16 (+) NK cells downregulate CD16 following target cell induced activation of matrix metalloproteinases. Leukemia 21:356-359.


Board Certifications

American Board of Pathology, Anatomical and Clinical Pathology, 2013