Bartosz Grzywacz

Associate Professor


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.

Research Summary



MD, Wroclaw Medical University, Poland, 1998-1999

Fellowships, Residencies, and Visiting Engagements

Cleveland Clinic (Hematopathology), 2013-2014,
Lower Silesian Centre for Cellular Transplantation , Residency (Internal Medicine), 2001-2005,
University of Wisconsin (Anatomic and Clinical Pathology), 2009-2013,
Lower Silesian Centre for Cellular Transplantation, Internship, 1999-2001,



D218 Mayo Building
420 Delaware St SE
Minneapolis, MN 55455