Niklas Björkström group - Human tissue-resident NK cells

Our group performs translational immunological research studying tissue-resident natural killer cells in the human liver and uterus.

The Niklas Björkström group

A key focus of the group is to gain insights into the basic biology of tissue resident NK cells in liver and uterus. Through unique collaborations with clinical units at the Karolinska University Hospital, we receive a high number of tissue samples. With respect to the uterus, key questions of interest include detailed characterization of the uterine NK cell KIR receptor repertoires, functional studies of uterine tissue resident NK cells, as well as trying to elucidate the ontogeny of uterine NK cells. In the liver we have a specific focus on human tissue-resident CD49a+ intrahepatic NK cells and study their phenotype, function, development, and role during liver diseases.

Moreover, we have an interest in the role of natural killer (NK) cells in the pathogenesis of liver diseases such as primary sclerosing cholangitis, steatohepatitis (NASH), and hepatitis virus infections (HBV, HCV, HDV). These diseases strongly predispose for tumor development in the human liver and we are also performing tumorimmunological studies evaluating the capacity of NK cells to recognize hepatocellular carcinoma and cholagiocarcinoma. Outside the liver, we also have an interest in NK-cell function during hemorrhagic fever virus infections.

Our studies include phenotypic and functional assessments of NK cells with a focus on differentiation, education, and functional and transcriptional regulation. We work with high-dimensional 22-parameter flow cytometry, CyTOF, microscopy techniques, and new tools for visualization and analysis of highly complex flow cytometry data including SPADE, SNE, and Citrus.

We function in close collaboration with other groups at Karolinska Institutet, including groups at the Center for Infectious Medicine. We participate in Karolinska Institutet - Hannover Medical School exchange program, in the International PSC Study Group.

Group leader

Niklas Björkström

Group Leader, MD PhD, Associate Professor

Niklas received his M.D. and Ph.D. degrees from Karolinska Institutet in 2011. He completed postdoctoral training at the National Institutes of Health (Bethesda, Maryland, USA). Niklas established an independent laboratory at CIM, Karolinska Institutet in 2013 and is an associate professor at Karolinska Institutet since 2016. His research focuses on human tissue-resident NK cells with a particular emphasis on uterine and liver NK cells. In his spare time he enjoys fly fishing and playing golf.

Group members

Martin Cornillet

PhD, Research Coordinator

Martin finished his PhD in 2014 that concerned the study of specific autoantibodies in Rheumatoid arthritis (Toulouse, France). He is now focusing on the development of Mass Cytometry to analyse immune cells, and particularly NK-cell phenotype and function in different contexts relating to liver physiology/pathophysiology. He likes cooking, practicing sports (karate, tennis, football) and is interested in art and music discovering.

Lena Berglin

PhD, Senior Laboratory Manager

Lena obtained her PhD from Karolinska Institutet in 2015. During her research studies, her main focus was to try to understand how the immune system contributes to the pathogenesis of primary sclerosing cholangitis (PSC) and bile duct cancer. She is specialized within the field of immunohistochemistry and quantitative image analysis, techniques that she now assists other group members with, as well as collaborators outside the group. In her spare time she likes to be in the countryside, to cook and to read crime novels.

Martin Ivarsson

PhD, Assistant Professor

Martin received his PhD from Karolinska Institutet in 2014. After conducting postdoctoral studies at University of Cambridge, UK, Martin has returned to CIM and is now Assistant Professor. He focuses on studying uterine immune cells in healthy women, in women undergoing IVF and in different pregnancy disorders. When not at work, he enjoys spending time with his family or to go for a run.

Meredith Sun

PhD, bioinformatician

Meredith Sun completed her PhD in bioinformatics in 2019 at the Georgia Institute of Technology, focusing on integrating genetic, transcriptomic, and epigenetic data analysis to investigate sex chromosome evolution in birds. After graduation, she worked as a bioinformatician in the bioinformatics service core at MD Anderson cancer center, where she was involved in multiple projects, including how B cells could contribute to anti-tumor immunity. At CIM, she will perform omics data analysis of patient samples in collaboration with other researchers. In her spare time, she enjoys reading novels and listening to science podcasts.

Iva Filipovic

PhD, Postdoctoral Fellow

Iva completed her MSc in Immunology at Imperial College London where she studied NK cell development. She then went on to complete a PhD at the University of Cambridge in the field of reproductive immunology, with a particular focus on phenotypic and transcriptomic characterisation of tissue-resident innate lymphocytes in the uterus. She now continues to pursue her research interests in studying the roles of tissue-resident NK cells in the context of uterine and liver microenvironments in homeostasis and pathology. When not at work, Iva enjoys fitness, music and photography.

Christopher Maucourant

PhD, Postdoctoral Fellow

Christopher received his Master Degree in immunology and cancerology in 2016. He completed his PhD in 2019 at Sorbonne University in Paris, France, in the field of the signaling pathways involved in NK cells during different arbovirus infections. During his postdoctoral studies, he will characterize tissue-resident NK cells from multiple human tissues, as well as studying the immune response during liver cirrhosis. When not at work, Christopher enjoys athletics (competition at national and international level), cooking, playing piano and to travel.

Benedikt Strunz

MD PhD, Postdoctoral Fellow

Benedikt graduated 2014 as a MD and additionally accomplished a Bachelor's degree in Biology (University of Tuebingen, Germany). He did his PhD-studies in our group focusing on NK cells in viral infections as well as on uterine NK cells and defended in 2020. Now he is combining postdoctoral work in the group with training in clinical microbiology. In his spare time he likes sports like cross country skiing and rowing, enjoys music and jazz concerts and he loves the cinema.

Natalie Stiglund

MD, PhD-student

Natalie received her M.D. from Karolinska Institutet in 2016 and is currently a PhD-student. She is studying the role of NK-cells in fatty liver disease and development of steatohepatitis and hepatocellular carcinoma. In her spare time, she enjoys playing tennis, reading, and travelling.

Jonna Bister


Jonna received her MD from Karolinska Institutet in 2018 and is currently a PhD-student. She is studying uterine NK cell development as well as factors regulating KIR repertoire formation in the uterus. In her spare time Jonna enjoys travelling and go to restaurants.

Emma Patey

PhD Student

Emma received her integrated Masters degree in Immunology from the University of Glasgow in 2020. Her Masters placement at Institut Pasteur involved understanding the role of epigenetic modifications on host-pathogen interactions. She is studying the cellular ontogeny of innate lymphocytes seeding peripheral tissues in murine models, and will later focus on understanding the role of NK cells in the human uterus in the context of pregnancy. In her free time, Emma enjoys socializing with friends, hiking and eating in restaurants.

Daniel Geanon


Daniel earned his Bachelor's degree in Biology and Global Health at Washington University in St. Louis in 2017. More recently, he worked as an Associate Researcher at Mount Sinai's Human Immune Monitoring Center in New York, New York. There, he focused on leveraging systems level immune profiling technologies (i.e. CyTOF, scRNA-seq) in a diverse range of translational research projects, from profiling tumor infiltrating lymphocytes in cancer to peripheral blood immunophenotyping in COVID-19 and MIS-C. At Karolinska Institutet, his studies will focus on tissue resident T and NK cells in inflammatory diseases, as well as contributing to KI's ongoing COVID-19 research effort. In his freetime, Daniel enjoys playing football and spending time outdoors hiking and cycling.

Corinna Mayer


Corinna earned her Master’s degree in Biomedicine at Karolinska Institutet in 2021. Her MSC thesis project was bout the expression and function of CD96 (Tactile) on uterine NK (uNK) cells, supervised by Martin Ivarsson. As a PhD student she profiles uNK cells from patients undergoing IVF treatment and patients suffering from neutropenia which allows her to tackle questions about the outcome of pregnancies, and the role of neutrophils on uNK cells. Besides projects focusing on reproductive immunology, Corinna works on COVID-19 related projects as well. In her spare time, she likes being outside, spending time with family and friends and eating good food, especially pastries.

Katharina Schott

Research assistant

Katharina Schott is in charge of biobanking cells from uterine tissues that are instrumental for several projects. In addition she is involved in various experimental work. In her free time, she enjoys travelling, being out in nature and baking.

Andrea Ponzetta

PhD, Team Leader

In 2014 Andrea completed his PhD in Immunology at Sapienza University of Rome, where he focused on NK cell trafficking and development. He then moved as a postdoctoral fellow to Humanitas Clinical and Research Center in Milan to study the role of neutrophils in carcinogenesis in solid tumors and their interaction with unconventional T cells. At CIM since 2020, he is currently interested in the biology of innate-like lymphocytes and in their impact in human tumors. When not at work, Andrea enjoys travelling, cooking and hiking.


Open positions

We are constantly looking for exceptionally talented post docs with an ambition to explore new and unique aspects of human NK cells, liver immunology, and related questions. Contact Group leader: Niklas Björkström (

Previous members

  • Sanna Nyström, now postdoc at University of Tokyo
  • Kimia Maleki, master-student, now PhD-student at Karolinska Institutet
  • Sebastian Lunemann, now postdoc at University Medical Center Hamburg-Eppendorf
  • Julia Hengst, now Production Manager at Miltenyi Biotech
  • Erik Bergquist, now MD-student at Karolinska Institutet
  • Otto Strauss, now working in Medical Affairs in Rare Diseases at Pfizer in London. 
  • Christine Zimmer, now working at Glaxo Smith Kline, Germany, but will soon proceed with postdoctoral studies.
  • Isabella Sönnerborg now Physician at Kalmar Regional Hospital
  • Laura Hertwig, now Flow Operations Technical Lead at Covance, Genève
  • Ann-Charlotte Elkan, previously PhD, Research nurse, now retired