Gunnar Nilsson group

Head of division, PhD, Professor

Gunnar Nilsson got his PhD degree in immunology from Uppsala University in 1989. He moved on to a postdoctoral position with Dr. Lawrence B. Schwartz, Medical College of Virginia, Richmond, VA where he was part of the seminal finding of stem cell factor as an essential growth and differentiation factor for human mast cells. He returned to Uppsala University in 1992 where he set up his own research group at the department of pathology. Between 1994-1996 he was a guest scientist with Dr. Dean Metcalfe, Laboratory of Allergic Diseases, NIAID, NIH, Bethesda, MD. Since 2003 he is working at the Karolinska Institutet, Stockholm, where he is PI for a group on mast cell biology. He is member of several international and national organizations. He has published more than 150 scientific articles, mainly within the area of mast cell functions in health and disease.

Group Gunnar Nilsson and Team Joakim Dahlin

Mast Cell Biology Group

Anna-Karin Johnsson, Jiezhen Mo, Elin Rönnberg Höckerlind, Daryl Zhong Hao Boey, Gunnar Nilsson, Chenyan Wu, Joakim Dahlin

Group members

Maria Ekoff

Affiliated to Research

Maria did her undergraduate studies in Molecular Biotechnology at Uppsala University. She received her PhD in Immunology at the department of Medicine at Karolinska Institutet in 2008 and thereafter did post doctoral training at the Institute of Environmental Medicine, Karolinska Institutet. She returned to the department of Medicine in 2014 as a senior lab manager for the mast cell Group.

Joakim Dahlin

Principal Researcher

Joakim did his undergraduate studies in Molecular Biotechnology Engineering at Uppsala University. In 2013, he received his PhD in medical sciences from the Department of Medical Biochemistry and Microbiology, Uppsala University. He continued his research at the same department until 2015, when he started as a postdoctoral fellow in professor Gunnar Nilsson’s Group.

Elin obtained her master in biology in 2008 at Uppsala University. In 2014, she received her PhD in medical biochemistry at the department of anatomy, physiology and biochemistry at the Swedish university of agricultural sciences. She continued her research in the same group until 2016 when she started as a postdoc in Gunnar Nilsson’s Group.

Anna-Karin did her undergraduate studies in Biomedicine at Uppsala University and then completed her PhD at the dept. of Cell Biology, Stockholm University in 2011. She continued to do a post doc in cell signaling at the Babraham Institute in Cambridge UK after which she started at the Karolinska Institutet with mast cell research in 2018. She joined the group as a senior lab manager in 2021.

Chenyan Wu

Affiliated to Research

Chenyan did her undergraduate study in Clinical Medicine at Southern Medical University and got her Master’s degree in Oncology in 2018 at Sun Yat-sen University in China. She started with a CSC-KI funded PhD position at Karolinska Institutet in 2018.

Daryl Zhong Hao Boey

Phd Student;Clinical Assistant

Daryl graduated from the MTLS Masters programme (KI/KTH/SU) affiliated with SciLifeLab, Sweden in 2019. His previous educational background includes a Bachelors in Biomedical Science from the University of Western Australia.
Daryl is currently employed as a Research Assistant studying the transcriptional landscape of hematopoietic differentiation.

Jiezhen Mo

Postdoctoral Researcher

Jiezhen did her undergraduate study at Wuhan University in 2014 and obtained her PhD degree from Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences in July 2020. She started as a Postdoc at Karolinska Institutet in 2021.

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Theo Gulen

Affiliated to Research

Theo is specialist in internal medicine, clinical immunology and allergology and currently serves as a consultant physician in the Respiratory Diseases and Allergy clinic, Karolinska University Hospital, Huddinge. He received his PhD from the Karolinska Institutet in 2014 on a project on clonal mast cell disorders and anaphylactic reactions. His current research focuses on mast cell activation disorders to characterize patient phenotypes and mechanisms leading to this uncontrolled mast cell activation.

Yitao Gong

Phd Student

Cristina Iribarren graduated in biological sciences (Bc) from Complutense University of Madrid and specialized in medical immunology (Ms) from University of Barcelona. In 2022, she received her PhD degree in medical sciences from the University of Gothenburg (Sweden). Thereafter, she worked as associate researcher in the same group. In November 2022, Cristina started as postdoctoral researcher at Karolinska Institutet.


Andrea Teufelberger, did her undergraduate studies in Molecular Biology (BSc) and Biochemistry and Molecular Biomedicine (MSc) at Graz University in Austria. Thereafter, she studied the immunological response mechanisms towards a bacterial allergen in a murine model of allergic asthma at Ghent University in Belgium, where she obtained her PhD in Health Sciences in 2018. Since November 2018 Andrea has been a postdoc in Gunnar Nilsson’s group.

Systemic Mastocytosis
Identification of novel biomarkers for anaphylaxis and immune tolerance in mastocytosis

Anaphylaxis is a life-threatening, systemic allergic reaction. Patients with systemic mastocytosis have a significantly higher risk of experiencing an anaphylactic shock than the general population. Our overall goal is to better understand mechanisms of anaphylaxis and immune tolerance to improve treatment options that can prevent anaphylaxis in the future. We screen for specific diagnostic and prognostic biomarkers of anaphylaxis and immune tolerance in mastocytosis patients. Further, we study the molecular mechanisms underlying the altered protein levels of the identified biomarkers. Understanding these regulatory mechanisms might help to find better treatment options for mastocytosis patients as well as for anaphylactic patients without a clonal mast cell disease.

Selected publications

Divergent Effects of Acute and Prolonged Interleukin 33 Exposure on Mast Cell IgE-Mediated Functions.
Rönnberg E, Ghaib A, Ceriol C, Enoksson M, Arock M, Säfholm J, et al
Front Immunol 2019 ;10():1361

Single-cell analysis reveals the KIT D816V mutation in haematopoietic stem and progenitor cells in systemic mastocytosis.
Grootens J, Ungerstedt JS, Ekoff M, Rönnberg E, Klimkowska M, Amini RM, et al
EBioMedicine 2019 May;43():150-158

An Optimized Protocol for the Isolation and Functional Analysis of Human Lung Mast Cells.
Ravindran A, Rönnberg E, Dahlin JS, Mazzurana L, Säfholm J, Orre AC, et al
Front Immunol 2018 ;9():2193

Mast cell-dependent IL-33/ST2 signaling is protective against the development of airway hyperresponsiveness in a house dust mite mouse model of asthma.
Zoltowska Nilsson AM, Lei Y, Adner M, Nilsson GP
Am. J. Physiol. Lung Cell Mol. Physiol. 2018 03;314(3):L484-L492

Histone deacetylase inhibitor SAHA mediates mast cell death and epigenetic silencing of constitutively active D816V KIT in systemic mastocytosis.
Lyberg K, Ali HA, Grootens J, Kjellander M, Tirfing M, Arock M, et al
Oncotarget 2017 Feb;8(6):9647-9659

Assessment of in vivo mast cell reactivity in patients with systemic mastocytosis.
Gülen T, Möller Westerberg C, Lyberg K, Ekoff M, Kolmert J, Bood J, et al
Clin. Exp. Allergy 2017 Jul;47(7):909-917

KIT signaling is dispensable for human mast cell progenitor development.
Dahlin JS, Ekoff M, Grootens J, Löf L, Amini RM, Hagberg H, et al
Blood 2017 10;130(16):1785-1794

Detection of circulating mast cells in advanced systemic mastocytosis.
Dahlin JS, Ungerstedt JS, Grootens J, Sander B, Gülen T, Hägglund H, et al
Leukemia 2016 09;30(9):1953-6

The interleukin-33 receptor ST2 is important for the development of peripheral airway hyperresponsiveness and inflammation in a house dust mite mouse model of asthma.
Zoltowska AM, Lei Y, Fuchs B, Rask C, Adner M, Nilsson GP
Clin. Exp. Allergy 2016 Mar;46(3):479-90

Vaccination against IL-33 Inhibits Airway Hyperresponsiveness and Inflammation in a House Dust Mite Model of Asthma.
Lei Y, Boinapally V, Zoltowska A, Adner M, Hellman L, Nilsson G
PLoS ONE 2015 ;10(7):e0133774

Interleukin-33 exacerbates allergic bronchoconstriction in the mice via activation of mast cells.
Sjöberg LC, Gregory JA, Dahlén SE, Nilsson GP, Adner M
Allergy 2015 May;70(5):514-21

Knockdown of the antiapoptotic Bcl-2 family member A1/Bfl-1 protects mice from anaphylaxis.
Ottina E, Lyberg K, Sochalska M, Villunger A, Nilsson GP
J. Immunol. 2015 Feb;194(3):1316-22

Flushing, fatigue, and recurrent anaphylaxis: a delayed diagnosis of mastocytosis.
Gülen T, Hägglund H, Dahlén SE, Sander B, Dahlén B, Nilsson G
Lancet 2014 May;383(9928):1608

Intraperitoneal influx of neutrophils in response to IL-33 is mast cell-dependent.
Enoksson M, Möller-Westerberg C, Wicher G, Fallon PG, Forsberg-Nilsson K, Lunderius-Andersson C, et al
Blood 2013 Jan;121(3):530-6

Mast cells increase vascular permeability by heparin-initiated bradykinin formation in vivo.
Oschatz C, Maas C, Lecher B, Jansen T, Björkqvist J, Tradler T, et al
Immunity 2011 Feb;34(2):258-68

Mast cells as sensors of cell injury through IL-33 recognition.
Enoksson M, Lyberg K, Möller-Westerberg C, Fallon PG, Nilsson G, Lunderius-Andersson C
J. Immunol. 2011 Feb;186(4):2523-8

Mast cell CD30 ligand is upregulated in cutaneous inflammation and mediates degranulation-independent chemokine secretion.
Fischer M, Harvima IT, Carvalho RF, Möller C, Naukkarinen A, Enblad G, et al
J. Clin. Invest. 2006 Oct;116(10):2748-56

Stem cell factor promotes mast cell survival via inactivation of FOXO3a-mediated transcriptional induction and MEK-regulated phosphorylation of the proapoptotic protein Bim.
Möller C, Alfredsson J, Engström M, Wootz H, Xiang Z, Lennartsson J, et al
Blood 2005 Aug;106(4):1330-6

Aktiverad mastcell

Research focus

Mast cells are (in)famous for their role as effector cells causing the symptoms in allergy and anaphylactic chock. However, we don’t have mast cells to cause problems for us but to protect us. They are an essential part of our host defense system, sensing both endogenous and exogenous “danger signals”, and react to these by initiating an inflammatory response. Mast cells have a unique capacity to recognize different molecules and to react to these by releasing specific sets of mediators. Given the great capacity to release powerful mediators, such as histamine proteases, lipid mediators and cytokines, mast cells are also associated with a number of different diseases, where these cells and their mediators are part of the pathology. Examples of diseases where mast cells are involved are asthma, chronic inflammatory skin diseases, cancer and systemic mastocytosis. The focus for our research is to understand the role of mast cells in health and disease and to study regulatory mechanisms for mast cell activation and mediator release.

Aktiverad mastcell


Systemic Mastocytosis - Theo Gülen, Joakim Dahlin, Katarina Lyberg, Jennine Grootens

Systemic mastocytosis (SM) is a rare and sometimes fatal disorder, in which the mast cell lineage development is dysfunctional. The disease is associated with an accumulation of mast cells in the body and symptoms caused by the release of mast cell mediators. The long-term goal is to find markers that have a prognostic value for the disease, as well as to identify specific targets that can be used for clinical therapeutic interventions. Several projects are ongoing:

Identification of dysfunctional regulatory pathways in SM
Investigation of developmental checkpoints in the mast cell lineage that might be corrupted.
Identification of biomarkers that can be used for diagnostic and/or prognostic purposes.
Studies of risk factors for the development of anaphylaxis

Regulatory functions of microRNAs in mast cells

In this project we study microRNA-based regulatory mechanisms underlying mast cell-activating diseases. The main objective is to identify microRNAs and their target genes regulating mast cell functions, including growth and reactivity. The project is conceived with two specific aims:

1) To identify genes and pathways regulated by identified microRNAs in mast cells

2) To evaluate plasma microRNAs as biomarkers and diagnostic tools in mast cell-activating diseases

MicroRNAs belong to a big class of small, non-coding RNAs that regulate gene expression by targeting mRNAs for translational repression and/or degradation. These molecules are emerging as important modulators of cellular pathways such as growth, proliferation, apoptosis and inflammatory responses. Mast cell activation occurs in a variety of acute and chronic inflammatory states, playing an important role in the pathogenesis of several different types of diseases. Some of these diseases, such as allergy, asthma, anaphylaxis, urticaria and mastocytosis, are particularly associated with mast cell activation and the symptoms are related to mast cell mediators, and in some cases hyperplasia. However, the etiology and why mast cells are prone to be activated are for many of these diseases not fully deciphered. One area that has attracted a lot of attention recently is the role of microRNA in regulating cellular functions and the use of circulating miRNAs as biomarkers. However, the current knowledge about the role of microRNAs) in regulating mast cell functions is very limited.


Role of interleukin-33 in the development and exacerbation of allergic asthma – Ying Lei, Anna Nilsson

The airway epithelium is considered an essential controller of inflammatory immune responses to allergens, viruses and environmental pollutants that contribute to asthma pathogenesis. Recent experimental and clinical studies have implicated the novel epithelial cells-derived cytokines interleukin-33 (IL-33) in the pathogenesis of respiratory allergy and asthma. The interactions between IL-33 and mast cells and type 2 cytokine–producing innate lymphoid cells (ILC2s) could be promising therapeutic targets for allergic asthma. We sought to investigate the interplays between mast cells, ILC2 cells and IL-33, and their contribution to allergic lung responses by applying our asthma models in both wild type and genetically modified mice. The long-term goal of the study is to translate the conclusions from our well-established in vivo models to subjects with asthma.

Human lung mast cell heterogeneity – Joakim Dahlin, Avinash Ravindran

Lung mast cells are infamous for their devastating role in allergic asthma. Human mast cells are classically divided into two distinct subsets based on their expression of the proteases chymase and tryptase. In this project we further explore the heterogeneity of human lung mast cells, with the ultimate goal to find the characteristic subset of the mast cells causing asthma exacerbations.

The interaction between innate lymphoid cells of type 2 and mast cells in allergic airway inflammation – Avinash Ravindran

Both mast cells and innate lymphoid cells of type 2 have an important role for the development of allergic airway inflammation. The focus of this project is to study the interaction between mast cells and innate lymphoid cells of type 2, and its implication for acute and chronic airway inflammation.

Activation pathways and mast cell mediators

Inhibition of mast cell activation responses – Maria Ekoff

The main focus of this project is to identify substances with the ability to inhibit mast cell release of inflammatory mediators. Mast cells are long-lived effector cells of the immune system perhaps best known for their involvement in allergic diseases. Upon activation, the mast cell releases a variety of inflammatory substances (histamine, leukotrienes, proteases and cytokines) that cause the symptoms we associate with allergy. Today allergy is treated primarily with anti-histamines, i.e. treating the symptoms rather than the cause. A more direct approach would be to prevent/reduce mast cell release. Since mast cell mediators also play a part in many inflammatory diseases, this approach could be used as a novel strategy for treatment also in these settings. A more long-term goal is to perform large scale screenings to find substances or combinations thereof to reduce/abolish mast cell activation. Effective candidate-substances are then tested more extensively in vitro, ex vivo (biopsies) and in vivo using animal models.

Content reviewer:
Annika Jouper