Harri Alenius

Harri Alenius

Telephone: +46852487015
Visiting address: Nobels väg 13, 17177 Stockholm
Postal address: C6 Institutet för miljömedicin, C6 Systemtoxikologi Alenius, 171 77 Stockholm

About me

  • Harri Alenius is Professor of Molecular Toxicology and Head of the Systems Toxicology Unit at the Institute of Environmental Medicine, Karolinska Institutet.

    He was born in 1966 in Tampere, Finland, and studied Cellular and Molecular Biology at Jyväskylä University, graduating in 1995. He got PhD in Tampere University in 1997. He conducted research at the Finnish Institute of Occupational Health (FIOH) from 1996–2016 and appointed as Research Professor in 2005. Alenius was a postdoc at Children’s Hospital, Harvard Medical School from 1998–2000.

    On August 2016, he was appointed as a full Professor of Molecular Toxicology at Karolinska institutet. Alenius is also chairman of the expert panel of SweNanoSafe - the national platform for nanosafety.


  • My research interest is to investigate how different environmental exposures affect human wellbeing, focusing on the impact of chemicals, allergens and microbes on immunity. I am particularly interested in how environmental toxicants and microbiota (the ecosystem of microorganisms) and human microbiota interact with each other, and how they affect the immune system and contribute health and disease.

    I am leading and participating in several projects, focusing on the impact of host-microbiome interplay during immune homeostasis and dysregulation. My research combines data derived from the human cohorts and clinical studies with experiments on cell and animal models. Bioinformatics analysis, such as 16S and metagenomic approaches, and their integration with environmental exposure data, clinical data and other OMICs layers are applied in my research.

    The major ongoing projects are briefly described below.

    Project 1: Host-microbe interactions in atopic dermatitis and psoriasis

    The two most common chronic inflammatory skin diseases are atopic dermatitis (AD) and psoriasis. The underpinnings of the remarkable degree of clinical heterogeneity of AD and psoriasis are poorly understood and, as a consequence, disease onset and progression are unpredictable and the optimal type and time-point for intervention are as yet unknown. The BIOMAP project (https://biomap-imi.eu) is the first IMI (Innovative Medicines Initiative) project dedicated to investigating the causes and mechanisms of AD and psoriasis and to identify potential biomarkers responsible for the variation in disease outcome. There is mounting evidence supporting an important role for microbial exposures and our microbiota as factors mediating immune polarization and AD and psoriasis pathogenesis. Therefore, the aim of the work package WP4 is to investigate skin and gut microbiome linked to AD or psoriasis. The BIOMAP project will enable the integration of patient cohorts, data and knowledge in unprecedented proportions. The project has a unique opportunity with a potential to bridge and fill the gaps between current problems and solutions.

    The project is done in collaboration with docent Nanna Fyhrquist as well as with BIOMAP and MAARS consortium members. The project is funded by the IMI2 - Innovative Medicines Initiative.

    Project 2: Karelia Allergy Study

    The biodiversity hypothesis suggests that reduced exposure to diverse environmental microbes has resulted in the current increase in chronic inflammatory diseases, including allergy, in western societies. However, the mechanistic basis of the association between microbial diversity, faulty immune programming, and the risk of allergic disease remains largely unknown.

    After the Second World War, populations living in the Karelia area were strictly divided by the border between Finland and Russia. This resulted in the evolution of starkly different lifestyles, standard of living and exposure to environmental microbes. The key finding of our previous study from Karelia was that allergic symptoms and diseases were dramatically more common in Finnish children and adults than in their Russian counterparts.

    The Karelia Allergy Study cohort provides a unique opportunity to explore the role of the human microbiota in the development of allergy as well as in immune homeostasis. Taking advantage of this exceptional study cohort, state-of-the-art OMICs methodologies and systems biology approaches we explore environment-gene interaction and molecular mechanisms underlying allergy protection and allergic sensitization.

    The project is done in collaboration with docent Nanna Fyhrquist as well as with prof.emer Tari Haahtela and Karelia Allergy Study -team. The project is financed by the Swedish Research Council (Vetenskaprådet – Medicine and health).

    Project 3: The role of host microbiota in chemically induced metabolic disruption

    Increase in metabolic impairment correlates with industrialization and release of xenobiotic chemicals to the environment and the food chain. Dysbiosis of the gut microbiota is another risk factor of metabolic impairment. Although several environmental pollutants have shown to alter the gut microbiota, little is known regarding the link between chemical exposure, microbiota dysbiosis and impaired metabolic function.

    We hypothesise that the interaction between xenobiotic chemicals and gut microbiota pose a critical mode of action (MoA) for metabolic disruption.

    In this project we aim to: a) determine the impact of xenobiotic chemicals on the gut microbiota
  • b) investigate the effect of microbiota on host physiology in response to chemical exposure in gnotobiotic model and c) identify MoA underlying the link between chemically induced microbiota dysbiosis and metabolic disruption

    Our proposal relies on the analysis of microbiota-host interactions, utilizing zebrafish embryo models to interrogate the effect of environmental pollutants on biological processes associated with metabolic disorders. We will identify key effect markers underlying metabolic disruption that can be utilized to establish an efficient and biologically relevant screening platform to interrogate metabolic disruptive potencies of environmental pollutants.

    The project is done in collaboration with docent Emma Wincent and her group members. The project is financed by the Swedish Research Council for Sustainable Development (FORMAS).

Selected publications


All other publications


  • Professor, Institute of Environmental Medicine, Karolinska Institutet, 2024-

Degrees and Education

  • PhD, Tampere University, 1997

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