News archive

The notion that some level of microbial exposure might reduce our risk of developing allergies has arisen over the last few decades and has been termed ‘the hygiene hypothesis'. Now, an article published in Science Immunology by researchers from Karolinska Institutet challenges this hypothesis by showing that mice with high infectious exposures from birth have the same, if not an even greater ability to develop allergic immune responses than 'clean' laboratory mice.

The government has appointed Jan Albert, professor of infectious disease control at Karolinska Institutet and senior consultant at Karolinska University Hospital, to lead a government inquiry looking into strengthening the country’s preparedness for future pandemics. The directive concerns a national strategy for how pandemics are to be managed and a possible revision of the Communicable Diseases Act. The investigation should be delivered in February 2025.

A new study led by researchers at Karolinska Institutet has examined how T cells of the immune system are affected by weightlessness. The results, which are published in the journal Science Advances, could explain why astronauts’ T cells become less active and less effective at fighting infection.

Vaccination protects against severe COVID-19 but not against infection. Researchers at Karolinska Institutet and Danderyd Hospital now show that protection against infection with the new omicron variants is linked to mucosal IgA antibodies, which are not induced by vaccination. These are the findings of two studies recently published in The Lancet Infectious Diseases, and The Lancet Microbe, and could explain the limited protection by currently available vaccines against infection.

A new study in Nature by an international team including researchers at Karolinska Institutet has identified the first genetic variant associated with disease severity in multiple sclerosis. The finding opens the door to the development of treatments that fight disease progression – a great unmet need facing people with MS.

Assistant professor Marcus Buggert at Karolinska Institutet is awarded Anders Jahre's prize for young researchers 2023 and 400.000 NOK.

Our skin contains specialised long-lived killer cells that protect against intruders. Researchers at Karolinska Institutet and the University of Copenhagen have now identified how these cells are formed, and shown that high levels of memory killer cells in cancer tissue correlate with a better survival rate in people with melanoma. The study is published in the journal Immunity.

Jenny Mjösberg at the Department of Medicine in Huddinge at Karolinska Institutet, receives the 2023 Eric K. Fernström Prize for young, promising and successful researchers, for her outstanding research on the role of innate lymphoid cells in various diseases.

Vaccines against smallpox given until the mid-1970s offer continuing cross-reactive immunity to mpox (previously known as monkeypox), researchers from Karolinska Institutet report in a study published in the scientific journal Cell Host & Microbe.

Researchers at Karolinska Institutet have found further evidence for how the Epstein-Barr virus can trigger multiple sclerosis or drive disease progression. A study published in Science Advances shows that some individuals have antibodies against the virus that mistakenly attack a protein in the brain and spinal cord.

Researchers from Karolinska Institutet and Sachs’ Children and Youth Hospital have mapped the immune system in the gut of children with inflammatory bowel disease (IBD). The results, which were published in Cell Reports Medicine, can be used to design more targeted therapies.

Acetylcholine regulates blood flow, but the source of blood acetylcholine has been unclear. Now, researchers at Karolinska Institutet have discovered that certain T cells in human blood can produce acetylcholine, which may help regulate blood pressure and inflammation. The study, which is published in PNAS, also demonstrates a possible association between these immune cells in seriously ill patients and the risk of death.

Immunotherapy is an effective form of therapy for different types of cancer. However, for pancreatic cancer, its effect is limited and differs between men and women. Researchers at Karolinska Institutet have now found a possible explanation for this sex difference. The study, which is published in Cancer Research, reveals the presence of an immune cell in women with pancreatic cancer that obstructs the body’s immune response. The results can pave the way for a more sex-specific treatment.

During the pandemic, it became clear that children who contracted COVID-19 became less ill than adults. One hypothesis has been that common colds would give children immunity protecting against a severe form of the disease. Researchers at Karolinska Institutet are now able to show that OC43, one of the coronaviruses that cause common colds, boosts the immune response to COVID-19. The study, which is published in PNAS, could give rise to more tailored vaccine programmes for children and adults.

Jenny Mjösberg, Professor of Tissue Immunology at Karolinska Institutet, is one of five researchers to be awarded the Göran Gustafsson Prize this year. The prize is intended for young researchers in medicine, molecular biology, chemistry, physics and mathematics and is awarded by the Göran Gustafsson Foundations in collaboration with the Royal Swedish Academy of Sciences.

The first detailed description of the microbiota and immune cells among asymptomatic Helicobacter pylori-infected individuals has been published by researchers at Karolinska Institutet. The results of the study will be instrumental to understand the complex microbiome and immunity network and provide new insights for asymptomatic Helicobacter pylori infection.

PhD student Pradeepa Pushparaj, in Gunilla Karlsson Hedestam’s group at the Department of Microbiology, Tumor and Cell Biology, is the first author of a study recently published in Immunity. The study explains how antibody genes can influence the ability to make neutralizing antibodies to SARS-CoV-2.

High levels of mucosal IgA antibodies in the airways protect against SARS-CoV-2 infection for at least eight months. Omicron infection generates durable mucosal antibodies, reducing the risk of re-infection. These are the findings of a study published in The Lancet Infectious Diseases by researchers at Karolinska Institutet and Danderyd Hospital in Sweden. The results raise further hope for the feasibility of future nasal vaccine platforms to protect against infection.

Nano-sized membrane bubbles known as extracellular vesicles activate the immune system in mice and seem to render their tumours sensitive to a type of immunotherapy drug called a checkpoint inhibitor. This is according to a new study published in Cancer Immunology Research by researchers at Karolinska Institutet.

The nanomaterial graphene oxide—which is used in everything from electronics to sensors for biomolecules—can indirectly affect the immune system via the gut microbiome, as shown in a new study on zebrafish by researchers at Karolinska Institutet. The findings are reported in the journal Nature Nanotechnology.

B cells are critical to the proper functioning of the immune system. However, researchers at Karolinska Institutet have shown that they can sometimes do more harm than good, as their numbers greatly increase after bowel damage, preventing the tissue from healing. The results, which are presented in the journal Immunity, can be of significance to the treatment of inflammatory bowel disease.

By measuring immune cells in the cerebrospinal fluid when diagnosing ALS, it is possible to predict how fast the disease may progress according to a study from Karolinska Institutet published in Nature Communications.

Researchers at Karolinska Institutet have shown that patients with acute COVID-19 infection have increased levels of the cytokine IL-26 in their blood. Moreover, high IL-26 levels correlate with an exaggerated inflammatory response that signifies severe cases of the disease. The findings, which are presented in Frontiers in Immunology, indicate that IL-26 is a potential biomarker for severe COVID-19.  

The Committee for Research at Karolinska Institutet has decided on recipients from the Jonas Söderquist scholarship foundation for basic research in virology and immunology 2022. Quirin Hammer at the Department of Medicine, Huddinge (MedH) and Daniel Sheward at the Department of Microbiology, Tumor- and Cell Biology (MTC)) are awarded.

Four research projects coordinated from Karolinska Institutet have been awarded project grants by Knut and Alice Wallenberg Foundation (KAW) in 2022. This means that, over SEK 135 million are allocated to KI research in the fields of immunology, neuroscience, and stem cell biology.

A study at Karolinska Institutet shows that the coronavirus variant BA.2.75.2, an Omicron sublineage, largely evades neutralizing antibodies in the blood and is resistant to several monoclonal antibody antiviral treatments. The findings, published in the journal The Lancet Infectious Diseases, suggest a risk of increased SARS-CoV-2 infections this winter, unless the new updated bivalent vaccines help to boost immunity in the population.

Lower immunity and recurring infections are common in type 1 and type 2 diabetes. Researchers at Karolinska Institutet now show that the immune system of people with diabetes has lower levels of the antimicrobial peptide psoriasin, which compromises the urinary bladder’s cell barrier, increasing the risk of urinary tract infection. The study is published in Nature Communications.

In a new analysis, Karolinska Institutet is ranked number eight in a list of organizations with the most published articles on COVID-19 and the immune response. KI also stands out as one of the universities that has had the most international collaborations in the field. The analysis was conducted by Chinese researchers without a connection to KI and is published in the journal Frontiers in Public Health.

Researchers at Karolinska Institutet present the results of a refined clinical COVID-19 test, which has been used to track the spread of the Omicron variant in real time in the Swedish population. The study, published in the journal Med, provides new insights into the dominance transition of Omicron sublineages that occurred consistently across the world.

The clinical outcome and severity of COVID-19 cannot be explained by a single factor like age, gender, or comorbidities. A new study from Karolinska Institutet in Sweden has identified potential determinants of COVID-19 severity at the cellular level using advanced systems biology analysis. The findings, published in the journal Cell Systems, offer insights into the metabolic tug-of-war in the human body and its association with disease severity.

Researchers at Karolinska Institutet and Danderyd Hospital have followed participants who have received three doses of the SARS-CoV-2 vaccine and compared their immune responses after Omicron infection. The results, which are published in The Lancet Infectious Diseases, show that Omicron infection elicits significantly higher antibody responses in individuals without prior COVID-19 infection as compared to previously infected individuals.

The nervous system is known to communicate with the immune system and regulate inflammation in the body. Researchers at Karolinska Institutet now show how electrical activation of a specific nerve can promote healing in acute inflammation. The finding, which is published in the journal PNAS, opens new ways to accelerate resolution of inflammation.

Researchers at Uppsala University and Karolinska Institutet are one step closer to explaining why COVID-19 patients have a substantially increased risk of blood clots. The study, published in Nature Immunology, shows that a gene variant in the innate immune system influences the risk for blood clots in the lungs of severely ill COVID-19 patients.

Researchers at Karolinska Institutet have mapped how the parasite Trypanosoma cruzi forms new variants that are more effective at evading the immune system and causing disease. Their findings can give rise to new methods for diagnosing, preventing and treating Chagas disease, which affects millions of people in Central and South America, causing thousands of deaths every year. The study is published in the journal eLife.

Currently available therapies to treat multiple sclerosis (MS) lack precision and can lead to serious side effects. Researchers at KI have now developed a method for identifying the immune cells involved in autoimmune diseases, and have identified four new target molecules of potential significance for future personalised treatment of MS. The results, which are published in Science Advances, have been obtained in collaboration with KTH Royal Institute of Technology and Region Stockholm.

By analysing samples from patients who have been treated for malaria in Sweden, researchers at Karolinska Institutet can now describe how the immune system acts to protect the body after a malaria infection. The results, published in the journal Cell Reports, provide knowledge that can aid in the development of more effective vaccines against the disease.

Researchers at Karolinska Institutet have identified key signalling pathways that when blocked by existing drug candidates limit reproduction of the Crimean-Congo haemorrhagic fever (CCHF) virus. The findings, published in the journal eLife, offer hope for patients affected by this potentially deadly disease.

Researchers at Karolinska Institutet have developed a novel strategy for identifying potent miniature antibodies, so-called nanobodies, against emerging SARS-CoV-2 variants. The approach led to the discovery of multiple nanobodies that in cell cultures and mice effectively blocked infection with different SARS-CoV-2 variants. The findings, which are described in the journals Nature Communications and Science Advances, could pave the way for new treatments against COVID-19.

Late last year, preliminary studies revealed that the fast-spreading Omicron SARS-CoV-2 variant was likely to evade COVID-19 antibodies but, in many people, less so than expected. Now one of those studies from Karolinska Institutet has been published in the prestigious journal The Lancet Infectious Diseases. KI researcher Ben Murrell explains the findings and recalls the rush to understand the new variant.

There is a lack of understanding as to why some people suffer from long-lasting symptoms after COVID-19 infection. A new study from Karolinska Institutet in Sweden, the Helmholtz Center Munich (HMGU) and the Technical University of Munich (TUM), both in Germany, now demonstrates that a certain type of immune cell called macrophages show altered inflammatory and metabolic expression several months after mild COVID-19. The findings are published in the journal Mucosal Immunology.

Little has been known to date about how the immune system’s natural killer (NK) cells detect which cells have been infected with SARS-CoV-2. An international team of scientist led by researchers from Karolinska Institutet now shows that NK cells respond to a certain peptide on the surface of infected cells. The study, which is published in Cell Reports, is an important piece of the puzzle in our understanding of how the immune system reacts to COVID-19.

The omicron variant can partly evade the antibody response provided by vaccination or infection with previous variants of SARS-CoV-2. However, T cells still recognise omicron, scientists at Karolinska Institutet report in a study published in the journal Nature Medicine.

From our first breath, our lungs are exposed to microorganisms, such as bacteria and viruses. Thanks to immune cells in the lungs, so-called macrophages, we are protected from most infections at an early age. In a new study published in the Journal of Experimental Medicine, researchers from Karolinska Institutet show how lung macrophages develop; new findings that can help to reduce organ damage and that are significant for the continued development of important lung disease treatments.

KI researcher Marcus Buggert has been awarded the prestigious ERC Starting Grant for his research on human cell-mediated immunity against virus diseases. In all, the European Research Council through this call will invest EUR 619 million in 397 young research leaders.

Instead of searching for proteins that the immune system reacts against in a specific autoimmune disease, researchers have taken the opposite approach to find diseases linked to a certain protein. By searching among patients with various skin diseases, they identified a disease linked to autoimmunity against the skin protein TGM1. The strategy, which is presented in the journal PNAS, can facilitate the diagnosis and treatment of autoimmune diseases.

Researchers at Karolinska Institutet report that a recently discovered inflammatory mediator, interleukin-26, appears to have an important role in pneumonia and contribute to the killing of bacteria. The study is published in the scientific journal Frontiers in Immunology - Microbial Immunology.

Researchers at Karolinska Institutet have analysed the presence of SARS-CoV-2-specific antibodies and memory cells of the immune system in young adults. The results, published in The Journal of Allergy and Clinical Immunology, show that over one in four had antibodies due to the infection. Fewer of these individuals had measurable levels of memory B and T cells compared with other age groups. The researchers will now study long COVID in young adults and the effects of vaccination on immunity.

Antibodies in the airways quickly wane after SARS-CoV-2 infection, but vaccination results in a strong increase in antibody levels, especially after two doses, according to a new study from Karolinska Institutet published in the journal JCI Insight. The results suggest that having a second dose of vaccine also after recovering from COVID-19 may be important for protecting against re-infection and to prevent transmission.

COVID-19 disease severity seems to be affected by the characteristics of white blood cells called granulocytes, which are part of the innate immune system. Combined measurements of granulocytes and well-known biomarkers in the blood can predict the severity of the disease, according to a new study from Karolinska Institutet. The results are published in the journal PNAS and may eventually contribute to more tailored treatments for COVID-19 patients.

Our bodies can fine-tune the immune response to an infection and make it proportional to the threat at hand. New research from Karolinska Institutet describes how B lymphocytes, the immune cells that make antibodies, choose between different cell fates to balance the magnitude of the acute immune response and the memory response that protects against future threats. The study, published in Immunity, may contribute to the optimisation of vaccines to fight viruses or other pathogens.