Fatal asthma attacks unfold in the lungs, where airways narrow, swell and fill with mucus, severely restricting airflow. Yet new research suggests that the immune processes associated with the most dangerous attacks may extend well beyond the chest, involving immune hubs connected to both the lungs and the gut.
A study published in Nature Communications mapped immune activity across multiple organs from hundreds of deceased organ donors. The work provides a detailed look at how immune patterns differ between people who died during an asthma attack, those who had asthma but died from other causes, and people without a recorded history of the disease.
Probing why routine asthma turns deadly
More than 260 million people worldwide live with asthma, and most manage their symptoms with inhalers and other medications. Only a small proportion experience fatal attacks, and understanding what distinguishes these cases remains an important challenge.
Studying immune behavior across numerous tissues simultaneously is extremely difficult in living patients. To address this, immunologists led by Yoonseung Lee and Donna Farber at Columbia University analyzed donated tissues spanning the lungs, blood and multiple lymph nodes.
The researchers examined tissues from 695 organ donors collected in the United States between 2012 and 2025. Of these, 41 died during an asthma attack, 78 had asthma but died from other causes, and 576 had no recorded history of asthma.
Immune signals in the lungs and beyond
One of the clearest signals involved immunoglobulin E, or IgE, an antibody closely involved in allergic responses. In every fatal asthma donor whose IgE levels were measured, concentrations exceeded the usual reference range, pointing to pronounced allergic-type immune activity.
Within the lungs of these donors, researchers found increased numbers of immune cells associated with type 2 inflammation. These included type 2 helper T cells, type 2 innate lymphoid cells and mast cells, which can contribute to airway inflammation and mucus production.
When strongly activated, these cells can intensify inflammation in already narrowed airways. The findings offer clues about the immune environment accompanying fatal asthma, although they do not fully explain why severe attacks become deadly in some people and not others.
A surprising gut-linked immune pattern
Some of the most unexpected findings emerged from lymph nodes, where immune cells coordinate responses. Researchers examined lymph nodes draining the lungs as well as those associated with the gut and other mucosal tissues.
The team found that memory T and B cells accumulated earlier in mucosal-associated lymph nodes of fatal asthma donors than in donors without asthma. These memory cells normally allow the immune system to respond more rapidly to previously encountered threats.
In asthma, environmental allergens such as pollen or dust mites can provoke inappropriate immune responses. A larger pool of memory cells could potentially contribute to faster or more persistent inflammatory responses when relevant triggers are encountered.
At the same time, lymph nodes associated with the lungs contained markedly fewer regulatory T cells, or Tregs, in both groups of donors with asthma. Tregs help restrain immune responses and prevent excessive inflammation.
Because reduced Treg numbers appeared in both asthma groups, the pattern seems to be associated with asthma more broadly rather than specifically with fatal attacks. Together, the findings point to differences in both immune activation and regulation.
What the gut connection really means
An important finding emerged when researchers compared immune-cell patterns across tissues. Among donors who died from asthma, immune populations in the lungs were more closely associated with those in gut-associated lymph nodes than they were among donors without asthma.
This stronger relationship suggests that immune processes associated with fatal asthma may involve coordinated activity across different parts of the body. It raises questions about whether immune events outside the lungs could contribute to conditions that intensify airway inflammation.
Crucially, the study does not show that food, digestive problems or particular gut microbes directly trigger fatal asthma. Researchers examined immune cells in lymph nodes associated with the intestines rather than diet, gastrointestinal symptoms or the gut microbiome itself.
Previous research has linked certain early-life gut microbiome patterns with later asthma risk, particularly in children. The new study adds a different perspective by examining immune-cell organization across multiple tissues in adults.
Limits, open questions and next steps
Because the research was observational and based on organ donors, it can identify associations but cannot establish cause and effect. Each donor provided a single snapshot of immune activity, preventing researchers from determining exactly how the observed patterns developed or whether they preceded the fatal attack.
The fatal asthma group was also relatively small, with 41 donors. Detailed information about corticosteroid treatment, which can substantially influence immune-cell populations, was not available for every case.
Future research could use transcriptomic and spatial-mapping approaches to investigate how specific immune-cell populations interact within different tissues. Studies involving living patients may also help determine whether similar patterns can be detected before severe asthma attacks occur.
For now, the findings do not provide a new diagnostic test or treatment. They do, however, broaden the picture of asthma by showing that immune differences associated with the disease can be detected beyond the airways themselves.
Understanding how lung and gut-associated immune hubs interact could eventually improve researchers’ understanding of severe asthma and help identify new approaches to risk assessment or treatment. Further research will be needed to determine whether modifying these wider immune networks can actually prevent severe or fatal attacks.
