Some Types of Asthma Protect Against Severe COVID-19, And We May Finally Know Why

People with chronic lung conditions like asthma were anxious about the severity of the disease when it first began. We might finally understand why people with some types of asthma are faring better than expected.

Population-based studies in Australia, the UK and Europe, and the United States have found no evidence that asthma causes severe symptoms of COVID-19.

It is the opposite. People with asthma are less likely to get sick after catching the disease, compared to people with other lung conditions.

Researchers at the University of North Carolina at Chapel Hill think they have figured out what distinguishes asthma patients.

The team used cell cultures from the human respiratory tract. Some of the samples were treated with a small molecule known to be more prevalent in asthma. Its presence causes asthmatics to produce more mucus than healthy levels.

They got the cell cultures to have the disease. There were many more infections in the cells that were treated with IL-13.

We knew there had to be a bio-mechanistic reason why people with allergic asthma were more protected from severe disease.

Our research team discovered a number of significant cellular changes, particularly due to IL-13, which led us to conclude that IL-13 plays a unique role in defense against the disease.

Ehre and her colleagues noticed when they watched the respiratory cells and the virus interact under an electron microscope that IL-13 treatments increased the mucus produced by the respiratory cells.

The cells still showed a degree of protection even after the mucus was removed.

The presence of IL-13 in the cell culture was found to be upregulating genes linked to the antiviral properties, while downregulating the expression of cell receptors that coronaviruses are known to attach to.

The coronaviruses are able to invade relatively easily in respiratory cells. Researchers noticed that if a cell was really sick, it was more likely to shed away from the airway surface, allowing it to fall deeper into the lungs.

The authors conclude that the intense viral and cell shed caused by the disease was mitigated by the effect of IL-13.

IL-13 can be used as a treatment, but not alone. It is part of the immune response and can cause inflammation in the airway.

Understanding the details of what is happening in the lungs is important. Some of the underlying mechanisms behind severe COVID-19 cases have been highlighted by scientists by comparing cells that mimic asthmatic airways to healthy airway cells.

In the future, therapeutic drugs could be used to target sites that are more involved in severe symptoms.

Ehre says that the research shows how important it is to treat the disease as early as possible.

It shows how important specific mechanisms are, as we try to protect patients from developing severe infections.

The study was published in a journal.