Using CAR T Cell Therapy to Treat Asthma in Mice

Using genetically modified cells to kill abnormal immune cells that trigger asthma attacks could be an effective treatment for the most common type of asthma, according to a study in mice.

But making this type of treatment affordable is a major challenge, and given the risks, it will probably only be offered to patients suffering from life-threatening asthma attacks.

“For most asthma patients, inhalers will suffice, but about 250,000 people die from severe asthma each year,” he said. Min Peng At Tsinghua University, Beijing, China.[This] This may be an option for those patients.”

Asthma is a condition in which the airways become swollen and narrow, making it difficult to breathe. Asthma attacks can be triggered by factors such as allergies or air pollution.

Most cases of asthma involve a process called a type 2 immune response, which is meant to defend the body against parasites such as worms, but can lead to an excess of immune cells called eosinophils. Inhaled steroids usually suppress this response and reduce symptoms, but people with severe asthma may need regular injections of antibodies designed to reduce the number of eosinophils.

It is possible to genetically engineer immune cells called T cells to kill specific cell types. These modified cells, called CAR T cells, are primarily used to treat certain cancers, but have also been used to treat the autoimmune disease lupus.

Now, Peng and his colleagues have engineered CAR T cells that kill eosinophils. In mice with induced type 2 asthma, a single injection of these cells prevented symptoms for up to a year, the same period the experiment lasted. “In mice, these cells persist indefinitely in the body,” Peng says.

CAR T cells can cause deadly side effects when used to treat cancer, but Peng's team saw no such side effects in mice, suggesting the treatment is safer. They also saw no signs that the CAR T cells would turn cancerous. But the team said that if the treatment is approved for asthma patients, each cell should be engineered with a “kill switch” just to be safe.

But the process of extracting, modifying, and replacing cells from the body required to generate CAR T cells is extremely expensive. Approved CAR T therapies cost about $400,000 in the U.S., and the total cost, including all medical costs, is $1.2 billion. It could be higher.

“For common diseases like asthma, affordability is key to making CAR T cells available to the vast majority of patients,” says Peng, who hopes that it will be possible to convert cells in the body directly into CAR T cells without extracting them, which would significantly reduce costs.