As health officials warn the public to stop using e-cigarettes, researchers may finally decide what vaping leads to life-threatening lung disease.

On Friday, the Centers for Disease Control and Prevention announced that various state health departments had reported more than 450 cases of “severe pulmonary disease associated with e-cigarette products” and five confirmed deaths.

‘Oily Droplets’ in the Lungs

Also released Friday, the research, led by investigators at the University of Utah Health and published in the New England Journal of Medicine, identified large immune cells containing numerous oily droplets, called lipid-laden macrophages, within the lungs of vaping patients.

By the deadline for data submission for publication, the authors had found lipid-laden macrophages in six out of six cases seen at the University of Utah Hospital in Salt Lake City. Since publication, that number has risen to ten out of ten.

Researchers used bronchoalveolar lavage to uncover the macrophages, which gather at infection sites and clean up debris. This report marks the first time a clinician has pinpointed this characteristic.

Expanding Diagnostic Strategies

“These cells are very distinctive, and we don’t often see them,” said senior author Scott Aberegg, MD, a critical care pulmonologist at the University of Utah Health, in a statement. “That made everybody start to think carefully about why they were there. Are they scavenging debris in the lungs that were introduced through vaping?”

Until now, to diagnose a vaping-related respiratory illness, providers have relied primarily on the patient’s history of vaping and excluding known causes of similar conditions. For example, a patient’s lung scans may indicate serious viral or bacterial pneumonia, but tests for both will return negative.

A test for lipoid pneumonia in the first University of Utah Health vaping patient prompted this NEJM submission. After researchers found lipoid pneumonia’s lipid-laden macrophages marker in the patient, they performed bronchoalveolar lavage in several others they believed had a vaping-related illness. All were positive.

A New Type of Lipoid Pneumonia?

So, is the vaping-related illness lipoid pneumonia? It’s unclear. While most vaping illnesses have appeared in teens and young adults, classic lipoid pneumonia is most common in older people because it’s typically caused by accidentally breathing in oil-based laxatives. The two conditions also present differently in lung x-rays.

That said, the vaping illness could potentially be a new type of lipoid pneumonia, researchers say.

“We need to determine if these cells are specific for the illness or whether they are also seen in vaping patients who are not ill and don’t have symptoms,” Aberegg explained. “If they are only seen in patients who get sick, we can begin to make some connections between what we’re seeing in the lipid-laden macrophages and whatever components of the vaping oils may be causing this syndrome.”

What To Know About Vaping-Related Lung Disease

Aberegg and the team are breaking new ground as the Food and Drug Administration and CDC struggle to find a definitive device or substance behind the illness. CDC officials have said with some confidence that there’s no sign of infectious disease in the patients, and the culprit is likely chemical exposure.

Preliminary research is starting to indicate the condition is most common in patients who vape nicotine and THC, followed by those who vape only THC, and those who vape just nicotine being the smallest group.

At this stage in the investigation, the CDC urges clinicians to report possible cases of vaping-related pulmonary disease to their local and state health departments. If you encounter one, take a detailed history of substances and devices the patient used and the source. If you can, obtain any remaining vaping liquid or devices in case the CDC wants to coordinate testing them.