While atopic dermatitis (AD) is often treated with therapies that produce immunosuppression, a group of researchers have discovered that strengthening part of the immune system—the number of natural killer (NK) cells in the body—may represent a viable treatment approach as well. In a paper published in Science Translational Medicine (Feb. 26, 2020; 12(532):eaay1005), researchers from the Washington School of Medicine in St. Louis note they have observed that patients with AD have a deficiency of NK cells in their blood consistently enough that the team uses NK levels as a diagnostic aid. They also found that NK levels rose as AD was treated.
Dr. Brian S. Kim examines eczema patient Casey Richards. Video by: Washington School of Medicine
“We were perplexed as to why [AD patients had low levels of NK cells in their blood], but the numbers were low enough, consistently enough, that eventually we started using them almost like a diagnostic tool,” said principal investigator Dr. Brian S. Kim, a dermatologist and an associate professor of medicine at the school, in a press release. “If we had any doubt about whether a person had eczema, we would take a blood sample and look at their NK cell levels.”
To further test this observation, the team used a mouse model of AD. Removing the ability of the animals to produce NK cells worsened their AD symptoms. Subsequently treating the mice with an investigational medication to increase NK counts resulted in a reduction in inflammation and AD symptoms.
“If you look at the skin of the mice we studied, their eczema resolves in a way we haven’t seen before with other therapies,” said Dr. Kim. “And so far, our mouse model of eczema has accurately predicted what we will see in patients.”
Dr. Kim said he believes that in addition to improving skin rash associated with AD, boosting the numbers of NK cells could help restore virus immunity in AD patients, noting that people who have very low numbers of NK cells tend to be more susceptible to the herpes virus, pox viruses and HPV viruses, among others.
Investigational medications that increase NK cell populations are being tested as treatments for some types of cancer in clinical trials at Siteman Cancer Center at Barnes-Jewish Hospital in St. Louis and Washington University School of Medicine. Dr. Kim said those studies suggest the medications selectively boost NK cells, so he is now working with researchers from Siteman to test them in a clinical trial targeting AD.
“We have a patent pending for this strategy, and we are planning to move toward trials,” he said. “And we will not limit our studies to eczema. This strategy could help patients who have asthma or food allergies, conditions that often appear along with eczema.”