The meibomian gland obstruction associated with chronic allergic eye disease is likely caused by immune cells, according to a new study. The finding could lead to more effective therapies for a common condition that lacks treatment options largely because the underlying causes are not well understood.
The study, led by researchers at the Duke Eye Center, used both an established preclinical model of allergic eye disease (AED) and samples from human patients to demonstrate an immune etiology for meibomian gland dysfunction (MGD).
“This study shows that some forms of MGD are inflammatory diseases, and our studies in mice confirm what we see in the tears of people with blocked glands,” says Duke ophthalmologist Preeya K. Gupta, MD, a co-author of the study published July 25 in Science Translational Medicine. “This pathway may be a new target for therapeutic agents to help treat patients suffering from dry eye disease and MGD.”
Using the AED mouse model, the researchers showed that T-cell–mediated neutrophil recruitment causes MGD. Data from the human study further supported a role for neutrophils in the pathogenesis of MGD: Neutrophil cell number in tear fluid was positively correlated with clinical MGD severity. Elevated neutrophils were most common in people with severe MGD who also had conditions causing inflammation, including allergies, rosacea, and autoimmune diseases.
“In addition to providing new treatment strategies, the presence of neutrophils in the eye could provide a biomarker to detect the disease or measure its severity,” says Daniel R. Saban, PhD, senior author of the study and associate professor of ophthalmology at Duke.
The authors stress that there are different causes for MGD, and not all are related to inflammation from allergies or autoimmune conditions. Conversely, not all inflammation in the eye leads to blockages in the glands. But for the majority of people with MGD and allergic eye disease, the findings could be a clue to more effective treatments.
“New treatments might be presented sooner than expected,” Saban says. “The market is robust right now for new drugs that can modulate the immune system. With the new understanding of how immune cells are involved in this condition, the findings could be translatable with a drug that’s already on the market and repurposed for relieving MGD.”