Two types of cytokines responsible for the chronic nature of autoimmune disorders has been identified in a recent study.
Autoimmune disorders affect up to 50 million individuals in the United States. They develop when the body’s immune system begins to attack healthy tissue.
Prior studies have linked Th17 cells–– a subset of T cells––to various autoimmune disorders, including inflammatory bowel disease, multiple sclerosis
, and rheumatoid arthritis
. When Th17 cells are activated, a subset will become memory cells and stay in the body for long periods of time. Eventually, these cells will reactivate and cause flare-ups of the autoimmune condition.
Until now, it was unknown how these Th17 cells maintained memory.
In a study published in the Journal of Autoimmunity
, investigators used a mouse model for dry eye disease to determine which molecular factors were critical for the maintenance of Th17 memory.
“We wanted to know the precise factors that maintain memory in Th17 cells so that we can better understand what is causing chronic autoimmune disorders,” said senior author Reza Dana, MD, MSc, MPH.
The results of the study showed that Interleukin-7 and -16 (IL-7 and IL-15) played a critical role in the survival and homeostatic proliferation of memory Th17 cells. When the investigators neutralized IL-7 and IL-15, they observed a significant reduction in memory Th17 cells.
“By selectively targeting the production and expression of IL-7 and IL-15, we may be able to prevent the development of chronic autoimmune disorders,” Dr Dana said.
The study findings suggest that targeting IL-7 and IL-15 to remove memory Th17 cells could be an effective treatment approach for autoimmune disease. However, the authors noted that more studies are needed to identify different ways to block these factors.
“In the case of dry eye disease, many of the treatments are showing limited efficacy in patients that do not have a highly inflamed eye,” Dr Dana said. “Targeting the chronic, immune nature of autoimmune diseases may be a better strategy for controlling these conditions.”