BOSTON—In the early 1990s, immunologists thought there were just two types of helper T cells—Th1 and Th2—which, while not by themselves damaging, could activate other effector cells to promote disease. However, discoveries in last few years have proven that the T-cell world is actually much more diverse.
By 2000, researchers had discovered a third class of helper T cells that called into question everything known about Th1 and Th2. Surprisingly, these new cells—named Th17 because they secrete a cytokine called interleukin 17 (IL-17)—have some cytotoxic properties. Most interesting for rheumatologists, Th17 cells can display specificity for self-antigens, making them a crucial component of the development of inflammation and severe autoimmunity.
The history, developmental properties, and potential therapeutic targets of Th17 cells were discussed by Daniel Cua, PhD, a researcher at Schering-Plough Biopharma/DNAX in Palo Alto, Calif., at the ACR/ARHP Annual Scientific Meeting in Boston last November. He also presented new data, published in the December issue of Nature Immunology (2007;8:1390-1397), showing how specific cellular environments can lead to the pathogenic properties of Th17 cells.
“There’s so much work on Th17 cells coming out now, and so fast,” Dr. Cua said. “It’s really changing the way immunologists think about inflammatory diseases.”