When Immune Cells Attack

But some scientists believe Th-17’s role in disease has been overestimated. Lawrence Steinman, an immunologist at Stanford University, says he is not sold on the idea that tinkering with Th-17 is a cure-all for autoimmune diseases. He cites the small number of human Th-17 studies, along with mouse studies that he says have yielded mixed results concerning Th-17’s importance.

“[Scientists] hailed Th-17 as the master mediator of tissue damage, but they will realize that Th-17 was not as important as originally described,” says Steinman. He compares the flurry of research on Th-17 to the story of “The Emperor’s New Clothes.” Scientists, he says, ignore results that contradict Th-17’s role in tissue damage, such as a study published in March in the Journal of Immunology that indicated Th-17 may actually combat inflammation, not cause it. “People take a look at the emperor and say, ‘That’s a lovely suit of clothes,’” when there really aren’t data — or, in other words, the emperor is naked, says Steinman.

Even scientists with strong faith in Th-17’s role in autoimmune diseases caution that tinkering with levels of the cell is a difficult task with potential health risks. That’s because Th-17 is closely related to other immune cells in function and development, so halting the manufacture of only one of them requires extensive knowledge of the way each cell behaves and replicates. And scientists don’t want to eliminate too many Th-17 cells because, when they function correctly, they play a vital role in the body’s immune response. “There is a delicate balance between [Th-17 cells] fighting potentially dangerous pathogens, and causing pathology by themselves,” says Marc Veldhoen, an immunologist investigating Th-17 cell development and function at the National Institute for Medical Research in London. Therefore, although overabundance of Th-17 can be harmful, without it the body is more susceptible to disease.

Still, many scientists remain confident that investigating Th-17 will someday lead to a reliable treatment for devastating autoimmune diseases. And given the volume of research on Th-17 underway, it seems unlikely that interest in the cell will fade anytime soon. In the end, only experimental results can prove whether Th-17 is really the key to treating for autoimmune diseases. “Show me the data,” says Stanford’s Steinman. “The wonderful thing about science is that data finally win the game.”