This study is misguided....! The researchers have failed to demonstrate that this good bacteria plays a major role in causing Crohn's....! They have also ignored the fact that it's the infection with a bacterium, such as MAP, that may be causing this lack of response to the good bacteria, yet they mention it themselves that these very genes predispose to infection.....It's like trying to treat a wound without taking out a splinter......Besides, if healthy humans depend so much on this good bacteria, then killing this good bacteria (such as occurs with long-term antibiotic use) would cause Crohn's even with protective genes, but this obviously doesn't happen....! This study also doesn't explain why Crohn's rates have skyrocketed since 1930s.....