The Invisible Kingdom: Reimagining Chronic Illness

by Meghan O'Rourke

As she put it, the microbiome (whether in our gut or in other organs and tissues or, indeed, in our mouth) and our immune system are like a kindergarten class and a teacher. The class is orderly when the teacher—the immune system—is present. But if the teacher leaves the room (in this case, to fend off a virus), the normally well-behaved pupils get unruly, and the biome may misbehave. Now everyone is drawn into the bad activity, releasing chemical signals that almost appear to egg others on. As she noted, “P. gingivalis is the biggest cavity-driving pathogen. A lot of people have it in their mouth, and they are fine. But if your immune system isn’t great, and fails to monitor it, P. gingivalis starts to produce biofilm-signaling molecules, and neighboring organisms are like, wait, we can join a biofilm?” (Biofilms are slimy structures inside of which bacteria live in an organized community and communicate with one another; the spongy molecular matrix that contains them helps protect them from the immune system’s attacks.) And soon you’ve got a mouth full of cavities.