There has been evidence that gut flora has a role in allergies for some years now. But this is the first study I've seen wherein some of the important bacteria (various clostridium species) were identified. And also the first where colonizing the subjects' (mice) GI tracts actually caused a reversal of allergy symptoms (for peanut allergies, specifically).
Of course, this was an animal study and not a new treatment approved for humans, but it's encouraging nonetheless.
Here is an abstract of the study itself: