It takes a few minutes for anaphylaxis to set in, and a quarter to half an hour to kill you if left untreated. Anaphylaxis is an allergic reaction that rapidly leads to a severe drop in blood pressure and constricts the airway. Insect stings, any medication, and even peanuts can trigger it, and the window to save the victim is very narrow. While existing treatments buy some time and can even be life-saving, they can only be used to intervene after anaphylaxis has already been triggered. On the contrary, a fecal transplant, or fecal microbiome transplant, might increase tolerance towards a certain allergen, which can reduce the incidence of anaphylaxis.
Fecal Transplant Showed Success
A fecal transplant is mainly used to improve gut microbiota by transferring gut bacteria harvested from the stool samples of healthy donors. It is heralded as one of the best, if not the best, treatment options for recurrent C. difficile infections. However, the procedure is also being studied as a way to treat a multitude of issues, ranging from irritable bowel syndrome to autism.
A study published in Science Translational Medicine reports that six people who were highly allergic to peanuts can now tolerate them after receiving a fecal transplant. The trial, however, included a small cohort of 15 people. Cathryn Nagler, an immunology researcher at the University of Chicago in Illinois, is excited that the technique has now gone beyond mouse models and has been tried out in people. Nagler also believes that the results are remarkable.
Before taking part in the study, participants could tolerate only 100 milligrams of peanut protein, amounting to less than half a peanut, without triggering an allergic reaction. Four months post-transplant, the participants were able to consume between 300 and over 600 milligrams, the equivalent of about two and a half peanuts.
Not many treatment options are available for food allergies. The standard advice for people is to avoid exposure to the allergen and carry an EpiPen— an adrenaline injection to administer if an anaphylactic attack occurs. The fecal transplant does something to address the elephant in the room: A cure for the allergic response. Peanut and shellfish allergies are often lifelong, and the transplant benefits the patients by increasing their tolerance for them and reducing attacks if accidentally exposed.
Food Allergies Kept in Check
Managing to keep a healthy gut microbiota usually supports better overall physical and mental health. Some research has linked food allergies with the scarcity of certain gut bacteria. Research in mice also suggests that the animals with groups of several gut bacteria kept food allergies in check. Researchers speculated that fecal transplants from people without any food allergies might contain a broader range of gut bacteria, which can desensitize the immune system in people with an allergy to some extent.
Researchers gave an odorless and tasteless pill containing gut bacteria from healthy volunteers without a peanut allergy in the new trial. Most participants were given 36 pills in a single day, which didn’t create any serious side effects. Five of the participants were also put on a four-day course of antibiotics prior to the transplant.
While six people saw an improvement, nine people didn’t respond to the treatment, which the authors believe happened because the bacteria might not have become established yet. The scientists point to gender-related differences (five of the six people who responded were men). Other potential factors might be that the bacteria weren’t delivered on a single day, and that most of the people who didn’t respond also didn’t receive antibiotics before the treatment.
The researchers also transplanted gut bacteria from the participants’ stool samples into mice. The bacteria from people who responded to the treatment also prevented allergies to an egg protein in mice. Mice that received bacteria from people who remained sensitive didn’t provide such protection to egg protein. The mouse study suggests that the fecal transplant treatment can work for more than just peanut allergies, says study co-author Talal Chatila, an immunologist at Harvard Medical School in Boston, Massachusetts.
One specific bacterial species caught the scientists’ attention: Bacteroides ovatus, which protected the mice from developing an allergy. Identifying a specific bacterial species that makes the immune system less reactive is “the holy grail of food allergy,” according to Chatila. Although the scientists have achieved significant success, it would still take about a decade for the bacteria to be approved by regulators.
Right now, the authors are looking forward to starting a second, larger trial once they finish with enrolments. The next trial will provide more clues to which other bacteria might have a positive effect on the people. This trial will give almost 12 times the dose of gut bacteria in the first trial, spread out over a month.
Never Again, EpiPen
“What we’re hoping for is that the microbiome modulation can lead to a point where you will not need your EpiPen [adrenaline injection] anymore, and you’ll be able to eat some amount of peanut,” says study co-author Rima Rachid, an immunologist at Harvard Medical School.
EpiPen is the difference between life and death in case of an anaphylactic attack. When Mylan acquired the product in 2007, an EpiPen twin-pack cost just $100. The price kept swelling year-on-year after that, and in 2016, prices soared to $600 for a twin-pack despite the cost of the core medicine remaining low. Notably, then CEO Heather Bearsch received a major pay hike during the same period.
Public outrage followed, and ultimately, after a congressional hearing, the company rushed to release a generic version at a cut price. On top of that, they endured multi-million-dollar class-action settlements. Despite all that, the price of an EpiPen hovers around $700 without insurance, particularly because the maker holds key patents on the auto-injector tool.
While at-risk groups regularly need to keep the life-saving drug handy in case of an allergic reaction, the success of fecal transplant in addressing food allergies, which can last a lifetime, is something to be excited about.
Copyright @smorescience. All rights reserved. Do not copy, cite, publish, or distribute this content without permission.
