Researchers at the RIKEN Center for Integrative Medical Sciences in Japan, led by Hiroshi Ohno, found that the bacteria in our gut may affect how well oral immunotherapy works for milk allergies. They found that the likelihood of a successful course of treatment could be raised by a particular kind of beneficial bacteria known as Bifidobacterium. Better oral immunotherapy therapies may result from this discovery; probiotic supplements may be included.
Gut bacteria are thought to help reduce allergic reactions to some foods, but little is known about the link between these bacteria and oral immunotherapy for milk allergy. Consequently, the RIKEN IMS team evaluated 32 kids who were allergic to cow’s milk and were receiving oral immunotherapy; the initial month of the study was spent in a hospital.
Ohno explains, “Oral immunotherapy is not without risk. We closely monitored the children in the hospital, and four children had such severe reactions to the milk that we could not allow them to continue the treatment.”
After finishing 12 more months of treatment at home, the remaining 28 children stopped consuming milk for two weeks. Then, they underwent a double-masked, placebo-controlled food test to check if they could still handle milk without allergic reactions. They received minuscule amounts of milk or placebo in this test, beginning at 0.01 ml and rising every 20 minutes until they either reacted or reached 30 ml without a reaction.
The researchers looked at changes in the children’s immune system and gut bacteria during treatment and how these related to successful treatment. Success was defined as tolerating milk even after the treatment ended, as shown by passing the food test. They found that markers of milk allergy improved during treatment, and there were changes in gut bacteria. However, after avoiding milk for two weeks, only 7 out of 28 children passed the food test, even though they had previously been able to drink milk safely.
The team examined the clinical characteristics and gut flora types associated with effectiveness to determine why the medication was effective for some children. They discovered that kids with high milk-protein antibodies, eczema, or asthma were less likely to react to treatment.
Only kids who passed the final food test showed an increase in these bacteria during treatment. This is promising because while some factors like eczema or asthma are complex and can change, the bacteria in the gut can be influenced.
Hiroshi Ohno explains, “We found out how gut factors can help build tolerance to milk allergy through oral therapy. We need to understand how this works and find ways to improve oral therapy, maybe by adding probiotics.”
The presence of Bifidobacterium in gut bacteria is essential for overcoming milk allergy through oral immunotherapy. Further research is needed to understand the underlying mechanisms better and explore interventions targeting gut microbiota. These interventions can optimize the efficacy of treatment for milk allergy.
Journal reference:
- Ryohei Shibata, Naoka Itoh, et al., Gut microbiota and fecal metabolites in sustained unresponsiveness by oral immunotherapy in school-age children with cow’s milk allergy. Allergology International. DOI: 10.1016/j.alit.2023.10.001.