A promising probiotic for non-IgE-mediated cow’s milk protein allergy
As a new therapeutic approach for this disease in infants, researchers have proposed to supplement hypoallergenic formulae with lactobacillus to correct the gut dysbiosis associated with the allergic process.
Cow’s milk protein allergy (CMPA), the most common childhood food allergy, is IgE-mediated in approximately 50 to 65% of cases. In IgE-mediated allergies, symptoms appear within hours of ingestion. Other reactions are referred to as “non-IgE-mediated”. Extensively-hydrolyzed formulae (EHF), which contain smaller peptides and no lactose, are prescribed to allergic babies. An Italian team that had already demonstrated the therapeutic potential of supplementing EHF with Lactobacillus rhamnosus GG (LGG) in IgE-mediated allergies also studied non-IgE-mediated allergies.
One phylum enriched in allergic subjects
Researchers built a cohort of 46 allergic infants and 23 healthy infants. Allergic infants, who were aged between 1 and 26 months, were further divided into three groups and monitored for 6 months: a group with no therapeutic intervention, a group receiving EHF alone and a group receiving EHF + LGG. First finding from the stool sample analysis: Bacteroides and Alistipes (two bacterial genera belonging to a phylum associated with increased gut permeability), among others, were more abundant in the intestines of allergic infants than in control subjects.
Restorative effects of LGG
Most importantly, the benefits of supplementing EHF with LGG were confirmed. Dysbiosis was best corrected in the EHF+LGG group: the gut microbiota composition and structure of infants in this group became similar to those of healthy controls, with a decrease in the relative abundance of Bacteroides and Alistipes, while the proportion of Lactobacilli increased. Initially low compared to non-allergic infants, fecal butyrate levels were also increased in the presence of LGG, as these bacteria produce butyrate. These short-chain fatty acids could positively modulate immune tolerance mechanisms.
Dysbiosis and types of CMPA
By combining the data from this study with their previous findings, the researchers were able to demonstrate that dysbiosis was more pronounced in IgE-mediated CMPA than in non-IgE-mediated allergies. The authors noted, however, that the age difference between the treatment group and the control group may have influenced the composition of their respective gut microbiotas. Age can indeed have a significant impact during the first year of life as the microbiota undergoes substantial changes during this period. Further research will therefore be needed to confirm the therapeutic potential of LGG-enriched formulas in curbing the ever-increasing prevalence of atopic diseases*.
* CMPA in the first year of life typically indicates an atopic predisposition which may expose those infants to an increased risk of developing immune disorders in their later life
Canani RB et al. Gut microbiota composition and butyrate production in children affected by non-IgE-mediated cow’s milk allergy. Scientific Reports, volume 8, Article number: 12500 (2018)