Probiotics may protect against allergy in newborns
Supplementation with the probiotic Escherichia coli (E. coli) strains O83:K24:H31 in newborns resulted in effective intestinal colonization, which was associated with a decreased incidence of allergy over a 5-year follow-up period, according to a study presented at the recent International Congress of Immunology meeting (ICI 2016) in Melbourne, Australia.
“The replacement of natural, incidental, and at times pathogenic colonization of the intestine by controlled oral administration of E. coli after birth may be a therapeutic option to reduce and possibly prevent allergies later in life,” said the researchers.
The open, randomized controlled trial included 158 full-term infants born vaginally who were breastfed and grouped into: group AC, colonized infants of allergic mothers; group A, noncolonized infants of allergic mothers; and group H, control infants of healthy mothers. [Int Arch Allergy Immunol 2010; 153:201-206]
Infants in group AC received an oral dose of lyophilised E. coli (O83:K24:H31; 0.8x109 in 1 mL) vaccine within 48 hours after birth, followed by a 3-time weekly dose for a period of 4 weeks. All the participants were followed-up with sampling of maternal blood, infant blood, and infant stool before vaccination, at 3 days of life, 3 and 6 months, and 1, 2, 3, and 5 years.
There was no sign of E. coli O83:K24:H31 in the infant stool samples before vaccination, while 71 percent of the infants in group AC showed evidence of E. coli O83:K24:H31 or O83 colonization in their stools starting from 3 days of life, with 26 percent having colonization that lasted for 5 years during the follow-up period.
At 5 years, colonized infants in group AC had a significantly reduced incidence of allergy compared with unvaccinated infants in group A (4 percent vs 31 percent; p<0.001).
“It is evident that colonization with probiotic E. coli suppresses development of allergy,” said the researchers.
Also, allergic mothers had significantly higher serum interleukin-5 (IL-5) levels (p=0.0071) and slightly higher IL-4 levels than healthy mothers.
Additionally, nonvaccinated infants of allergic mothers (group A) had higher levels of IL-4 and IL-13, while infants of healthy mothers (group H) had higher levels of interferon gamma (IFN-ƴ) and transforming growth factor beta (TGF-β) at 3 months in comparison with each other.
Nonetheless, colonization with E. coli did not significantly change the serum and stool levels of cytokines in group AC infants.
The researchers said comparing cytokine levels was a challenge due to a large number of samples being under the detection limit and the huge variability between samples.
“Cytokine levels do not reflect the pronounced clinical effect of colonization with probiotic E. coli used in our trial,” they added.