Lau et al. (J Allergy Clin Immunol 2012;129:1040-1047) report their findings from a controlled trial of heat-inactivated bacterial lysate treatment in infants with inherited risk of atopy in this month’s issue. Citing proof-of-concept research and epidemiological reports on lowered atopy incidence in rural populations, the authors hypothesize that intentional exposure to heat-inactivated bacteria might confer protection from atopy. Their study included infants with one or both parents with a history of atopic disease (allergic rhinitis, eczema, asthma or combination).
Infants were treated orally with heat-killed Echerichia coli and Enterococcus faecalis lysate for 7 months, then followed until age 3 years. The primary outcome was the presence or absence of atopic dermatitis (AD) at the end of treatment. At 31 weeks, only 10% of treated infants with single parent risk developed AD compared to 19% of infants treated with placebo. The effect was even greater in infants with paternal atopy only. Treatment effect was strongest in infants with a single parent with allergic rhinitis. No effect was observed for infants with allergic asthma, AD, or combination.
Though Lau et al. measured gut flora during the treatment period, there was no measurable alteration in flora that could be attributed to treatment. Additionally, total serum IgE levels did not differ between the two groups. The authors conclude that their study shows a possible differential atopy risk associated with paternal heredity.
The authors point out that maternal atopy seems to carry a higher risk of infants developing eczema. Why then in this study are infants of untreated atopic dads & nonatopic moms apparently more likely (32% risk) to develop eczema than the group of children who had either an atopic mom or dad but not both (19% risk)? Is this an effect of the sample size, or am I reading the paper wrong?
ReplyDeleteThank you for your questions. We forwarded them to Dr. Susanne Lau, lead author on this paper. She responds, "It is well known from the Literature that infants with double heredity for atopy (both parents atopic) are more likely to develop eczema than [infants] with only One atopic parent. The Intervention worked better in children with atopic fathers compared to the group with atopic mothers. Maternal atopy can have a stronger impact on the infant than paternal because the in utero environment plays a major role in priming the immune system... [In this study it] is true that the AD prevalence is higher in the group of children with atopic fathers compared to those children with atopic mothers, especially in the placebo group (9.4 versus 31.7% AD prevalence at age 7 months)."
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