Kate Johnson

November 11, 2013

BALTIMORE — Women who receive immunotherapy injections before pregnancy might be protecting their offspring from allergies, according to a pilot study.

"The hope is that it could be an added benefit of allergy shots," senior investigator Jay Lieberman, MD, from Le Bonheur Children's Hospital and the University of Tennessee Health Sciences Center in Memphis. Although the findings show only a trend toward this effect, the benefit is clinically relevant, he told Medscape Medical News.

"There is now evidence of epigenetic modifications with allergy shots," said Dr. Lieberman. "It changes histone modification or methylation of genes that express tolerogenic cytokines. It's debatable whether those modifications are inheritable or not," but the data warrant further study.

The investigators surveyed women 14 to 48 years of age who had physician-diagnosed allergic rhinitis and were attending an outpatient allergy clinic.

Brandon Todd, a fourth-year medical student at the University of Tennessee Health Sciences Center and one of the study investigators, presented the results here at the American College of Allergy, Asthma & Immunology (ACAAI) 2013 Annual Scientific Meeting.

 
It appears that if mothers got the shots any time before their child's birth, the child had some protection.
 

Of the 800 mailed surveys, 192 were completed, and 148 of those came from women who had given birth to a total of 277 children, Todd reported. The median age of the children was 11 years, and 54% were male.

Mothers were asked whether they had received immunotherapy for allergic rhinitis and if so, when. They were also asked about any allergic disease in their children, such as asthma, eczema, food allergy, or allergic rhinitis.

Allergic disease in children was more common when mothers had not received immunotherapy than when they did (62% vs 54%), but the difference was not significant (P = .3604).

There was a trend toward rates of allergy being higher in children who were breast-fed than in those who were not (58% vs 66%; P = .1510), in first-born than in later-born children (64% vs 56%; P = .2180), and in children with fathers who had allergies or asthma than in those whose fathers did not (65% vs 58%, P = 0.2979). These associations have all been previously reported.

On multivariate analysis, after controlling for these variables, the risk for allergy was marginally lower in children whose mothers had received immunotherapy either before or during pregnancy than in children whose mothers had not (odds ratio, 0.83 vs 0.84).

"It appears that if mothers got the shots any time before their child's birth, the child had some protection," explained Dr. Lieberman. He noted that "if you finish 3 years of shots, the protection lasts for years."

Some of the first human evidence suggesting an epigenetic effect of allergy immunotherapy was published last year by a team from Stanford University in California (J Allergy Clin Immunol. 2012;130:215-24.e7).

Kari Nadeau, MD, the senior author of that study, told Medscape Medical News that "the in utero effects of immunotherapy could have a beneficial effect in the developing fetus, decreasing the likelihood of severe atopy."

She said the study by Dr. Lieberman's team is the first that she is aware of to explore whether those epigenetic changes are inherited by the next generation. "It is hopeful," she said, "although blood samples would have enabled actual epigenetic investigation."

She added that the findings, although very preliminary, "speak to changes that might be happening in the germ-line cells before conception, but this would need further study. The statistics are not strong, but it is an interesting trend that definitely sets the stage for further large studies."

Jay Portnoy, MD, chair of the ACAAI abstract committee, said the findings offer practical information for women and their doctors.

"Many women and obstetricians think allergy shots during pregnancy are contraindicated, but standard practice among allergists is that if a woman is getting allergy shots while she becomes pregnant, it does not hurt the fetus, it is not teratogenic, to stay on a maintenance dose," he told Medscape Medical News. However, "we don't recommend starting or increasing the dose during pregnancy, because there's a slightly higher risk of anaphylaxis during the build-up phase," he added.

Dr. Portnoy suggested that women with allergies who are thinking about getting pregnant might consider starting immunotherapy before they conceive.

The authors and Dr. Nadeau have disclosed no relevant financial relationships. Dr. Portnoy reports financial relationships with Sanofi, Thermo Fisher Scientific, and Mylan.

American College of Allergy, Asthma & Immunology (ACAAI) 2013 Annual Scientific Meeting: Abstract 24. Presented November 10, 2013.

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