Immunology

The Leipzig Helmholtz Center for Environmental Research has gained new insights on the influence of tobacco smoke in utero. For the first time, it could be demonstrated with smoking pregnant women and their children, how exposure to tobacco smoke affects the development of human immune system on molecular level.  The focus thereby was on microRNA - a short, single-stranded RNA molecule that is now recognised as playing an important role in gene regulation. 

For some time now, the impact of environmental stressors during pregnancy on allergy risk among new-born children is a main research topic at Leipzig Helmholtz Center for Environmental Research (UFZ). As part of the long-term study LINA, environmental immunologists from Leipzig have been focussing on tobacco smoke as an environmental stressor. The main objective for Dr Gunda Herberth was to reveal the influence of tobacco smoke on the development of children's immune systems - at molecular level.  From the results that were recently published in the "Journal of Allergy and Clinical Immunology", one thing is certain: "For the first time we were able to describe the effect of prenatal environmental stressors on the regulation of microRNA." 

Former studies have already proven that smoking during pregnancy can harm the unborn child: Newborns from smoking mothers have shown low birth weights and impaired lung functions; later on in life respiratory diseases, diabetes type II, asthma or cardiovascular diseases were also more common. However, the exact molecular mechanisms and processes that are behind such developments still struggle researchers. 

For this reason, Dr. Gunda Herberth and Dr. Irina Lehmann from the UFZ decided to address the relatively recent research area of microRNA. From the early 1990´s these cell components started to become more and more of a focus in molecular and cell biology. In the meantime, for humans more than 1,200 different short, single-stranded RNA molecules have been named, some of them playing an important role in immune response.  Among others, they have a considerable influence on the differentiation of regulatory T cells (Treg cells), which in turn prevent an overactive immune system and thus autoimmune diseases.  If there are insufficient Treg cells or if their function is impaired, the self-regulatory function of the immune system will be reduced, possibly resulting in allergies.    

To investigate the relationship between smoking mothers during pregnancy on the one hand and their children´s risk of developing allergies on the other, the scientists from Leipzig examined microRNA-223, microRNA-155 and regulatory T cells - not only in the blood samples of pregnant women (36 weeks pregnant) but also at birth in the cord blood of their babies. At the same time, questionnaires were filled out and urine samples of the pregnant women were tested to substantiate the effect from exposure to tobacco smoke and/or from volatile organic compounds resulting from smoking. From the pool of mothers participating in the LINA-study, 315 mothers (6.6 percent of whom were smokers) and 441 children were consulted in these investigations.