We thank Kountouras and colleagues for their interest in our work and their comments on our article (1). Kountouras et al. argue that a low infection rate with H. pylori and a high prevalence of asthma do not have to be associated, as there are certain areas with low asthma incidence despite low H. pylori infection rates. Indeed, asthma is a multifactorial disease that can be influenced by many factors such as genetics, diet, and exposure to environmental factors like pollution and microbial compounds. Therefore, it could be speculated that depending on the surrounding environment, different factors might be predominant. Some epidemiological data have suggested that infection with H. pylori might play a role in determining asthma susceptibility (2, 3). In addition, several experimental studies have investigated the underlying molecular mechanism (4, 5). However, these findings do not show that infection with H. pylori is the only factor influencing the development of asthma, and it is completely plausible that in different surroundings, other factors might be predominant in determining asthma susceptibility.
Kountouras et al. also argue that infection with H. pylori is associated with a higher risk of adult-onset asthma, and that European children infected with a CagA-negative strain are more likely to develop asthma. Indeed, it has been shown that the protective effect of experimental infection against development of allergic airway inflammation is more effective in neonatal mice than in adult mice (4). In addition, CagA-deficient H. pylori strains could still inhibit allergic airway inflammation in murine models (4). However, the focus of the present paper was on the use of bacterial lysates as a novel treatment option for allergic airway disease.
We agree completely that negative effects on health (ulcers, cancer, and other diseases) of an infection with H. pylori need to be considered, and we postulate clearly that eradication therapy should be considered in patients infected with H. pylori. Our study does show that in addition to experimental infection, administration of bacterial lysates can also ameliorate allergic airway disease, which potentially avoids all the drawbacks of live infection. Preliminary data show that the extract can also induce tolerance on cultured human cells (Y. van Wijck, unpublished observations), and some bacterial compounds have been identified already that might be candidate molecules and need to be further evaluated. This could lead to novel approaches for treatment of asthma.
- Copyright © 2018 by The American Association of Immunologists, Inc.
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