Worm and stomach bacteria: our allies in the battle against allergic asthma

Parasitic worms and stomach bacteria suppress immune reactions such as allergic responses. Parasitologist Hermelijn Smits and lung specialist Christian Taube from the LUMC are trying to learn from these micro-organisms.

Parasitic worms and stomach bacteria protect themselves by suppressing the immune system, but this also supresses other immune responses, such as allergic reactions. Parasitologist Hermelijn Smits and lung specialist Christian Taube from the LUMC are trying to learn from these micro-organisms, so that they can develop new drugs against allergic asthma.

Parasitologists from the LUMC discovered that inflammatory disorders such as asthma and allergies are much less prevalent in developing countries, where people more frequently suffer from worm infections. ‘Research on test animals showed that these factors are inter-dependent. Parasitic worm infections seem to protect people against asthma and allergies,’ Hermelijn Smits explains. A similar discovery was made for the stomach bacterium helicobacter pylori. Here, too, there is a connection between the fact that this stomach bacterium no longer occurs in the Western world and the sharp increase in the number of people with allergic asthma. Professor of Pulmonary Diseases Christian Taube explains: ‘Epidemiological studies have shown that asthma occurs much less frequently in people who have previously had the helicobacter pylori infection. We studied this phenomenon further and saw that these bacteria do indeed lower the chance of developing asthma.’ 

Tolerance

How is it that these micro-organisms have such a protective effect against allergic asthma? It has to do with their interaction with the immune system. Both organisms are able to suppress the immune system, in order to protect themselves. In doing so, they also suppress other immune system responses, including those against allergens. Smits and Taube want to find out how these micro-organisms do this. It looks as though the dendritic cells in particular play an important role in this process. They are the gatekeepers of the human body, and are found in the lungs, for example, where they recognise invading pathogens and allergens, and then decide whether they should either activate or suppress an immune reaction. ‘We are aware that the presence of helicobacter pylori leads to more suppressive dendritic cells, and therefore to a higher degree of tolerance,’ Taube explains. 

Asthma vaccine

In a joint research project between the Netherlands Lung Foundation and the LUMC, Smits and Taube are now isolating all kinds of molecules that are excreted by the parasitic worms and the stomach bacteria, in order to test their effect on the dendritic cells. The two researchers now have several potential candidate molecules in mind. Ultimately they hope to be able to use these substances to treat asthma. Patients will then be able to benefit from the advantages of these micro-organisms, without suffering the negative aspects of an infection with a stomach bacterium or parasitic worm. It may be possible that the substances themselves could serve as a kind of vaccine for young children who are susceptible to this disease.