Chemical genetic modification behind pollen allergy

The dramatic increase in allergies, diseases of the joints, diabetes and other common illnesses that affect the immune system suggests that environmental factors are very significant. A study of people with pollen hay fever now shows that this may be the result of chemical changes in the genes, called DNA methylation.

Environmental impact is difficult to study in most illnesses, however, as such factors are often unknown and because there are such great differences between patients who seem to have the same illness.

In an international study led from Linköping University, researchers chose to study pollen hay fever as a model illness. Both the external factor (pollen) and the most important cell (T lymphocytes) are well known. T-cells can be separated from blood from patients and healthy subjects and stimulated by pollen in test-tubes.

Environmental factors can be significant

The study, published in the journal PLoS Genetics showed that DNA methylation of T-lymphocytes completely separated out patients from healthy control subjects. In addition, there was a strong connection with how sick the patients were. The findings show that environmental factors can be very significant in inflammation diseases, due to their impact on DNA methylation. Increased methylation leads to reduced activity and vice-versa.

These new findings may be significant for both diagnosis and therapy. For example, it is already known that patients with pollen hay fever can be cured using immunotherapy, where patients are treated with small amounts of pollen over a longer period. Researchers are now investigating whether this influences DNA methylation.

The study is based on an EU project led by the Centre for Individualized Medication (CIMed) at LiU and a new branch of research, systems medicine, which aims to understand how a change in the interaction between a large number of genes and environmental factors leads to illness.

Article: DNA Methylation Changes Separate Allergic Patients from Healthy Controls and May Reflect Altered CD4+ T-Cell Population Structure by C E Nestor, F Barrenäs, H Wang, A Lentini, H Zhang, S Bruhn, R Jörnsten, M A Langston, G Rogers, M Gustafsson and M Benson. PLoS Genetics 10(1) 2014.