World allergy week (22-28 april): scientists discover gene that can reduce sensitivity to allergies
Among the hot topics raised at the recently held World Allergy Congress (WAC) in Orlando, Florida (USA) – ahead of World Allergy Week (22-28 April) – was the discovery of a gene which can switch on or turn off people’s reaction to allergies.
Scientists from the University of Queensland (Australia) were able to manipulate the immune response which triggers allergy symptoms in mice. An allergic response is typically caused by immune cells, commonly referred to as T-cells, reacting to a protein in an allergen. The challenge lies in the fact that T-cells can become resistant to treatments over time.
Dr Jonny Peter, Allergy Advisor to Pharma Dynamics – one of the leading providers of allergy medication in the country – explains that the researchers essentially found a way to erase the immune memory of these T-cells in mice with a form of gene therapy, thus allowing the immune system to accept the protein as opposed to viewing it as a threat.
“If the same is achieved in human cells, researchers claim that it could lead to gene therapies that provide life-long protection from severe allergies to peanuts, shellfish, other food and even asthma with a single treatment. However, sceptics have cautioned against this claim, since asthma is caused by a completely different mechanism than the one behind food allergies, but most agree that the research holds exciting possibilities in store. Human trials are expected to start in about five to six years, but only time will tell whether it is a viable option,” he says.
To build on the evidence which supports gene-based approaches in tackling allergic disease, other experts presented research related to the mechanisms used to pinpoint the various genetic components that can cause allergies.
Dr Peter says up to now progress on this front has been stifled by the lack of high throughput technologies to investigate genetic variation in a large enough sample of patients. The development of Genome-Wide Association Studies (GWAS), however, allows researchers to investigate large numbers of common variants spanning the entire genome in allergic- and non-allergic patients.This revolutionised scientists’ understanding of the genes responsible for a range of allergic diseases, including those for allergic rhinitis, asthma and atopic dermatitis.
“In the future, we can expect scientists to continue to use GWAS to identify novel genes for allergic diseases, while integrating analyses of rare variants via epigenetic mechanisms (cell division) and expression quantitative trait loci (eQTL). eQTL is a method used to explain a fraction of the genetic variance of a gene expression phenotype, which will help scientists gain a better understanding of why allergies develop in the first place and how they could be prevented or treated.”
In South Africa alone, an estimated 30% of the population suffer from allergic rhinitis (inflammation in the nose, which occurs when the immune system overreacts to allergens in the air), while 40% suffers from asthma.
On another front, the effect of climate change on pollen allergy and respiratory allergic diseases was also at the forefront of the debate. Although scientists are sketchy on exactly how climate change will impact respiratory allergies, they say the extreme weather events of the past decade have resulted in massive changes in our climate to which biologic systems on all continents are reacting – something thatdoctors and allergy-sufferers should keep a close eye on.
Dr Peter cites an international study that was done on the management of allergic rhinitis, which involved both doctors and patients, where 51% of patients blamed pollution for their worsening symptoms, while 80% incriminated climate change.
“There is some evidence of significantly stronger allergenicity in pollen from trees growing at increased temperatures and that climate change may affect air pollutant levels such as tropospheric ozone (O3), but a lot more research is needed before firm conclusions can be made.”
Another recent survey conducted among 1 184 doctors who belong to the American Academy of Allergy Asthma and Immunology (AAAAI) confirmed that most doctors are witnessing medical problems caused by climate change among their patients. Nearly two-thirds reported a need for increased care for allergic sensitisation and symptoms following exposure to plants or mould.
Possible effects of climate change on respiratory allergy could be as follows:
- An increase in rain and heavy downpours, such as thunderstorms could lead to asthma epidemics.
- Global warming could increase the length and intensity of the pollen season causing prolonged respiratory allergy symptoms.
- On the flipside, a reduction in colder days could potentially lower a patient’s risk to upper respiratory infections.
- Changes in atmospheric circulation patterns may increase the occurrence of long distance transport of pollen and pollutants.
- Increased air pollution and risk of wildfire smoke (CO2) could lead to a worsening of respiratory allergies.
“The rate at which allergic diseases and asthma are increasing worldwide, is alarming. The World Allergy Organisation (WAO) reports that worldwide sensitisation to allergies in the environment is present in up to 40% of the population. These disorders significantly impair a patient’s quality of life. Apart from chronic sneezing, nasal stuffiness and a post-nasal drip making them more susceptible to colds and flu, sufferers also complain of fatigue, memory loss, weakened physical and social functional and depression, hence the intense focus on developing safe and effective therapies for the future.”
“World Allergy Week not only allows us to raise local awareness of allergic diseases, but to also share new insights into preventing and managing allergic conditions. For now, there is no silver bullet that can treat each and every symptom, but antihistamines, decongestants and other treatments should offer relief. Thankfully international research shows a promising future for treating and possibly even preventing (certain) allergies all-together,” says Dr Peters.
For more info regarding allergies or daily pollen counts, visit www.allergyexpert.co.za.