Relatively little is known about how people become allergic, but immunologist Franca Ronchese hopes exploring that can help prevent and treat allergies.
Prof Ronchese is head of the immune cell biology programme at the Malaghan Institute, and specialises in dendritric cells.
Franca Ronchese Photo: Supplied
Her research aims to find out what happens when we develop an allergy or allergic response: the cells that are involved, the chemicals they are producing, and what can be done to interrupt this process.
She says it's fairly well understood what happens in allergic reactions, but not much is known about the process of developing an allergy.
"In allergies ... our body is trying to fight infection and it's trying to fight something it thinks is dangerous and can affect our health.
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"For some reason, allergens - which are not dangerous, because pollens and so on do not really have an effect on our body - are mistaken for something that needs to be fought.
"I prefer to think of it as a mistaken identity - that our immune system not understanding what it's going to be exposed to."
She says dendritic cells appear to be the ones that start the immune response, to "detect and alert all the other cells in the immune system to respond to it".
What causes allergies?
Photo: 123RF
Prof Ronchese says people need to be exposed to allergens to develop an allergic reaction, but it's not clear exactly what is causing some people to develop that reaction while others do not.
There is some evidence the early stages of life are particularly important, however.
"There were some suggestions, some evidence, that whatever the mother does is already predisposing to some extent.
"People may have heard of this phenomenon called the allergic march, where children are born and they develop - very quickly - eczema.
"We know that this condition in very young babies is basically the initiation of a process where people are more likely to develop other kinds of allergies later in life."
Regardless of this there appears to be two main factors affecting whether people become allergic to something.
"The way we understand it is there is a sort of balance between our genes - those genes that make us more or less susceptible to being allergic - and the environment.
"Now we have learnt in the last five to 10 years is that actually all the bacteria that have lived with us for a very long time - in our gut, on our skin and so on - are also playing a very important role."
Peanut allergy affects between 1-3 percent of children in Western Europe, the US, and Australia. Photo: 123RF
Increases in allergies
Prof Ronchese says there has been an increase in allergies in Western countries.
"Probably what is going to be the culprit has been these rapid changes of lifestyle.
There's evidence having a pet or working with animals helps prevent allergies. Photo: 123RF
"People have moved from dirty communities in farms to much cleaner communities in cities, and their diet has changed, their lifestyle has changed, their food has changed.
"It has become more favourable for the development of allergies."
She says there is evidence from studies in Europe that growing up on a farm in close contact with animals can protect from certain allergies.
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Treatment: Desensitisation
Immunologists also know it's possible to curb or reduce allergic reactions over time, and this desensitisation has some proven success, Prof Ronchese says.
There are caveats, however.
"In a way it's a difficult therapy to give, these people can be highly allergic … the administrations are very controlled with very small amounts to start with. It can be dangerous, and they have to be repeated for a long time.
"My understanding - at this point it's not clear whether one cycle of desensitisation is sufficient or whether it needs to be repeated or maintained regularly with protocols that have not been developed yet."
"Whether we can cure them, time will tell. Maybe the desensitisation … will become more available, easier to access."
Treatment: Drugs
There are drugs coming onto the market that are getting better at treating allergic reactions, she says.
Photo: feverpitched/123RF
"They seem to work better than previous drugs, they seem to be more specific in the sense that some of the drugs that people with allergies take, like steroids, make you more susceptible to all sorts of infections.
"They [the new drugs] have not been available for that long that we can say what are the long term effects of being treated with those drugs."
Prevention beats a cure
Prof Ronchese says she hopes her research can lead to the kind of understanding of allergy that will allow us to prevent and avoid the things which cause allergic reactions in the first place.
She says simply turning off the response is a dangerous option.
"This is the typical double edged sword where if you completely wipe off this response you might make yourself more susceptible to things that in our clean world you don't come across very often but are still there."
To eat, or not to eat?
Prof Ronchese says it's possible the incomplete understanding of allergy development has contributed to the worsening rates.
"One of the pieces of advice that has gone out to mothers for example is to avoid food that can be potentially causing allergies during pregnancy, during breastfeeding, and not give them to their children when they are very young.
Advice to pregnant mothers to avoid allergens may not be helpful. Photo: 123RF
"Although in principle - yes, if you are allergic you should try to avoid allergens - there's no evidence that this prevents the development of allergies."
She says there is a way to predispose the body to accept allergens, we just don't know what it is.
"For example, food: we need to eat food, and especially in the old days there was little choice about food, there seems to be a predisposition to accept the food and not become allergic.
"Why this balance has altered so terribly in the last few years is something we need to understand."
Getting dirty or keep it clean?
She says there's some evidence detergents may also be part of the problem.
"So they remove the layer of protective lipids on our skin and make our skin more permeable ... The layer of greasy substance on our skin is actually protective and good to have."
But it's also tied into genetics.
Detergents and soaps likely have an effect on predisposition to allergy. Photo: 123RF
"There are some genetic predispositions to develop allergies and one of them that is very common in the Western population is a mutation in the protein that makes your skin tight and impermeable.
"Your skin becomes more likely to let substances through, to lose water, to become very dry and then whatever you are exposed to can access the deeper layers of your skin more easily.
"Detergent can do the same."
She says some studies show it's also helpful to have pets and other children around, however it's also important to keep in mind that not all dirt is helpful.
"Especially moulds are absolutely nasty, they have components that can really elicit a very strong reaction in our body.
While being exposed to some things can help prevent allergy, toxic moulds tend to be strictly harmful. Photo: 123RF
"They are absolutely something that should not be present in our homes at all. The human environment is rife with these kinds of fungi and we can see them in our test tubes … they elicit production of all sorts of proteins."
She says birth order has an effect as well.
"Firstborns are usually more likely to be allergic and as you have more children the rate of allergies tend to decline.
"If you want to have a child that's not allergic you should never have a first child, and that's going to be difficult, isn't it."