Hey fever! The surprise benefit of allergies

Long-suffering victims of allergies such as asthma and hay fever might enjoy a surprise benefit, according to research led by the University of New South Wales (UNSW).

In a paper to be presented at an international symposium in Sydney next week (Monday 28th July), the researchers show that people with one of these atopic diseases are up to 25 percent less likely to get the most common type of Non-Hodgkin Lymphoma (NHL).

The InterLymph Symposium is co-hosted by the Leukaemia Foundation, the Cancer Institute NSW, UNSW and the National Centre in HIV Epidemiology and Clinical Research.

The more atopic diseases the individual has, the less likely they are to succumb to NHL. If an individual has three of these conditions, they are 40 percent less likely to get NHL.

Having had asthma and hay fever for a long time also appears to be of greater benefit.

The result is significant given that the incidence of NHL in developed countries has escalated dramatically in the past 50 years. It is three times more prevalent now than it was in 1950, making it the sixth most common cause of cancer death in Australia, yet the cause of most cases remains unknown.

"This was a surprise result," said the lead author, Dr Claire Vajdic. "The only known strong risk factors for NHL are immune deficiency and certain infections. This occurs in people with uncontrolled HIV infection, and those who have had a solid organ transplant.

"So we thought other forms of immune dysregulation such as atopic diseases - including hayfever, asthma and food allergies - might relate to the development of lymphoma. It was therefore intuitive to think that these conditions would increase the risk, but in fact, they do the reverse," she said.

The research found that risk was reduced in B-cell NHL only. This is the most common type of NHL.

"While the relevant biological mechanisms are not yet known, the pooled data indicate that chronic and multiple atopic conditions impart the greatest reduction in risk," said Dr Vajdic. "Investigation of the genetic and environmental factors underlying atopy and the apparent inverse effect of atopy on NHL risk will inform our understanding of the complex biological pathways that may be involved."

The research involved a pooled analysis of data from 13 case-control studies involving 13,535 NHL cases and 16,388 control participants, funded by the Leukaemia Foundation.