Scientists discover genetic disease which causes recurrent respiratory infections

(Press-News.org) Cambridge scientists have discovered a rare genetic disease which predisposes patients to severe respiratory infections and lung damage. Because the scientists also identified how the genetic mutation affects the immune system, they are hopeful that new drugs that are currently undergoing clinical trials to treat leukaemia may also be effective in helping individuals with this debilitating disease.

For the study, led by the University of Cambridge in collaboration with the Babraham Institute and the MRC Laboratory for Molecular Biology, the researchers first examined genetic information from individuals who suffer from immunodeficiency and are predisposed to infections. From this group, the scientists identified a unique genetic mutation in 17 patients that suffer from severe respiratory infections and rapidly develop lung damage.

The researchers, who were primarily funded by the Wellcome Trust, MRC, BBSRC and the National Institute for Health Research (NIHR) Cambridge Biomedical Research Centre, found that the mutation increases activity of an enzyme called Phosphoinositide 3-Kinase δ (PI3Kδ). The enzyme is present in immune cells and regulates their function. However, constantly activated PI3Kδ impairs work of these immune cells, preventing them from responding efficiently to infection and providing long-lasting protection. Consequently, patients with this mutation have severe and recurrent infections.

"Patients with this mutation have a defect in the immune cells, so their protection from infections is weak and inefficient," said Sergey Nejentsev, Wellcome Trust Senior Research Fellow from the University of Cambridge who led the research. "We called this newly identified disease Activated PI3K- δ Syndrome (APDS) after the enzyme in the immune system that is affected by the genetic mutation."

The researchers believe that it may be possible to treat APDS in future. There are currently drugs in clinical trials for leukaemia that were designed specifically to inhibit the PI3Kδ enzyme. The researchers have already shown that these drugs reduce activity of the mutant protein.

Alison Condliffe, joint senior author on the paper from the University of Cambridge, said: "We are very excited by the prospect of using these drugs to help patients with APDS. We believe that they may be able to restore functions of immune cells, thereby reducing infections and preventing lung damage."

Although the prevalence of the disease is not yet known, the scientists believe that it is relatively frequent compared to other immunodeficiencies and may underpin immunodeficiencies and chronic lung disorders in a substantial fraction of patients.

"It is very important that doctors consider a possibility of APDS in their patients," said Dr Nejentsev. "A simple genetic test can tell if the patient has the mutation or not. We believe that now many more APDS patients will be identified all over the world."

### For additional information please contact: Genevieve Maul, Office of Communications, University of Cambridge
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Notes to editors:

1. The paper 'Phosphoinositide 3-Kinase δ Gene Mutation Predisposes to Respiratory Infection and Airway Damage' will be published online by Science Express on 18th October

2. The Babraham Institute, which receives strategic funding (a total of £23.1M in 2012-13) from the Biotechnology and Biological Sciences Research Council (BBSRC), undertakes international quality life sciences research to generate new knowledge of biological mechanisms underpinning ageing, development and the maintenance of health. The Institute's research provides greater understanding of the biological events that underlie the normal functions of cells and the implication of failure or abnormalities in these processes. Research focuses on signalling and genome regulation, particularly the interplay between the two and how epigenetic signals can influence important physiological adaptations during the lifespan of an organism. By determining how the body reacts to dietary and environmental stimuli and manages microbial and viral interactions, we aim to improve wellbeing and healthier ageing.

3. Over the past century, the Medical Research Council has been at the forefront of scientific discovery to improve human health. Founded in 1913 to tackle tuberculosis, the MRC now invests taxpayers' money in some of the best medical research in the world across every area of health. Twenty-nine MRC-funded researchers have won Nobel prizes in a wide range of disciplines, and MRC scientists have been behind such diverse discoveries as vitamins, the structure of DNA and the link between smoking and cancer, as well as achievements such as pioneering the use of randomised controlled trials, the invention of MRI scanning, and the development of a group of antibodies used in the making of some of the most successful drugs ever developed. Today, MRC-funded scientists tackle some of the greatest health problems facing humanity in the 21st century, from the rising tide of chronic diseases associated with ageing to the threats posed by rapidly mutating micro-organisms. http://www.mrc.ac.uk. The MRC Centenary Timeline chronicles 100 years of life-changing discoveries and shows how our research has had a lasting influence on healthcare and wellbeing in the UK and globally, right up to the present day. http://www.centenary.mrc.ac.uk

4. The Wellcome Trust is a global charitable foundation dedicated to achieving extraordinary improvements in human and animal health. It supports the brightest minds in biomedical research and the medical humanities. The Trust's breadth of support includes public engagement, education and the application of research to improve health. It is independent of both political and commercial interests. http://www.wellcome.ac.uk

5. The National Institute for Health Research (NIHR) is funded by the Department of Health to improve the health and wealth of the nation through research. Since its establishment in April 2006, the NIHR has transformed research in the NHS. It has increased the volume of applied health research for the benefit of patients and the public, driven faster translation of basic science discoveries into tangible benefits for patients and the economy, and developed and supported the people who conduct and contribute to applied health research. The NIHR plays a key role in the Government's strategy for economic growth, attracting investment by the life-sciences industries through its world-class infrastructure for health research. Together, the NIHR people, programmes, centres of excellence and systems represent the most integrated health research system in the world. For further information, visit the NIHR website.

6. The National Institute for Health Research (NIHR) Cambridge Biomedical Research Centre is a partnership between the University of Cambridge and Cambridge University Hospitals Foundation Trust. They receive substantial levels of funding from the NIHR to translate fundamental biomedical research into clinical research that benefits patients and improves healthcare provision.