A genetic² breakthrough raises hope of easing suffering for people with chronic³ lung disease - and maybe those just fighting a common cold.

一项基因研究突破激起了慢性肺病患者减少痛苦的希望，甚至对普通感冒可能也会有所帮助。

Cystic fibrosis can be deadly

The biological reason why the lungs of people with conditions such as asthma⁴ and cystic fibrosis（囊肿型纤维化） often clog⁵（阻塞） up with thick mucus（黏液） has been unclear.

But Cincinnati Children's Hospital researchers have identified the main genetic switch behind the build-up.

The Journal of Clinical Investigation⁶ study raises hopes of new treatments.

Lead researcher Dr Jeffrey Whitsett said a way to combat excessive mucus production would potentially be a significant step forward, as there was currently no effective treatment to remove build-up once it had taken place.

It was thought that after airways⁷ were attacked by an allergic⁸（过敏的） response or inflammation（发炎，红肿） mucus cells, known as goblet⁹ cells（杯状细胞）, divided and proliferated¹⁰（增殖） at a very fast rate - a process known as hyperplasia（增生，数量性肥大）.

But instead the Cincinnati team discovered that a type of lung cell, called Clara cells, instead morph（变种，变体） into goblet cells - a process called metaplasia（转化，组织变形）.

They also showed that the process was reversible - goblet cells can change back to Clara cells if the initial problem is dealt with.

In work on mice, the researchers also identified a gene¹ called SPDEF as key to the process of mucus production.

Allergic reaction

They used a protein from egg whites to induce（劝诱，说服） an allergic reaction in inflammation in the animals' lungs, and showed that SPDEF activity soared（飞舞，高耸） in the affected¹¹ tissues, leading to hyper-production of mucus.

However, when the gene was switched off inflammation and excessive mucus production did not occur.

And mice lacking SPDEF were unable to increase mucus production or develop goblet cells.

Further analysis showed that SPDEF plays a complex role switching other genes¹² involved in inflammation and mucus production on and off.

The researchers hope it will be possible to develop treatments that influence activity of the gene, but warn tests in humans are still several years away.

Dr Keith Prowse, spokesperson for the British Lung Foundation, said: "Excess mucus production blights¹³（枯萎病） the lives of millions of patients with chronic lung conditions such as cystic fibrosis and chronic（长期的，慢性的） obstructive（妨害的，阻碍的） pulmonary disease（肺病）.

"At present there are only a few treatments available and they are often not very effective.

"The finding that SPDEF which controls mucus production could lead to new and effective treatments which would benefit the millions of people with chronic lung disease in the UK."

Dr David Halpin is a spokesman for the British Thoracic Society and a consultant¹⁴ respiratory（呼吸的） physician at the Royal Devon and Exeter Hospital.

He said: "Sputum production is a symptom of respiratory disease which is poorly treated by current medicine.

"Any advance in the understanding of the mechanisms¹⁵ responsible for this is likely to be a benefit to patients."