Research sheds light on a novel disease mechanism in chronic smokers

May 21, 2018, Biochemical Society

Research published in the journal Clinical Science suggests that an immune signalling protein called interleukin (IL)-26 is increased among chronic smokers with lung disease and this involvement reveals disease mechanisms of interest for developing more effective therapy for these hard-to-treat patients.

Chronic tobacco smokers have a substantially increased rate of chronic obstructive pulmonary (COPD), and bacterial infections and these disorders respond poorly to currently available therapies. This is thought to be associated with the accumulation of a type of white blood cell, called neutrophils, in their airways.

Dr. Karlhans Fru Che and Professor Anders Lindén at Karolinska Institutet, Stockholm, led a team of researchers from universities in Sweden and Finland to investigate why chronic smokers with lung disease have such high levels of neutrophils. They found that an immune signalling protein called IL-26 is present at high levels in the lungs of these patients. This IL-26 is thought to be a pro-inflammatory 'neutrophil mobilizer' and has previously been found at high concentrations in patients with autoimmune conditions such as Crohn's disease and rheumatoid arthritis, as well as chronic infections such as hepatitis C, all of which are also associated with excessive accumulation of neutrophils.

"Previous research shows that the immunological alterations in the airways of chronic smokers, with or without COPD and chronic bronchitis, include an excessive accumulation of neutrophils in parallel with an enhanced frequency of bacterial infections. Our findings show for the first time that IL-26 may be involved in the mobilization of neutrophils and in the response to bacterial colonization in chronic smokers with or without COPD" commented the lead author on the study, Dr. Karlhans Fru Che from Karolinska Institutet, Sweden.

Dr. Che and his colleagues looked at the effects of water-soluble tobacco smoke components on human lung cells and found that the exposure triggered the cells to start producing higher than normal amounts of IL-26. They also found increased amounts of other pro-inflammatory proteins in the tobacco-exposed cells such as NF-κB, which appeared to increase in response to increased IL-26 concentrations. Abnormal regulation of NF-κB has been linked to autoimmune disease, infections and cancer in other research.

While the researchers found that IL-26 levels were higher than normal in the chronic smokers, regardless of whether they had clinically stable COPD, they also found that those who did have chronic bronchitis or growth of bacteria had higher levels of IL-26 than those who did not. Moreover, the chronic smokers with exacerbations of COPD had higher levels of IL-26 than those with clinically stable COPD.

"In a previous study, we showed that IL-26 is released by a bacterial compound in healthy human airways and that it enhances the chemotactic response of neutrophils. By now showing that IL-26 is involved in the excessive mobilization of neutrophils in chronic smokers with or without COPD and chronic bronchitis, we strengthen the evidence that this cytokine bears potential as a target for monitoring of and therapeutic intervention in disorders characterized by neutrophilic inflammation. However, more studies are needed to improve the understanding of the more precise mechanisms of action of IL-26 before this cytokine can be targeted in clinical trials" explained Dr. Che.

The researchers believe their work indicates that IL-26 is a promising target to monitor risk or burden in chronic smokers and that this knowledge could help develop more effective therapies for this difficult-to-treat group in the future. However, they acknowledge that further work is needed to confirm this.

"Our findings position IL-26 as a promising molecular target that may help improve our understanding of the pathogenic mechanisms behind pulmonary morbidities in chronic tobacco smokers. This knowledge may prove useful for developing new diagnostic tools and criteria as well as for monitoring of disease over time. In a longer perspective, this knowledge may even prove useful for developing new therapy against tobacco-related lung diseases such as COPD, chronic bronchitis and, perhaps, against repeated bacterial infections in the airways." commented Dr. Che.

Professor Ilja Striz, Associate Editor of Clinical Science commented "The pathogenesis of chronic (COPD) in chronic tobacco smokers is associated with an excessive accumulation of in the airways. Results of this collaborative study of authors from Sweden and Finland show that interleukin-26 (IL-26), a neutrophil-mobilizing cytokine, is increased in the airways of chronic with or without COPD. Upregulation of IL-26 in the airways in response to tobacco smoke represents a novel mechanism by which neutrophil recruitment to the lung is regulated and emerges as a new promising molecular target."

Explore further: Downregulation of miR-126 augments DNA damage response

More information: Karlhans Fru Che et al, The neutrophil-mobilizing cytokine interleukin-26 in the airways of long-term tobacco smokers, Clinical Science (2018). DOI: 10.1042/CS20180057

Related Stories

Downregulation of miR-126 augments DNA damage response

August 2, 2017
(HealthDay)—For cigarette smokers and patients with chronic obstructive pulmonary disease (COPD), downregulation of microRNA-126 (miR-126) augments DNA damage response (DDR), according to a letter to the editor published ...

Quit-smoking drug safe for lung disease patients

May 10, 2017
Medication that helps smokers to quit is safe for use by people with chronic lung conditions, research suggests.

Loss of airway blood vessels is associated with risk of death in smokers without COPD

May 23, 2017
In a new study, CT-measured vascular pruning - the diminution of distal pulmonary blood vessels (vessels on the outer edges of the lungs) - was associated with increased risk of death in smokers without chronic obstructive ...

Defect in zinc supply mechanism affects pathology of intractable pulmonary diseases

December 29, 2017
Obstructive pulmonary disease is a collective term for refractory respiratory diseases with chronic airway inflammation and excessive mucus retention that are accompanied by airway obstruction. They include chronic obstructive ...

Study reveals surprises concerning COPD and smoking

March 22, 2017
A new study challenges the widely accepted but oversimplified description of airway inflammation in smokers and patients with chronic obstructive pulmonary disease (COPD).

Recommended for you

How drug resistant TB evolved and spread globally

October 17, 2018
The most common form of Mycobacterium tuberculosis (TB) originated in Europe and spread to Asia, Africa and the Americas with European explorers and colonialists, reveals a new study led by UCL and the Norwegian Institute ...

Researchers cure drug-resistant infections without antibiotics

October 17, 2018
Biochemists, microbiologists, drug discovery experts and infectious disease doctors have teamed up in a new study that shows antibiotics are not always necessary to cure sepsis in mice. Instead of killing causative bacteria ...

Infectious disease consultation significantly reduces mortality of patients with bloodstream yeast infections

October 17, 2018
In a retrospective cohort study conducted at the University of Alabama at Birmingham Division of Infectious Diseases, patients with candidemia—a yeast infection in the bloodstream—had more positive outcomes as they relate ...

Marker may help target treatments for Crohn's patients

October 16, 2018
Crohn's disease (CD), a chronic inflammatory condition of the intestinal tract, has emerged as a global disease, with rates steadily increasing over the last 50 years. Experts have long suspected that CD likely represents ...

Study traces hospital-acquired bloodstream infections to patients' own bodies

October 15, 2018
The most common source of a bloodstream infection acquired during a hospital stay is not a nurse's or doctor's dirty hands, or another patient's sneeze or visitor's cough, but the patient's own gut, Stanford University School ...

Polio: Environmental monitoring will be key as world reaches global eradication

October 15, 2018
Robust environmental monitoring should be used as the world approaches global eradication of polio, say University of Michigan researchers who recently studied the epidemiology of the 2013 silent polio outbreak in Rahat, ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.