Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

White blood cells in lung produce histamine seen in allergies

17.01.2007
First evidence that neutrophils, or any cell other than mast cells, produce histamine in significant quantities in mouse study

In a surprise finding, scientists have discovered that histamine, the inflammatory compound released during allergic reactions that causes runny nose, watery eyes, and wheezing, can be produced in large amounts in the lung by neutrophils, the white blood cells that are the major component of pus.

Pus, a fluid found in infected tissue, is produced as a result of inflammation.

The study in mice is the first to show that lung neutrophils can produce histamine in significant quantities, according to principal investigator George Caughey, MD, chief of pulmonary/critical care medicine at the San Francisco VA Medical Center.

"Previously it was thought that the primary sources of lung histamine, in health as well as disease, was mast cells, which are classically associated with allergy," notes Caughey, who is also a professor of medicine at the University of California, San Francisco.

Caughey says the result could mean that histamine acts as a link between airway infections and asthma and bronchitis, which are associated with allergy. "In both, we observe inflammation –– swelling, blood vessel leak, and muscle contraction that narrows the airway."

The study appears in the January 2007 issue of the Journal of Experimental Medicine.

Caughey was investigating the well-known fact that upper respiratory infections often trigger acute asthma attacks. "We hypothesized that an infection in the airway would release histamine from mast cells, and that would be one of the reasons," he explains.

To test the hypothesis, Caughey and his team exposed two different populations of mice to mycoplasma, a common respiratory infection in rodents and humans. One population had a genetic abnormality that causes a total lack of mast cells; the other population was made up of normal, wild-type mice. Both populations of infected mice developed pneumonia.

"We thought the mice without mast cells would do better than the wild-type mice, because the infection wouldn't be provoking mast cells to release histamine," recalls Caughey. "In fact, they did much worse. Even though there were no mast cells, histamine levels rose up to 50 times normal."

The reason was straightforward, Caughey says. Neutrophil numbers increased in response to infection, and neutrophils in turn produced histamine. "It's a direct effect of the mycoplasma bacteria on neutrophils. They induce neutrophils to produce the enzyme that produces histamine."

Individual neutrophils produce much less histamine than individual mast cells, says Caughey, but "because pus contains millions if not billions of neutrophils, the overall amount they make is very considerable."

The neutrophil-histamine effect was similar in the wild-type mice, reports Caughey: "Histamine levels from neutrophils blew right past the histamine levels contributed by mast cells."

The wild-type mice suffered less severe infections overall because "as a number of recent studies, including ours, have shown, mast cells actually play a role in protecting against bacteria," Caughey explains. "For example, a mouse without mast cells with the equivalent of a ruptured appendix will die of the resulting infection, while a mouse with mast cells can survive."

When the infected mice without mast cells were given antihistamines, the level of histamine, and therefore the severity of the pneumonia, dropped in proportion to the amount of antihistamine given.

"This is a study in mice, so we cannot freely extrapolate the results to human beings," cautions Caughey. "Nonetheless, antihistamines may deserve more of a look as therapeutic options in lung and airway infection."

He says the study also has implications for other types of airway infection "in which there are a lot of white blood cells –– cystic fibrosis, for example, which can be associated with asthma-like airway contraction."

The next steps for Caughey and his research team are to investigate "how general this result might be. Does only one type of bacteria cause the effect, or do others, also? Is it limited to rodents, or does it carry forward to humans? And if it does, is the amount of histamine produced by neutrophils enough to make a clinical difference?"

Steve Tokar | EurekAlert!
Further information:
http://www.ncire.org
http://www.ucsf.edu/

Further reports about: Caughey antihistamine histamine mast cells neutrophils

More articles from Life Sciences:

nachricht Helping to Transport Proteins Inside the Cell
21.11.2018 | Albert-Ludwigs-Universität Freiburg im Breisgau

nachricht UNH researchers create a more effective hydrogel for healing wounds
21.11.2018 | University of New Hampshire

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: First diode for magnetic fields

Innsbruck quantum physicists have constructed a diode for magnetic fields and then tested it in the laboratory. The device, developed by the research groups led by the theorist Oriol Romero-Isart and the experimental physicist Gerhard Kirchmair, could open up a number of new applications.

Electric diodes are essential electronic components that conduct electricity in one direction but prevent conduction in the opposite one. They are found at the...

Im Focus: Nonstop Tranport of Cargo in Nanomachines

Max Planck researchers revel the nano-structure of molecular trains and the reason for smooth transport in cellular antennas.

Moving around, sensing the extracellular environment, and signaling to other cells are important for a cell to function properly. Responsible for those tasks...

Im Focus: UNH scientists help provide first-ever views of elusive energy explosion

Researchers at the University of New Hampshire have captured a difficult-to-view singular event involving "magnetic reconnection"--the process by which sparse particles and energy around Earth collide producing a quick but mighty explosion--in the Earth's magnetotail, the magnetic environment that trails behind the planet.

Magnetic reconnection has remained a bit of a mystery to scientists. They know it exists and have documented the effects that the energy explosions can...

Im Focus: A Chip with Blood Vessels

Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.

Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...

Im Focus: A Leap Into Quantum Technology

Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.

In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Optical Coherence Tomography: German-Japanese Research Alliance hosted Medical Imaging Conference

19.11.2018 | Event News

“3rd Conference on Laser Polishing – LaP 2018” Attracts International Experts and Users

09.11.2018 | Event News

On the brain’s ability to find the right direction

06.11.2018 | Event News

 
Latest News

Helping to Transport Proteins Inside the Cell

21.11.2018 | Life Sciences

Meta-surface corrects for chromatic aberrations across all kinds of lenses

21.11.2018 | Power and Electrical Engineering

Removing toxic mercury from contaminated water

21.11.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>