Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


White blood cells in lung produce histamine seen in allergies

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:

Further reports about: Caughey antihistamine histamine mast cells neutrophils

More articles from Life Sciences:

nachricht Aquaculture: Clear Water Thanks to Cork
28.10.2016 | Technologie Lizenz-Büro (TLB) der Baden-Württembergischen Hochschulen GmbH

nachricht Bioluminescent sensor causes brain cells to glow in the dark
28.10.2016 | Vanderbilt University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Novel light sources made of 2D materials

Physicists from the University of Würzburg have designed a light source that emits photon pairs. Two-photon sources are particularly well suited for tap-proof data encryption. The experiment's key ingredients: a semiconductor crystal and some sticky tape.

So-called monolayers are at the heart of the research activities. These "super materials" (as the prestigious science magazine "Nature" puts it) have been...

Im Focus: Etching Microstructures with Lasers

Ultrafast lasers have introduced new possibilities in engraving ultrafine structures, and scientists are now also investigating how to use them to etch microstructures into thin glass. There are possible applications in analytics (lab on a chip) and especially in electronics and the consumer sector, where great interest has been shown.

This new method was born of a surprising phenomenon: irradiating glass in a particular way with an ultrafast laser has the effect of making the glass up to a...

Im Focus: Light-driven atomic rotations excite magnetic waves

Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion

Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Steering a fusion plasma toward stability

28.10.2016 | Power and Electrical Engineering

Bioluminescent sensor causes brain cells to glow in the dark

28.10.2016 | Life Sciences

Activation of 2 genes linked to development of atherosclerosis

28.10.2016 | Life Sciences

More VideoLinks >>>