Posted on Feb 23, 2012, 6 a.m.
Certain strains of Pseudomonas aeruginosa cause white blood cells to produce very high levels of histamine, which in turn leads to inflammation, a hallmark symptom of asthma.
Pseudomonas aeruginosa is a common bacterium found in soil, water, skin flora, and most man-made environments throughout the world. University of California/San Francisco (UCSF; California, USA) researchers have established an eye-opening connection between this common environmental bacteria and airway inflammation. George Caughey and colleagues studied the effect of specific strains of Pseudomonas bacteria in a laboratory model of neutrophils (a type of white blood cell). The team observed that one strain produced substances that cause the neutrophils to increase their production of histamine, a pro-inflammation compound. Further, the researchers observed that the bacteria strain prompted neutrophils to make much more of a key enzyme in histamine synthesis (histidine decarboxylase), thereby elevating histamine levels. The study authors conclude that: "These findings raise the possibility that Pseudomonas-stimulated neutrophils can enhance airway inflammation by producing histamine.”
Xiang Xu, Hong Zhang, Yuanlin Song, Susan V. Lynch, Clifford A. Lowell, Jeanine P. Wiener-Kronish, George H. Caughey. “Strain-dependent induction of neutrophil histamine production and cell death by Pseudomonas aeruginosa.” J Leukoc Biol., February 2012, 91:275-284.