On the Throne with the Flu

Newswise — Flu infection has long-ranging effects beyond the lung that can wreak havoc in the gut and cause a dreaded symptom, diarrhea, according to a study published in The Journal of Experimental Medicine.

Gastrointestinal symptoms are often seen with flu infection, but because the virus only grows in lung cells, it’s unclear how intestinal symptoms develop. Researchers in China now show that flu infection in mice prompts responding immune cells in the lung to alter their homing receptors, causing them to migrate to the gut. Once there, they produce the antiviral mediator IFN-γ, which alters the natural composition of gut bacteria. In turn, the bacterial changes lead to inflammation that promotes tissue injury and diarrhea. Blocking inflammatory molecules in the intestine or treating mice with antibiotics to deplete bacteria attenuated flu-induced intestinal injury without affecting immune responses in the lung.

Why some flu infected patients develop gastrointestinal symptoms while others do not remains unknown. However, these findings suggest ways to directly relieve intestinal symptoms like diarrhea during flu infection without interfering with the body’s ability to fight the virus in the lung.

Wang, J., et al. 2014. J. Exp. Med. doi:10.1084/jem.20140625

About The Journal of Experimental MedicineThe Journal of Experimental Medicine (JEM) is published by The Rockefeller University Press. All editorial decisions on manuscripts submitted are made by active scientists in conjunction with our in-house scientific editors. JEM content is posted to PubMed Central, where it is available to the public for free six months after publication. Authors retain copyright of their published works and third parties may reuse the content for non-commercial purposes under a creative commons license. For more information, please visit www.jem.org .

Research reported in the press release was supported by the Ministry of Science & Technology of China, Natural Science Foundation of China, Fundamental Research Funds for the Central Universities, and China Postdoctoral Science Foundation.