Cells predict West Nile virus infection

SAN FRANCISCO, Oct. 13 (UPI) -- A U.S. study has found levels of certain immune cells can predict whether a person or mouse infected with the West Nile virus will develop symptoms.

Infection with the West Nile virus causes no symptoms in most people, although it can cause fever, meningitis and-or encephalitis in others, scientists said. What determines the outcome of infection in different people has not yet been determined.

In the new study, Philip Norris and colleagues at the Blood Systems Research Institute in San Francisco discovered levels of immune cells known as Tregs in the blood of a human or mouse infected with the virus predict whether the person or the mouse will develop symptoms of infection.

The researchers said their findings suggest higher levels of Tregs in the blood after infection with the virus protect against severe disease in individuals with a fully functioning immune system.

The study appears in the Journal of Clinical Investigation.