Gene Tied to Out-of-Control Immune Response

A gene called auf1 seems to protect against septic shock in mice, a new study finds. Animals lacking the gene were more likely to undergo shock, suggesting that the gene helps keep the immune system's response to infections in check. Researchers hope to discover whether different forms of auf1 and related genes make people more likely to suffer autoimmune disease or life-threatening reactions to infections such as anthrax or flu.

Infectious organisms trip specialized immune cells in the body and cause them to pump out proteins called cytokines, which produce inflammation and other hallmarks of infection, such as chills and fever. The body must carefully regulate its cytokine response, however, because "if it isn't turned off it can lead to septic shock and rapid death," says microbiologist Robert Schneider of New York University. Septic shock, which causes 9 percent of deaths in the U.S. each year, occurs when the immune reaction to a bacterial infection grows out of control, shutting down organs and sending blood pressure plummeting. Researchers think similar effects contribute to death from anthrax and pandemic flu.
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