CHICAGO, March 8 (Xinhua) -- A clinical trial led by researchers at Washington University School of Medicine in St. Louis shows that a drug that revs up the immune system may help treating sepsis.

The trial involved 27 sepsis patients, aged 33 to 82. They were randomly assigned to one of two therapies: seventeen patients received a drug made of interleukin-7 (IL-7), which enhances the proliferation and survival of two types of immune cells: CD4 and CD8; and 10 received a standard treatment.

The study shows that those who received the drug experienced a threefold to fourfold increase in CD4 and CD8 counts. IL-7 boosts adaptive immunity, in which CD4 and CD8 T cells help recruit other immune cells called macrophages, monocytes, neutrophils and dendritic cells to kill bacteria that cause infections.

Standard treatment involves high doses of antibiotics that fight the infection, but they often don't work well and fail to boost the body's immune defenses. As traditional approaches to sepsis therapy do not address the critical problem of patients' severely compromised immune systems, many patients develop lingering infections and are helpless to fight any new infections.

"We know that 40 percent of patients die in the 30- to 90-day period after the initial septic infection," said senior investigator Richard S. Hotchkiss, a professor of anesthesiology, medicine and surgery at the university. "Their bodies can't fight secondary infections, such as the blood infections and staph infections that can develop later on because their immune systems are shot.

"By strengthening adaptive immunity with IL-7 and increasing the numbers of CD4 and CD8 cells available to help fight infections, we think this approach can make a big difference," Hotchkiss added.

Several cancer researchers have begun using IL-7 to rev up a patient's own immune system to fight cancer. In addition, IL-7 has been given to some critically ill patients with serious viral infections and has successfully restored their CD4 and CD8 counts while improving survival.

The findings were published Thursday in the journal JCI Insight.