Before you reach for that bottle of aspirin when you have a cold, you may want to consider the result of a new study on fever. Researchers have found that running a slight temperature bolsters the immune system, and might actually help people with colds and other infections recover more quickly.

Experts say little has been known about the role body temperature plays in disease. For example, do people run a fever because their immune systems are working hard to make them well? Or is an elevated temperature part of the healing process?

"Studies from our group and from others really raise the concept that in moderate ranges, the febrile temperature is providing just one more advantage to the immune response, the immune defense," said Sharon Evans.

Sharon Evans of Roswell Park Cancer Institute in Buffalo, New York.

Evans says in a healthy individual the body deposits about a 100,000 disease-fighting white blood cells every day into each lymph node, which is part of the body's immune system.

These white cells, or lymphocytes, act as sentinels for infection. To gain entry into the nodes, the cells must cross delicate blood vessel tissue and membranes of the lymph system.

But when there is a local infection or cold that requires a heightened immune response, a flood of white cells pack the lymph glands.

Evans and colleagues conducted a study looking more closely at this process, and the role fever plays since it accompanies infection.

The researchers used mice whose core body temperature was raised to about 39.5 degrees Celsius, that of an average fever.

Evans says investigators found that elevations in body temperature doubled the speed at which the infection-fighting white blood cells entered the lymph system.

"In other words, more lymphocytes are coming through constantly and searching for foreign pathogens," she said. "So, the overall efficiency of immune defense is actually augmented."

The findings were published in the journal Nature Immunology.

Evans says future studies may show it is beneficial not to reduce a fever.

"It may not be necessary to repress a fever in the early stages of infection as long as it's well-controlled," noted Sharon Evans. "The issue becomes when it is very, very high, and you know that is talking above 105 degrees [40 Celsius], above the temperatures we used in our study. Then you always have concerns, especially in children, that you might have real problems in the brain and other organ failure systems."

Evans says she always recommends that people listen to their doctors when it comes to dealing with high fevers.