Why Sleep Soothes The Flu

A special protein enhances sleep’s healing power and speeds flu recovery.

Inside Science Television

(Inside Science) – How many times has a grandmother recommended sleep to calm the flu? Now, science is showing that she’s right – thanks to help from a special brain protein. The finding could lead to some novel treatments to help the body fight the flu virus, sprayed right up the nose.

“We’ve known for a long time that microbes affected sleep, at least superficially – Hippocrates even wrote about sleep 2,500 years ago,” said James Krueger, a researcher at Washington State University in Spokane, Washington.

Krueger showed that a brain-specific protein called AcPb speeds recovery in lab mice by promoting the healing power of sleep. When he infected mice that lacked the protein with the influenza virus H1N1 – the strain that was common in the 2009 flu season -- their symptoms were more severe and they died at higher rates. Mice that had the brain protein slept more, and recovered more quickly from the flu.

The research also looked at the way that AcPb interacted with an immune system that is signaling a chemical known as interleukin-1. Interleukin-1 is a family of cytokines, which are inflammatory molecules that cause people to feel lousy when sick with the flu.

When the brain protein links up with the inflammatory molecule in healthy animals, it helped to regulate their sleep. Prior research has shown that sleep keeps the immune system healthy and is vital to the body’s ability to battle all kinds of infections. The research was published recently in the journal Brain, Behavior and Immunity.

The finding still leaves a question for the researchers, since influenza is typically viewed as an illness of the lungs, not the brain.

“The virus doesn’t replicate in brain, so the big question is why is this doing this in the brain?” Krueger asked. “Why is a brain protein improving a lung disease?”

The next steps in the research are to harness the brain protein’s soporific powers to develop new methods of treating the flu.

Axel Steiger, director of the sleep laboratory at Germany's Max Planck Institute of Psychiatry, in Munich, said that the work is important because it connects the basic science of sleep regulation with a clinical application – better therapies for infectious diseases.

“Influenza is maybe not seen as such a spectacular disease like Ebola, but it’s a serious disease with high death rate and a high morbidity in many countries, and so it would be very useful to have new therapies,” Steiger said. He added that there was no reason this brain protein is limited to helping the flu -- it may be found to help other infectious diseases as well.

“It’s an example of nature working for you – with an infection, patients often become sleepy, and on the other hand, sleep helps to recover,” said Steiger.

Krueger said it’s vitally important to get new defense forces to fight the flu.

“Influenza is a tough nut to crack and sooner or later the virologists say we’re overdue for a pandemic for influenza,” he said. “This is one tiny contribution in a bigger endeavor. We don’t have a lot of artificial defense mechanisms that we can offer people.”

Other studies have shown that acute illnesses are more frequent in teenagers who sleep less (or miss sleep several nights in a row) and that people who have insomnia have lower flu antibody counts – both before and after getting a flu vaccine.

Lower antibody counts make the flu vaccine less effective, explained Kimberly Kelly, an associate professor of psychology at the University of North Texas in Denton, Texas. “It’s not totally surprising,” laughed Kelly. “There is a ton of data showing the effects of sleep deprivation on illness.”

Krueger, who was sick with the flu at the time of the interview, cautioned that while work in humans is still years off, treating mice is the first step. “This whole area is quite a ways – years away -- from a successful treatment of humans. Hopefully someone will pick it up quickly so they can cure me.”