Researchers at The University of Nottingham have recently suggested that some parasites - such as lice - are important in conditioning our "natural" immune system. Many health problems seen in modern humans today are caused by the body mistakenly attacking its own cells resulting in autoimmune diseases such as arthritis, asthma, diabetes or multiple sclerosis.

The Nottingham researchers believe that some parasites may exert a moderating effect on the function of a key component of the immune system - which could help to reduce overall immune reactivity and the risk of developing immune dysfunctions.

“Our understanding of mammalian immunology is largely based on rodents reared under highly unnatural pathogen and stress-free conditions. Analysing the immune response in wild populations can give crucial insights into how the immune system functions in its natural context", said Jan Bradley, Professor of Parasitology.

Their research, published in the open access journal BMC Biology, links the louse Polyplax serrata to a strong dampening of certain immune responses in wild wood mice collected from a Nottinghamshire forest. The researchers speculate that the louse is able to exert some kind of immuno-suppressive effect, possibly directly by secreting some substance into the mice from its saliva, or indirectly by transmitting bacteria or other pathogens.

Their findings suggest that other mammals, such as modern humans, that develop in artificial environments may have less regulated, overactive immune systems precisely because they are not exposed to parasites throughout their lives.

Professor Bradley went on to say; “Much like laboratory mice, people in developed countries are currently exposed to a very different profile of infections to that encountered by their ancestors. It is possible that the immune dysfunctions we see today are the result of immune systems moulded by evolution for a set of challenges completely different to those encountered in modern times.”

http://communications.nottingham.ac.uk/News/Article/Lice-can-be-nice-to-...