MELBOURNE: People with schizophrenia have greater amounts of immune cells in their brains, scientists have found, paving the way for new therapies to treat the disorder.
The study, published in Molecular Psychiatry, has the potential to transform global schizophrenia research and open new avenues for developing targeted immune cell therapies.
No single cause of schizophrenia has been identified, and this has prevented the development of a cure.
The current treatments for schizophrenia are designed to suppress symptoms rather than target underlying causes of the disorder.
These drugs only partially relieve symptoms and can produce unwanted side effects.
Most scientists have had a long held belief that immune cells were independent from the brain pathology in psychotic illnesses, said Professor Cynthia Shannon Weickert, from University of New South Wales in Australia.
"We challenged this assumption that immune cells were independent of the brain in psychiatric illness and made an exciting discovery.
We identified immune cells as a new player in the brain pathology of schizophrenia," said Weickert.
Current schizophrenia research has focused on the status of three brain cells: the neurons; the glial cells, which support the neurons; and the endothelial cells, which coat the blood vessels.
Employing new molecular techniques allowed researchers to identify the presence of a fourth cell, the macrophage, a type of immune cell in the brain tissue of people with schizophrenia who show high levels of inflammation.
"Immune cells have previously been ignored as they had long been viewed simply as travellers just thought to be passing by, undertaking surveillance work. They have never been a suspect until now," said Weickert.
"To find immune cells along the blood brain barrier in increased amounts in people with schizophrenia is an exciting discovery.
It suggests immune cells themselves may be producing these inflammatory signals in the brains of people living with schizophrenia," she said.
The discovery shows that specific immune cells are in the brains of some people with schizophrenia in close enough proximity to the neurons to do damage.