In one of the biggest breakthroughs in schizophrenia research in recent times, Professor Cyndi Shannon Weickert at Neuroscience Research Australia (NeuRA) has identified immune cells in greater amounts of some people with schizophrenia. The study published in *Molecular Psychiatry has the potential to transform global schizophrenia research and open new avenues for developing targeted immune cell therapies.

To understand the significance of this discovery Professor Shannon Weickert says you first need to understand that most scientists have had a long held a belief that immune cells were independent from the brain pathology in psychotic illness.

“In our study, we challenged this assumption that immune cells were independent of the brain in psychiatric illness and made an exciting discovery. We have identified immune cells as a new player in the brain pathology of schizophrenia said Professor Shannon 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 Professor Shannon Weickert and her team identified the presence of a fourth type of cell in the brain tissue of people with schizophrenia who show high levels of inflammation: macrophages a type of immune cell.

“Immune cells have previously been ignored as they had long been viewed simply as travelers just thought to be passing by, undertaking some sort of surveillance work. They have never been a suspect until now,” said Professor Shannon Weickert.

“To find immune cells along the brain barrier in increased amounts of people with schizophrenia is an exciting discovery. It suggests that immune cells themselves may be producing these inflammatory signals in the brains of people living with schizophrenia.”

“We have observed that in people with schizophrenia, the glial cells, one of the local residents, become inflamed and produces distress signals which change the status of the endothelial cells, said Professor Shannon Weickert.

“So what we think this may mean is that the endothelial cells extend sticky tentacles, so when the immune cells travel by, some are captured and may transmigrate across the blood brain barrier, entering the brain in greater amounts in some people with sci compared to people without the disorder.

With Professor Shannon Weickert’s graduate student Helen Cai as first author.

This 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.

One in every 100 Australians are living with schizophrenia. No single cause for 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.

This new discovery has the potential to change the direction of schizophrenia research. Prof SSW is encouraging a cross-collaborative approach between neuroscientists and immunologists globally, to work together to develop treatments targeting this abnormal immune pathology of schizophrenia”.

“This opens whole new avenues for therapy, because it suggests that the pathology of schizophrenia could be within the immune cells and that the immune cells could be contributing to the symptoms of schizophrenia.”

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