Australian scientists have found immune cells in the brain...

Australian scientists have found immune cells in the brain tissue of some people with schizophrenia.
These immune cells, called macrophages, can mess with neurons and damage tissue.
The breakthrough opens doors to new areas of research and drug development.
As a type of immune cell, it has always been considered one of the good guys. But in a stunning breakthrough in schizophrenia research, scientists say the "macrophage" immune cell can go rogue, causing havoc in the brain.
"Macrophage" means "big eaters" in Greek and is a fitting name for the cell because - when behaving - it digests cellular debris and foreign substances.
Most scientists have long held a belief that red, white and immune blood cells are independent from the brain pathology in psychotic illnesses. However Australian researchers have now found that some people with schizophrenia have increased immune cells.
Australian researchers have, for the first time, identified the presence of macrophage cells in the brain tissue of a subgroup of people with schizophrenia.
"It's like a murder mystery, one that’s remained unsolved for a hundred years," Professor Cyndi Shannon Weickert from Neuroscience Research Australia (NeuRA) said.
"All of a sudden a new suspect is recognised, an individual that was actually there at the scene of the crime at the time the crime was committed ... a new culprit that could be triggering schizophrenia."
Advertisement
An estimated 100,000 Australians have psychosis, a complex brain disorder that triggers delusions and hallucinations. No single cause has been identified, preventing the development of a cure.
Experts have long thought there were three key figures in the mystery - the neuron (a nerve cell), the glial (a cell that supports neurons) and the endothelial cell, which coats the inner surface of blood vessels.
Professor Cyndi Shannon Weickert, NSW Chair of Schizophrenia, is pictured in the laboratory where her groundbreaking discovery was made.
In a study published in Molecular Psychiatry, NeuRA researchers say they have identified a fourth player - the macrophage immune cell - in the brain tissue of people with "high inflammation" schizophrenia, a subgroup that accounted for 40 per cent of their overall sample.
“To find immune cells along the blood brain barrier in increased amounts in people with schizophrenia is an exciting discovery," Professor Weickert said.
"It suggests immune cells themselves may be producing these inflammatory signals in the brains of people living with schizophrenia.”
She believes the "angry" glial cells outside the blood vessel are emitting distress signals and causing endothelial cells to change shape and capture immune cells.

NeuRA scientists have found immune cells in the brains of people with 'high inflammation' schizophrenia.
"These cells may transmigrate across the blood brain barrier entering the brain in greater amounts in some people with schizophrenia compared to people without the disorder,” she said.
Immune cells can enter the brain to conduct "immune surveillance", but normally re-enter the bloodstream or die. At this stage, the researchers are not sure if immune cells in the brain are helpful or harmful.
Scientists are still debating whether "inflammation in the brain" exists, as inflammation usually refers to the swelling and redness - signs of the body's immune response to an injury or infection - seen in tissue close to the skin, not underneath the hard bone structure of the cranium.
Professor Weickert said the findings suggested that schizophrenia researchers should be working with immunologists to develop treatments that target the immune system.
"We could block entry of these immune cells into the brain to see if that improves the life-disabling symptoms people from schizophrenia often suffer from," she said.
Professor John McGrath from University of Queensland said NeuRA had made a "convincing case" that inflammatory processes were involved in a subgroup of people with schizophrenia.
Add to shortlist
"This is an important finding, as it may help us ‘pull apart’ the poorly understood syndrome of schizophrenia, and hopefully guide more targeted or precision treatments," he said.
Professor Christos Pantelis from University of Melbourne said the possibility that inflammation played a key role was a very topical issue.
"It is an intriguing finding that will require further replication and validation," he said. "It remains to be clarified how important an immune-related response is in schizophrenia."
Professor Weickert is on an advisory board for pharmaceutical company Lundbeck and receives a research grant from Astellas Pharma.