Breakthrough shows immune cells may play a role in schizophrenia

By Dr. Ananya Mandal, MDSep 14 2018

A type of immune cell called the “macrophages” are known to be one of the first soldiers of the body that can fight off infections and plays a role in maintaining immunity and in inflammation. According to latest research in schizophrenia, these macrophages can become altered and may cause changes in the brain leading to changes in the brain similar to schizophrenia.

The term “macrophage” in Greek literally means “big eater”. These cells are capable of eating up or engulfing foreign bodies, infective cells, debris etc and generally maintain the housekeeping within the body. These cells function as first line soldiers when the body encounters an infection.

Schizophrenia breakthrough. Image Credit: Neuroscience Research Australia

Australian researchers have now found that among people with schizophrenia the number of these immune cells within the brain is raised. This is the first time that such a fact has been demonstrated say the experts. Professor Cyndi Shannon Weickert from Neuroscience Research Australia (NeuRA) said in a statement that this was an “unsolved mystery for a hundred years” and now it is solved. She said that this “new suspect” is detected to be present at the “scene of crime” when it was committed. She called the macrophages, “a new culprit that could be triggering schizophrenia.” The study results appear in the latest issue of the journal Molecular Psychiatry.

Schizophrenia is a psychotic brain disorder typically characterized by audio and visual hallucinations and delusions. According to the statistics nearly 100,000 Australians have psychosis. Na definite causes are known and no cure has been developed yet. Till date neurons or nerve cells, glial cells that support the neuron and endothelial cells that coat the inner walls of the blood vessels have been studied for possible mechanisms of psychosis and schizophrenia. The NeuRA researchers have now come up with the fourth compenent that could cause or trigger schizophrenia.

The team found that in their subgroup of schizophrenics, 40 percent showed high levels of inflammation in their brains. Professor Weickert explained, “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. She explained that the triggered glial cells could be signalling the endothelial cells of the blood vessels to alter their shapes and to call for the immune cells and capture them. These immune cells can now “transmigrate” past the blood brain barrier to enter the brain she said. The numbers are seen to be higher among those with schizophrenia compared to normal humans.

At this stage of the research is not known if the immune cells are “harmful” or “helpful”. Professor Weickert said, what is clear is that schizophrenia researchers need to collaborate with immunologists to develop target therapies for schizophrenia. She said that may be if the immune cell movement to the brain were stopped, there could be improvement in the condition. More studies in future could help provide answers to the question say experts.

Source: https://www.nature.com/articles/s41380-018-0235-x