Australian researchers find the key to treating chronic inflammation in severe Covid-19

Researchers from the University of Queensland (UQ) are one step closer to finding treatments for the prevention of inflammation in severe Covid-19, after completing studies into how immune cells respond to the virus.

Working with Dr. Sarah Londigran from the Peter Doherty Institute for Infection and Immunity, Dr. Larisa Labzin and Professor Kate Schroder from UQ’s Institute for Molecular Bioscience (IMB), have revealed that the majority of immune cells contributing to chronic inflammation, are not infected with the SARS-CoV-2 virus that causes Covid-19.

Dr. Labzin suggests that these uninfected cells, called macrophages, identify damage and death in neighbouring cells and trigger a significant inflammatory response, rather than setting off a “protective response to eliminate the disease”.

“There is an imbalance in the immune response because most macrophages are not infected with the virus,” Dr. Labzin said.

“We end up with too many immune cells coming to the site of infection causing a whole lot of collateral damage – too much inflammation and not enough virus fighting.

“It's a double-edged sword for the body: the immune system tackling an infectious disease early on is protective, but when it's prolonged or excessive, it can really drive chronic inflammation.”

Currently researching how to target macrophages selectively, the IMB team hopes to find a method of doing so without jeopardising the body’s ability to fight the virus, with the aim of reducing the occurrence of severe Covid-19.

Currently given to patients hospitalised with Covid-19, at the peak of the virus, anti-inflammatory drugs are used to ease the overactive immune response, however research suggests that the anti-inflammatory drugs can lead to secondary infections.

With this new information on macrophages, the researchers hope to develop anti-inflammatory drugs that can be taken in the earlier stages of the infection, to prevent severe inflammation.

Professor Kate Schroder said that in order to put up a more strenuous fight against infections, further studies into the fundamental biology into the immune system are required.

“We have vaccines and anti-virals in the fight against COVID-19 but the virus keeps mutating, so this is a way to future-proof ourselves against new variants and also future pandemics and infections.”

The research was funded by the National Health and Medical Research Council, and was published in Science Signalling.