Detection of a new autoimmune syndrome related to COVID-19 causing deadly lung disease

A spike in cases of a rare autoimmune disease during the COVID-19 outbreak in the UK has led to the discovery of a new syndrome. It's a new autoimmune syndrome linked to COVID-19 that can cause life-threatening lung disease.

The syndrome - which scientists call "MDA5 Interstitial Pneumonia and Autoimmune COVID-19", or MIP-C for short - is a rare, serious condition in which the immune system Immunity accidentally attacks the body. In the worst case scenario, the lungs will be so scarred and stiff that the only way to save them is a full lung transplant.

Scientists say they have discovered an autoimmune syndrome potentially linked to COVID-19. (Photo: Christoph Burgstedt/ Science Photo Library)

However, only a small fraction of cases involve the lungs. Dr Dennis McGonagle, a rheumatologist at the University of Leeds in the UK who first began studying models of the new disease, said: 'Two-thirds of the cases studied did not have lung disease. But we found that eight cases progressed rapidly and died despite all the high-tech therapies we were able to give them."

In total, McGonagle and his colleagues have so far identified 60 cases of the syndrome. They published this study in the May issue of eBioMedicine.

The disease looks similar to the known condition MDA5 dermatomyositis , which occurs mostly in women of Asian descent, McGonagle said . In them, patients suffered from joint pain, muscle inflammation and skin rashes, and in two-thirds of cases, they suffered life-threatening lung scarring. MDA5 dermatomyositis occurs when the immune system attacks one of its own proteins: a protein called MDA5 that normally helps detect RNA viruses. These viruses include those that cause influenza, Ebola and COVID-19.

McGonagle said new research shows that exposure to coronavirus RNA, Covid-19 vaccines or both can sometimes trigger the production of anti-MDA5 antibodies.

Normally, MDA5 activates when it senses viral RNA in cells and prompts the body to produce antibodies against the virus. But in people with MIP-C, this immune response malfunctions. McGonagle suggests that either the body mistakes the MDA5 protein for a foreign protein and attacks it, or the RNA triggers an immune response so strong that the body's own proteins, including MDA5, become the target of the immune attack.

The researchers found that IFIH1 activation was accompanied by high levels of an inflammatory protein called interleukin-15 (IL-15) . IL-15 activates a class of immune cells that usually kill infected cells but can sometimes attack the body's own cells.