A surge in cases of a rare autoimmune disease during the COVID-19 pandemic in the United Kingdom has led to the discovery of a new syndrome. It's a new COVID-19-associated autoimmune syndrome that can cause life-threatening lung disease.
The syndrome - which scientists have named "Multicenter Interstitial Lung Disease and Autoimmunity in COVID-19" or MIP-C for short - is a rare, severe condition in which the immune system mistakenly attacks the body. In the worst cases, the lungs become so badly scarred and stiff that the only hope of saving the patient is a lung transplant.
Scientists say they have now identified an autoimmune syndrome that could be linked to COVID-19. (Image credit: Christoph Burgstedt/Science Photo Library)
However, only a minority of cases involve the lungs. "Two-thirds of the cases we studied did not have lung disease. But then we found eight cases who went rapidly downhill and died despite all the high-tech treatment we could throw at them," said Dr. Dennis McGonagle, a rheumatologist at the University of Leeds in the UK, who first began investigating the patterns of the new disease.
In total, McGonagle and his colleagues have so far identified 60 cases of the syndrome. They report their findings in the May issue of the journal eBioMedicine.
McGonagle says the condition resembles the known autoimmune condition MDA5 dermatomyositis, which occurs mainly in women of Asian origin. In that condition, patients suffer joint pain, muscle inflammation, and a skin rash, and in two-thirds of cases, they develop life-threatening lung scarring. MDA5 dermatomyositis is triggered when the immune system attacks one of the body's own proteins - called MDA5 - which normally helps detect RNA viruses. These include viruses that cause influenza, Ebola, and COVID-19.
McGonagle says that the new research suggests that exposure to coronavirus RNA, the COVID-19 vaccine, or both may sometimes trigger the production of anti-MDA5 antibodies.
Normally, MDA5 switches on when it senses viral RNA inside cells and sparks the body's production of antibodies against the virus. But in people with MIP-C, this immune response goes awry. McGonagle suggests that either the body mistakes its own MDA5 protein for a foreign protein and attacks it, or the RNA triggers such a strong immune response that the body's own proteins, including MDA5, become collateral damage.
The researchers found that the activation of IFIH1 was accompanied by high levels of an inflammatory protein called interleukin-15 (IL-15). IL-15 activates a type of immune cell that normally kills infected cells but which can sometimes attack the body's own cells.
Summary
A new autoimmune syndrome, called MIP-C, has been linked to COVID-19. The syndrome affects the lungs and can be life-threatening. Research suggests that exposure to coronavirus RNA, the COVID-19 vaccine, or both may trigger the production of anti-MDA5 antibodies, which mistakenly attack a protein in the body called MDA5. This leads to inflammation and damage to the lungs.