What are ‘autoantibodies’ in the body’s immune system response to COVID-19?

3d rendered image of a blood vessel which contains both red blood cells and coronavirus cells
Alex Richter, Professor of Clinical Immunology at BHP founder-member the University of Birmingham, discusses the results of a study that looked at patients who have recovered from COVID-19 and what the presence of autoantibodies (a type of antibody produced by the immune system that is directed against their body’s own tissues or organs) means.

Video transcription

Many patients with Covid19 produce immune responses against their own body’s tissues or organs. My name is Professor Alex Richter, I’m a Professor of Clinical Immunology at the University of Birmingham, and we’ve been running a research study looking at the development of these immune responses in patients with Covid-19. 

We’ve looked at four groups of patients: those who are really unwell with Covid on the intensive care unit;  patients following recovery from the intensive care unit three or four months later; and patients who’ve had milder disease so they’ve had Covid19 in the community and haven’t needed to come to hospital. And then to compare these Covid patients, we’ve  also looked at other patients from intensive care that have been there for another reason, like another infection or a severe operation, and what we found is that patients in all of the Covid groups have a high number of what we call  autoantibodies.

Antibodies are important parts of the immune system generated to clear infection, but when the body goes slightly wrong it can misfire and the immune system recognises itself – its own tissues or organs – and we call those autoantibodies.

What we found is that patients who are really unwell with Covid have much higher numbers of autoantibodies than those with milder disease, and that these  antibodies don’t just happen at the time of the acute infection; that they’re  long-lasting, so we are finding these autoantibodies three to six months after the infection.

When we looked at the ITU patients who didn’t have Covid, we found that a number of them did have autoantibodies but at a much lower rate than the patients who are on intensive care with Covid19. So that suggests that acute illness is able in some way to generate an immune response where the body attacks itself, but this seems to be a much bigger problem with Covid19.

So, why did we look to do this study in the first place?

What we found is a number of unexplained symptoms in Covid19, both when patients are really unwell and in the community. We’ve found a number of patients that may have problems with their heart or severe fatigue or severe muscle problems, and we see these symptoms in patients with known autoimmune diseases. What we decided to do was to look and use the tests that we usually use in a clinical setting to detect patients with these autoimmune heart or muscle problems or skin problems, and undertake these tests in the Covid patients. The test that we found that are most commonly positive are autoantibodies that affect the heart, the muscles, and the skin, and these fit with what we are finding in Covid19 patients in convalescence.

So, this doesn’t necessarily mean that these antibodies are causing disease, but we have a really interesting observation here and what we now need to do is we need to  look at patients over a period of time who develop symptoms – either during acute Covid or in recovery from Covid – and we need to see whether these autoantibodies are directly associated with the clinical symptoms that these patients are suffering from. If we can make that clinical link between the antibodies and the patient’s symptoms, we can then start to screen patients for these autoantibodies. So we’re going to hopefully be working with some of the national collaborations who have these long-term treatments so we hopefully will be able to have an answer within the next few months as to whether this is the case and this then offers the exciting possibility that we may be able to intervene with treatments going forward.