June 9, 2020
This may be hard to believe–since we are currently so immersed in the current pandemic—but COVID-19 and the virus that causes it, SARS-CoV-2, are still brand new. As such, there are many things we don’t know about it yet. But one thing that has been pretty clear from the outset is that people with underlying conditions tend to be more susceptible to COVID-19 and to fare worse if they get it.
People with lupus have an immune system that mistakenly attacks their own tissues, and some manage their condition with immunosuppressants to calm down the overactive immune response; both factors make them more vulnerable to infection from all types of disease-causing microbes such as bacteria and viruses. But a recent paper in Clinical Immunology reporting on research related to work funded by the Lupus Research Alliance outlines why they may be at greater risk for the SARS-CoV-2 virus in particular.
Viruses work by entering host cells and hijacking them, forcing them to make more viruses. SARS-CoV-2 enters human cells by binding to a protein on the human cell surface called ACE2. Dr. Amr Sawalha at the University of Pittsburgh, along with researchers in China with whom he collaborates, have found that people with lupus produce more of this ACE2 molecule than other people do. People with lupus also produce more of inflammatory cytokines, proteins that can generate a “cytokine storm.” Cytokines are a normal part of an immune response, but an out-of-control storm like this can cause severe damage to the host–the person–in an exaggerated attempt to clear the infection. And stresses to the body, like an infection or a lupus flare, can induce even more of both ACE2 and the inflammatory cytokines, worsening the problem.
Like all new studies, this one has a few caveats. The first is that even though higher levels of ACE2 were found in the cells of people with lupus, the cells examined were blood cells, not the lung cells that SARS-CoV-2 first meets up with and attacks. The second is that an increased susceptibility to SARS-CoV-2 among people with lupus has not yet been documented in terms of controlled observational studies in COVID-19 patients. Some recent case series do however support the conclusion of Dr. Sawalha’s study that the course of COVID-19 might be more severe in lupus patients.
The authors conclude by noting some practical implications of their work. One is that keeping your lupus under control is essential, since lupus flares might increase ACE2 and cytokine production and thus increase the risk of infection with SARS-CoV-2 and worsen the course of the illness. Also, drugs that can decrease ACE2 might provide a way to start to curb this pandemic.
“It is very important that our patients continue to take their lupus medications to prevent lupus from flaring during the pandemic. Call your physician if you experience any new symptoms or symptoms of a lupus flare. Even as some restrictions are being lifted, we recommend that our patients continue to keep a safe physical distance, wash their hands frequently, and wear a mask when they go out,” says Dr. Sawalha.
Watch LRA’s recent webcast to hear more from Dr. Sawalha about lupus and COVID-19 .