Editorial Article: Clinical proteomics: Identifying biomarkers to predict patient risk of COVID-19

How Radboud University Medical Center researchers have identified protein biomarkers linked to COVID-19 infection

29 Jun 2020

Prof. Leo Joosten is Head of Research, Department of Experimental Medicine and Professor of Mechanisms of Inflammatory Disease at Radboudumc, Nijmegen, The Netherlands

The 2020 COVID-19 pandemic has spurred research efforts from scientists worldwide to understand the SARS-CoV-2 virus and how we might treat and prevent infection. In this SelectScience interview, we speak with inflammatory disease expert Prof. Leo A.B. Joosten to learn how researchers at Radboudumc, Nijmegen, The Netherlands, are working to identify biomarkers of the disease, its mechanisms of infection and the impact of immune response, to ultimately search for possible treatments and vaccination approaches. 

A change of direction

During the pandemic, hospitals such as Radboudumc have diverted resources to accommodate patients with severe COVID-19 infections. While this, along with government rules to prevent the spread of COVID-19, have meant that many research projects are on hold — including Joosten’s work on gout and Lyme disease — the situation has also provided the opportunity for scientists at the university to begin interesting and important studies into the coronavirus. 

Radboudumc has now developed a database of more than 1100 COVID-19 patient samples. “They have a very good clinical database now. So, we know a lot more about these patients,” says Joosten. Studies into clinical biomarkers of COVID-19 infection and how these might be used to identify the most vulnerable patients are now underway, as well as research into the mechanisms of severe lung inflammation and two vaccination trials to determine the impact of boosting the immune system using a BCG vaccination could have in protection against the virus.

Predicting who’s at risk

One major project for the Radboud Center for Infectious diseases (RCI) COVID-19 study group is to find biomarkers of COVID-19 pathophysiology that can be used to identify the patients most at risk of developing severe lung inflammation and if these could be therapeutic targets. “As soon as the first patients could come to the hospital, we started collecting a biobank of samples,” explains Joosten. “We wanted to see if we could already predict something – if the patients come from the GP to the hospital, can we already make a decision? Who will develop severe symptoms and who will go to the ICU, and will they survive or die?”

Using samples from over 1,100 patients with COVID-19 from several hospitals in the south of the Netherlands, the laboratory of experimental medicine is investigating inflammation biomarkers to see how they may correlate with the different time points of the patient’s journey and if these could be potential targets for therapeutic treatment of the infection. 

Detecting changes with targeted proteomics

To carry out this work, the group has collaborated with Olink Proteomics to analyze samples using Olink® Inflammation protein biomarker panels. This novel, high-throughput multiplex immunoassay technology has enabled the group to analyze 92 inflammation-related protein biomarkers across 96 samples simultaneously in a range of sample types. “This is a very robust system – it works across plasma, serum and supernatant,” Joosten shares. The biomarker panel also provides advantages for studies dealing with limited amounts of sample. “The small volume is very interesting because you need only 5 to 10 microliters,” says Joosten.

In addition to the inflammation biomarker panel, they are also investigating biomarkers that may explain why obesity appears to be a risk factor in developing severe COVID-19 infection, using Olink’s Cardiometabolic (92 biomarkers) and Cardiovascular II (92 biomarkers) panels. Joosten explains: “We're also interested in cardiovascular disease and metabolic disease because of the link to obesity.”

The first paper of the RCI-COVID-19 study group describes changes in inflammatory pathway protein biomarkers that may be able to identify whether a patient will experience severe symptoms and end up in intensive care or not.1 The study found that interleukin (IL)-6, complement and kinin-kallikrein pathways were dysregulated in patients with severe SARS-CoV-2 infection. The work identified several differences in patients that require intensive care, for example, proinflammatory cytokine IL-6, several chemokines and hepatocyte growth factor were found to increase in circulation in patients that entered ICU compared to those that did not, while stem cell factor and inhibitors of the kinin-kallikrein pathway were found to be downregulated.
These findings indicate predictors of patient outcome and identify targets for potential immunotherapy treatment.

Looking to the future

As many countries are now thought to be over the initial peak of the coronavirus outbreak and social distancing control measures begin to be lifted there are concerns that the virus may peak again. “I think it's really important that we don't have a second wave,” says Joosten. “If there is a second wave then we may experience even more problems, because not only are the hospital employees exhausted, the resources are also exhausted.” 

There are also other opinions that suggest the virus may take a different course, as Joosten explains: “We could also see virulence of the virus decrease so that people are still affected but not severely sick anymore. So, for the virus, it is easy to spread to populations, but people do not die from it. And that would also be a very nice development if that happens.”

For now, work at Radboud University Medical Centre continues to focus on protecting people from developing the severe complications of COVID-19 infection that can cause death, such as lung inflammation. But, ultimately a vaccine is essential. “We need a vaccine - it doesn’t have to be a perfect vaccine, just as long as it protects from severe complications. Because this pandemic affects the whole world and it is devastating a lot of lives,” Joosten concludes.

About Prof. Leo Joosten

A pathologist by training, Prof. Leo Joosten is Head of the Research Laboratory of Experimental Medicine, Department of Medicine, and Professor of Mechanisms of Inflammatory Disease at Radboud University, Nijmegen, The Netherlands.

With over 600 publications, Joosten’s research expertise lies in inflammation-related conditions and diseases including rheumatoid arthritis and gout. Current work in Joosten’s department also covers metabolic disease such as diabetes and cardiovascular disease, infection-related inflammation, endocrinology, and cancer, as well as infectious diseases including fungal, bacterial and viral infections.



1. van de Veerdonk FL, Janssen AF, Grondman I, de Nooijer AH, Koeken VACM, Matzaraki V, Boahen CK, Kumar V, Kox M, Koenen HJPM, Smeets RL, Joosten I, Brüggemann RJM, Kouijzer IJE, van der Hoeven HG, Schouten JA, Frenzel T, Reijers M, Hoefsloot W, Dofferhoff ASM, Kerckhoffs APM, Blaauw MJT, Veerman K, Maas C, Schoneveld AH, Hoefer IE, Derde LPG, Willems L, Toonen E, van Deuren M, van der Meer JWM, van Crevel R, Giamarellos-Bourboulis EJ, Joosten LAB, van den Heuvel MM, Hoogerwerf J, de Mast Q, Pickkers P, Netea MG. A systems approach to inflammation identifies therapeutic targets in SARS-CoV-2 infection. medRxiv. 2020. [Forthcoming]