Blood plasma: a promising weapon in the fight against COVID-19
24 Aug 2020
At the end of 2019 a previously unknown strain of coronavirus was reported to be causing pneumonia-like disease in human patients in China. Within months this deadly species-jumping virus, given the name severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), had spread into a pandemic that has now killed hundreds of thousands of people around the world.
By August 24th, 2020, when this article was published, the WHO global tally had reached over 23 million confirmed cases of SARS-CoV-2 infection, and 800,906 reported deaths related to the respiratory disease, COVID-19, that it causes.
Much coronavirus research is focused on discovering how SARS-CoV-2 spreads and replicates, and to understand why some infected people develop fatal COVID-19, whereas others develop no symptoms, and the majority of infections cause relatively mild respiratory disease. Industry, academia, non-profit organizations and governments are working to develop drugs and other treatments, alongside preventive vaccines. By August 24th, 2020 the U.S. government’s clinical trials registry listed 3,086 human trials of COVID-19 therapies and vaccines that were under way around the world.
Candidate drug treatments against SARS-CoV-2 infection – or against any harmful virus or bacteria – may include new or existing chemical compounds, as well as biologic molecules such as antibodies or other proteins, which are designed to help the body fight, and minimize damage by, the pathogen. Vaccines, on the other hand, are given to people to prevent infection. They commonly work by triggering the body to produce antibodies that will recognize the pathogen should it try to infect the body at a later time, and rapidly mobilize the immune system to fight the infection before it can cause illness.
Antibodies against SARS-CoV-2 are produced naturally by the immune system during the course of COVID-19 infection. Antibody-containing blood plasma that has been donated by people who have previously recovered from SARS-CoV-2 infection is now being tested worldwide as a potential treatment for individuals who are seriously ill with COVID-19. Plasma is the fluid component of blood that transports the red and white blood cells, platelets, and other constituents such as dietary nutrients, proteins, minerals and salts, around the body. Trials of this convalescent plasma therapy (CPT) are under way to find out if the anti-SARS-CoV-2 antibodies in the donated plasma can help to speed recovery and prevent death in the worst-affected COVID-19 patients.
Although both vaccination and convalescent plasma therapy hinge on the pathogen-fighting roles of antibodies produced by the body’s immune system, the two approaches are very different. Whereas vaccines against SARS-CoV-2 are designed to trigger the pre-emptive production of antibodies and leave an entry to the body’s immune library in people who haven’t yet been infected with the virus, CPT is referred to as passive immunity. This treatment essentially gives seriously ill COVID-19 patients and those with poorly functioning immune systems ready-made ‘donor’ antibodies as a short-term solution to fighting existing COVID-19 infection. Scientists are developing a third antibody-based approach to treating COVID-19, which involves developing what are known as neutralizing antibodies that can directly stop the harmful virus from infecting a cell. Once neutralizing antibodies have been identified, they can be manufactured in the laboratory, and so don’t require blood donations.
Every year transfusions of whole blood save the lives of countless people who have experienced blood loss through trauma, or who have serious blood disorders. However, blood contains many specific components, including immune system cells, clotting factors and albumin, that can all be extracted from plasma using modern technologies, to treat many different diseases that would otherwise be fatal. Clotting factors are used to treat serious bleeding disorders, including haemophilia, while albumin is a protein that can be used to help treat people with burns, sepsis, liver disease or kidney disease. Human antibodies, or immunoglobulins, isolated from donated blood can be used to support people with compromised immune systems, as well as to help treat people with infectious diseases such as COVID-19.
The process of separating out the different components in blood, known as fractionation, is hugely complicated, and involves a series of precisely controlled physical and chemical stages. GEA is recognized as one of the world’s leading suppliers of process systems for every stage of blood plasma fractionation. Experts here at GEA harness decades of know-how in blood plasma fractionation technology and process engineering to tailor most of the biggest manufactures of blood plasma products.
Organizations rely on our technologies, process knowledge and engineering expertise to configure any scale of fractionation process, from small-scale production, right up to the biggest commercial-scale plant that could produce enough blood products to help address diseases at a global scale.
The basic process of blood fractionation starts with the extraction of red and white cells and blood platelets from whole blood using centrifugation. The plasma that remains after extraction of the cellular components is then deep frozen for two months, for safety reasons, and slowly thawed, before plasma from individual donations are pooled.
The separation of different fractions and proteins from plasma commonly employs a process what’s known as a cold fractionation. Large-scale fractionation is generally based on the Cohn process, which was developed by a scientist called (Edwin J. Cohn), during World War II. The process involves mixing the plasma with increasing concentrations of ethanol while lowering pH and temperature at –3 °C to –7 °C, which results in precipitated plasma products such as specific antibodies.
Designing an integrated blood plasma fractionation plant is complex and challenging, and reliant on the ability to precisely control key parameters including pH, ethanol content and temperature. “You have to align different process steps such as separation, adsorption, purification, precipitation, virus inactivation and chromatography in a precise and efficient manner,” explained Tatjana Krampitz, Head of Technology Management, GEA BioPharma. “Therefore, you have to consider mechanical as well as operational requirements to get high purification and concentration of human plasma products. In every intermediate process step followed by purification, different, life-saving blood plasma protein products can be extracted.”
Experts at GEA tailor individual machines, modules and whole, automated fractionation plant for every scale of blood plasma fractionation. Our know-how covers each stage, from mixing and centrifugation, to the design of process vessels, chromatography systems, automation and sterilization systems. GEA spray- and freeze-drying technologies, for example, help innovative technology companies to develop temperature-stable blood plasma products that have a long shelf-life and do not require refrigeration, so they can more easily be transported to hard-to-reach and remote areas.
We are proud to work with groundbreaking companies such as CSL Behring, which is part of the CoVIg-19 Plasma Alliance, a major industry collaboration that is working to develop CoVIg-19, a potential plasma-derived therapy for treating individuals with serious complications from COVID-19. Over the last 15 years we have partnered with CSL Behring to design and build plant for producing plasma-derived haemoglobin at multiple sites around the world.
GEA technologies play an integral role in helping scientists and industry to develop processes for manufacturing new generations of vaccines and antibody-based treatments against existing, and emerging diseases. We don’t just offer technologies for producing plasma products. Our expertise spans the design and supply of end-to-end systems for manufacturing vaccines at industrial scale, and for producing antibodies in the laboratory.
In these uncertain times, we are committed to supporting the global effort to fight coronavirus, or any other future epidemic. Guided by our pledge to develop "engineering for a better world," GEA is harnessing its decades of expertise to develop solutions that will help to bring new treatments to market in the shortest possible time.
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CPT for treating COVID-19
CPT for treating COVID-19 involves collecting blood plasma donated by patients who have been recovered from COVID-19 for at least two weeks. Their plasma contains a class of anti-SARS-CoV-2 antibodies known as immunoglobulin-G, or IgG. The donated blood is processed to ensure it is safe, and then fractionated, or split, into different components, so that the fraction containing the antibodies is isolated and purified. Convalescent plasma therapy isn’t a new concept. CPT was used to treat patients during the Spanish flu pandemic of 1918. Much more recently CPT was tested during outbreaks of two different coronavirus strains, including SARS coronavirus, which was identified in 2003, and middle Eastern respiratory syndrome (MERS), which was first reported in 2012.
