Sharing Cells

There are few things that all human beings share – but blood is one of them. Everyone has it and without it we die. But what is it? What does it do? And why is it the basis of a global industry?

First some facts. The average adult body contains around five liters of blood, which accounts for around eight per cent of body weight. Whole blood is a suspension of cells in a liquid called blood plasma. Plasma accounts for 55 per cent of the volume of blood and is itself 91 per cent water, in which are dissolved various proteins and a whole host of essential trace elements from hormones and neurotransmitters to amino acids and vitamins. Plasma circulates nutrients around the body and removes waste products such as carbon dioxide.

The other 45 per cent of blood volume consists overwhelmingly of red blood cells, together with a small proportion of white blood cells and platelets. These are all produced in the body’s bone marrow. Red blood cells, which give human blood its color, distribute oxygen and nutrients around the body. White blood cells are part of the immune system and platelets are responsible for blood clotting.

Transfusion

Blood keeps people alive: and even before the development of scientific medicine, doctors knew that it was vital. The practice of bloodletting – deliberately cutting the patient to allow a quantity of blood to flow out – was one of the commonest medical procedures from the ancient world to the 19th century and was used to treat virtually any disease.

The first successful transfusion of human blood was carried out by a British obstetrician in 1818, but the door to safe transfusion was only opened in 1901 when the Austrian Karl Landsteiner discovered human blood groups. Until that point the possibility of incompatibility was not understood.

While blood can keep people alive, incompatible – or worse, contaminated – blood can kill.

Transfusion techniques using blood that had previously been donated, cooled and stored, were pioneered during World War I, and the first national system of blood banks was established in the Soviet Union in the 1930s.

Today, worldwide, donors give around 45 million liters of blood a year, which is used for a wide variety of purposes. In affluent countries, it is most commonly used to support invasive medical procedures and operations like open-heart surgery and organ transplantation. In low and middle-income countries it is used more often in pregnancy-related complications and severe childhood anemia.

However, it is now relatively uncommon for patients to be given transfusions of wholeblood, as separating the blood into its various components allows a single donation to benefit several patients. People are given the blood component they most need – be it red blood cells, platelets, plasma or more specialist blood products. These include life-saving coagulants used in the treatment of hemophilia and various liver diseases, and products that can control bleeding during operations.

Specialized process

Processing blood into its various components is a highly specialized process – in part due to the inherent variability of the source material, and because of the need for a high degree of product purity.

Filtration is used to separate the white blood cells and platelets. The remaining red blood cells and plasma are then separated in special centrifuges. Separation of the proteins from plasma normally uses a cold fractionation process developed during World War II. It involves mixing the plasma with increasing concentrations of ethanol at -3 to -6°C. Different plasma proteins are precipitated out of the solution at different concentrations and temperatures. While the concentrations of some of these proteins such as albumin are relatively high (about 40g/liter) others are only available in miniscule amounts – down to a few nanograms/ml for some coagulation factors.

Demands on the equipment used in the manufacture of these specialist products are immense. As well as needing to be an aseptic process, the fractionation requires the exact cooling of the separation vessel at various stages, an extremely high dry matter content of the solids and precise control systems.

There are few companies in the world that can meet these demands. GEA is one of them.

GEA and blood

The processing of blood must meet highest requirements to ensure clinical excellence. GEA Process Engineering company GEA Diessel is a specialist in this field using its experience and expertise to unite vital GEA technologies to create complete processing plants for blood and plasma processing: centrifugation, nano-filtration, chromatography and precise temperature control. The company has successfully planned and built plants for plasma fractionation in Germany, Switzerland and China.

Depending on the application, plasma needs to be frozen to -30°C within 60 minutes. GEA Heat Exchangers provides variants of GEA Küba’s SG air coolers which can accurately maintain such extreme low temperatures.

GEA Westfalia Separator Group, part of GEA Mechanical Equipment, is at the forefront of developments in processing blood plasma. Thanks to a unique design feature the Westfalia Separator® hycon now allows the discharge process to be fully automatic. This saves time and makes the process safer for the product and operator. The suitability of the separator for CIP and SIP processes guarantees sterile handling of the blood plasma protein during the entire fractionation process. All hycon components coming into contact with the product can be cooled – essential for human blood plasma fractionation. Also production can be carried out at room temperature, rather than the entire production area being at -5°C.