Evolution of blood transfusion medicineEvolution of blood transfusion medicine

Every two seconds someone needs a blood transfusion or blood product, such as people of all ages who are injured, need surgery or who are suffering from illness. Around 117.4 million blood donations were collected globally during 2018; 42 per cent of these are collected in high-income countries, home to 16 per cent of the world’s population.

Blood transfusion saves lives and improves health, but many patients requiring transfusion do not have timely access to safe blood. Providing safe and adequate blood should be an integral part of every country’s national healthcare policy and infrastructure.

WHO recommends that all activities related to blood collection, testing, processing, storage and distribution be coordinated at the national level through effective organisation and integrated blood supply networks. The national blood system should be governed by national blood policy and legislative framework to promote uniform implementation of standards and consistency in the quality and safety of blood and blood products.

An adequate and reliable supply of safe blood can be assured by a stable base of regular, voluntary, unpaid blood donors. These donors are also the safest group of donors as the prevalence of blood borne infections is lowest among this group.

Despite ongoing improvements in the collection, processing, testing, delivery, and monitoring of transfusions during the past several decades, concerns over the safety of these therapies and the process in general continue today.

Blood transfusion in the 21st century is about safe blood, high quality and standardisations. The need for safe and quality blood and blood products is a worldwide issue and cannot be over emphasised. Blood saves lives but can also be life-threatening. Historically, viral infections e.g. HIV, HCV, and HBV, parasitic infections e.g. malaria have been transmitted via transfusion. A heartbreaking example in history was the 1980’s and 1990’s when many patients with haemophilia in the UK, France, Canada, Japan, U.S., and elsewhere contracted HCV and HIV from blood transfusions and factor concentrates.

Historically, there was concern about transmitting infectious diseases from a donor to a recipient. Now blood is regularly tested for infectious disease transmission, particularly for viruses such as Hepatitis B and C, HIV, and West Nile Virus. Traditionally, serum has been tested to look for the body’s response to past infectious exposure, but many serum tests have been replaced by molecular testing called nucleic acid amplification testing (NAT), which finds active viruses in the donor’s blood to determine infection risk. If an active virus is found, the donor unit is discarded. Blood transfusion has never been safer from known infectious risk than it is today.

There is, hence, an idealistic expectation that blood supply must be safe whatever the cost. The safety, quality and cost effective practices in transfusion of blood and components in which different professional groups with different functions are involved has to be ensured. Blood organisations and hospital transfusion services are therefore under pressure to minimise adverse events and the risk of transfusion transmitted infections. It seems unrealistic because of the emergence of new pathogens, e.g. variant Creutzfeldt-Jakob disease (vCJD), whose mode of transmission are not fully elucidated. Besides infection with microorganisms, transfusion also carries other hazards that can cause substantial morbidity without proper management systems.

Minimising risks

Today, the blood transfusion community continues to advance its transfusion systems, guided by the ISBT (International Society of Blood Transfusion), AABB (American Association of Blood Banks), FDA (Food and Drug Administration), and other federal and professional organisations. Researchers are also establishing new surveillance systems that record data and transfusion outcomes (haemovigilance system) to better understand and manage the risks associated with transfusion. They are offering more personalised treatment, limiting transfusions based on careful assessment of need, and ultimately improving patient care.

In addition to infectious disease risks, treating physicians must also manage other risks, such as post-transfusion reactions. These include transfusion-related lung injury (TRALI), during which the donor’s immune antibodies cause breathing problems in the recipient; transfusion associated cardiac overload (TACO), which is swelling caused by the increased blood volume; and post-transfusion iron overload, which is a build-up of iron in the body, usually caused by multiple or regular transfusions.

To minimise these risks, researchers studying the body’s immune response to transfusions have found that modifying the blood prior to transfusion can reduce reactions. In particular, removing white blood cells or radiating blood to prevent white blood cell growth can reduce the likelihood that the recipient will reject the donor blood. Recently, studies found that using male plasma and platelets may eliminate the transmission of certain antibodies that can cause reactions and are found only in previously pregnant women and transfused males. However, using these techniques has reduced the amount of blood available for transfusions, so researchers are working to identify better ways to safely increase available blood sources.

Avoidable transfusion errors, mostly in patient identification, remain a serious cause of injury and death. There is also heightened awareness of the risk of transmission of viral and bacterial infections. Of particular concern is the (theoretical) possibility of transmission of vCJD.

Unnecessary transfusions and unsafe transfusion practices expose patients to the risk of serious adverse transfusion reactions and transfusion-transmissible infections. Unnecessary transfusions also reduce the availability of blood products for patients who are in need.

Research and development

In recent years, the demand for red blood cells has declined, primarily because doctors are learning to transfuse more scientifically and use blood only when necessary. However, challenges remain. Type O negative red cells, which can be transfused to people of all blood types, is the blood type most likely to be in short supply, and there is a need for donors of all blood types, all the time.

Patient Blood Management (PBM) is an evidence-based bundle of care to optimise medical and surgical patient outcomes by clinically managing and preserving a patient’s blood. PBM has identified risk factors and modify them into the application of the “three pillars” of Patient Blood Management: optimise erythropoiesis (including red cell mass and iron stores), minimise blood loss (surgical) and bleeding (coagulopathy), harness and optimise the patient-specific physiological reserve of anaemia while treatment is initiated. While the phases in surgical and medical patients includes before specific treatment (Pre-operative), during specific treatment (Intra-operative) and following up after specific treatment (Post-operative).

Blood banks all over the world are excited about many developments in blood transfusion medicine that is under research and development. This includes a new red blood cell testing technology aimed at patients with illnesses that require frequent transfusions, for example sickle cell anaemia. These patients sometimes develop antibodies that complicate finding compatible blood for transfusion. A new FDA laboratory is evaluating this new technology, which identifies the genetic characteristics of a patient’s red blood cells so they can be more precisely matched to a donor.

Exciting research is also progressing on technologies that will significantly reduce any bacteria, viruses and parasites that may be in blood. These technologies would complement existing tests for these infectious agents, thus making a safe blood supply even safer.

There is also the topic of artificial blood. Companies are working to develop oxygen carriers that could substitute for red blood cells. We’re working forward and remain hopeful that one or more of these technologies eventually will prove to be safe and effective.

While the blood bankers continue to improve processes, the last decade has also seen developments in innovative approaches, particularly in high-tech cellular therapies and bioengineering.

New techniques can isolate specialised cell populations from blood – most importantly, hematopoietic progenitor cells (HPCs) that are used for stem cell transplantation. Because HPCs are easier to extract and the process is safer for donors, HPC transplantation has replaced bone marrow transplantation for many cancers and other diseases.