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protein interaction networks. A set of three TFs were selected through a combinatorial cell culture approach that was shown to promote growth of CD41- positive megakaryocyte precursor cells. In the presence of thrombopoietin, these cells were shown to mature into CD41- positive, CD42-positive and GPVI-positive mature MKs that also expressed TFs crucial to the final stages of maturation and proplatelet formation. Crucially, the culture method allows the production of mature MKs from iPSCs in less than 20 days and with a cell number amplification compatible with preclinical studies in vivo. Using a forward programming approach, it has been possible to identify a set of three TFs that promotes the growth of megakaryocyte precursors from human iPSCs, which, in turn, can be grown into mature MKs under chemically defined, GMP-compatible conditions. The number of cells produced permits in vivo testing and translation into a three-dimensional culture system for large-scale production.


Transfusion support, as part of damage control resuscitation (DCR), is now closely integrated with all other aspects of resuscitation, including haemorrhage control and surgery.


service. However, the remaining 42 antigens are encountered quite rarely. This is due to them either being high-prevalence antigens, and thus antigen-negative individuals are encountered rarely, or low-prevalence antigens in which the opposite is true. Either way, they are not considered much of a transfusion problem although antibodies to low-prevalence MNS antigens have occasionally caused haemolytic disease of the fetus and newborn.


Good blood in bad places Massive haemorrhage is the most immediate threat to the injured service person. The mortality rate after massive haemorrhage in trauma is high unless actively managed. Transfusion support, as part of damage control resuscitation (DCR), is now closely integrated with all other aspects of resuscitation, including haemorrhage control and surgery. DCR and the requirement for an associated ‘massive transfusion capability’ presents enormous challenges both to deployed clinical laboratory services and to the supporting blood services. However, during the past decade, both have evolved successfully to deliver transfusion support for combat care. All this has been done against a background of increasing public expectation, professional standards, and regulatory frameworks. Transfusion support is now delivered throughout the patient pathway, from the place of injury through to definitive surgery, and the presentation described some of the recent developments used to deliver transfusion support to intra-hospital and pre- hospital care.


Update on the MNS blood group system The 46 antigens of the MNS blood group system are carried on the erythrocyte proteins glycophorin A and glycophorin B. While the function of these proteins is not completely understood, the diversity encoded by the GYPA gene family is fascinating and has provided an excellent model for studying human genes. In transfusion medicine, we are familiar with the antigen pairs M and N, S and s, and antibodies to these antigens are quite commonly encountered in the hospital transfusion


DECEMBER 2013


Use of microarrays in transfusion and transplantation Multiplex assays may address the need for a larger spectrum of testing markers in blood grouping, pathogen testing, tissue antigen determination and other transfusion- and transplantation-related applications, if proven feasible and cost-effective. Microarrays were developed for a highly multiplexed analysis of gene expression, but a number of diagnostic applications have been developed since. In certain situations the DNA or protein microarray is the single analytical tool, while in other applications, such as blood group genotyping, it is used in combination with a nucleic acid amplification technique, such as the polymerase chain reaction (PCR). An example of successful routine use of a microparticle-based microarray system is HLA typing by Luminex. It combines PCR amplification with group-specific primers for MHC I and II and the amplicon resolution with bead-immobilised specific oligonucleotide probes. In addition, bead–immobilised HLA antigens can be used to determine the HLA antibody status. Other microarray techniques are still in development for potential future diagnostics. Virochip is a microarray platform containing a large number of oligonucleotide probes, allowing simultaneous identification of viral pathogens. Protein microarrays are used for antigen and antibody analysis. Microarrays are also an integral part of some next- generation sequencing (NGS) protocols, facilitating, for example, target template enrichment. This leads to amplification of the desired subset of target sequences, limiting the large amount of data generated by NGS.


Root cause analysis In the UK, hospitals have been reporting blood transfusion incidents to a UK national haemoviligance scheme (Serious Hazards of Transfusion [SHOT] scheme) since 1996. During this time, the SHOT team has analysed over 6000 events caused by error, and more than 3000 transfusion reactions. It is clear from the data that errors in the hospital environment occur throughout the transfusion chain and that all the events caused by error are avoidable. When errors occur in the healthcare environment, the response is often an attempt to identify an individual or individuals who must


carry the blame. To err is human, but human error is not the only factor involved in patient safety incidents. With the exception of those incidents where there is evidence of gross negligence, recklessness or criminal behaviour, in the great majority of cases the root causes of serious failures stretch far beyond the actions of the individuals immediately involved. Understanding why errors occur is vital to understanding how to identify and understand their potential causes. Having a robust system for reporting and investigating transfusion incidents, identifying the causes and putting in place appropriate corrective action helps to prevent similar incidents from occurring in the future.


Roles and responsibilities in transfusion


The blood transfusion laboratory has been seen as an exclusive domain of biomedical scientists; however, changes in automation and IT with associated skill-mix changes in other associated disciplines is causing a rearrangement of who does what. It is not just a move of tasks to support workers but also a move in which biomedical scientists are taking on roles and responsibilities previously the domain of medical colleagues. During this time of change, it is important that roles and responsibilities be carefully planned with appropriate knowledge and skills acquired to ensure safe delivery of services. The presentation looked at what changes might be made, under what circumstances, with the appropriate knowledge and skills to enable this to be done safely.


Selected summaries from the Congress cellular pathology and cytopathology programmes are scheduled to appear in next month’s issue. Summaries from the medical microbiology and virology programmes were published in the October issue (page 586) and from the clinical chemistry and immunology programmes in the November issue (page 650).


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THE BIOMEDICAL SCIENTIST


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NHSBT


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