Blood grouping using the genetic approach
At present, most blood used in transfusions is typed serologically. This means that blood is not phenotyped for some rare clinically significant antigens. The consequences are that some individuals with rare blood genotypes can become alloimmunised with problems of compatibility if future transfusions are needed. Life threatening situations may then arise, particularly for patients requiring multiple transfusions such as those suffering from sickle cell anaemia and haemophilia. The answer to this problem is DNA based genotyping. Unfortunately, it has not been economic or practical to genetically blood group every possible sample of blood for donation. The BLOODGEN consortium therefore investigated means of genotyping all clinically significant blood types. Molecular blood grouping experts across Europe joined forces to provide a platform for a series of high throughput blood genotyping tests. Project partners have constructed DNA chips or 'Bloodchips' based on DNA oligonucleotide microarrays. This approach was combined with the real-time fluorescent polymerase chain reaction (PCR) assay. Together, screening for the large number of blood group alleles while typing for those with rare low-level alleles was made possible. Pre-clinical trials were performed on patients throughout Europe with the aim of introducing molecular blood typing as a routine procedure. That way, safer, more reliable blood transfusion free of complication could be introduced. Information has been disseminated through scientific publications, conferences and workshops. A Bloodchip workshop was recently held at the University of West England in Bristol, UK. As well as detailed background to the technology, the course offered instruction and a hands-on approach to working with the genotyping DNA array. For those interested parties, the project website is http://www.bloodgen.com/