View from the lab: It's enough to make your blood run cold
(Filed: 10/12/2003)
B Rhesus positive - it's enough to make your blood run cold writesProf Steve Jones
B-Plus; the story of my life, really, and - I learnt a few weeks ago - also that of my blood group. Yes, it's B Rhesus positive, the aristocratic mix borne by only about one Briton in 15. I made the discovery as part of a Radio 4 series in which the BBC, famed for its ability to squeeze blood out of stones, did the same to its presenter (to avoid the risk of product placement, the last episode went out yesterday). I should have started giving blood long ago. As a student I was turned down on the grounds of a streaming cold and never went back. Now I am on their books (and it's painless: call the National Blood Service on 0845 7711 711). Years ago, I applied for a job at one of those universities in which the staff are scruffier than the students. Unfortunately I got a B-Minus when I described my knowledge of biology as impressively broad, but remarkably shallow. Well, making this series showed it to be rather narrower and notably less deep than I thought. I turned up plenty of nonsense; one book recommends that we Bs should avoid rhubarb and most Japanese are convinced that people of that blood group are blessed with cheery and creative personalities (and, as you can tell, they are right). Below the froth there's an amazing amount of science. It started early. In 1666 Robert Boyle, of gas-law fame, wondered whether a mastiff's blood transfused into a bloodhound might reduce its ability to smell (and his friend Samuel Pepys speculated that if he moved blood from a Quaker to an archbishop the latter would change his beliefs). A year later a Frenchman, M Mauroy, was given calf's blood in the hope that an infusion of the animal's mild nature would calm down a "phrensy, occasioned by a disgrace he had receiv ad in some Amours" (syphilis, in other words). He died, of course, for his immune system recognised the cow's blood as foreign. Even a transfusion from a random Frenchman had a good chance of killing him, for those who give must match those who receive. There are nearly 30 separate blood group systems - some familiar, like ABO and Rhesus - and some less so; and, embarrassingly enough, we have no idea why they are there. Rhesus is the most baffling, for a marriage between a positive man and a negative woman may lead to the mother mounting an attack on her unborn child, with disastrous consequences. Surely evolution should do away with one variant or the other - but it has not. ABO is almost as hard to understand. Certainly, there are dozens of associations with disease, for people with O are better at resisting malaria but worse at cholera, while the As suffer more from cancer (and we Bs are allegedly more liable to diarrhoea) - but that scarcely explains why the variation is there in the first place. Doctors prefer 'how?' questions to 'why?' ones like those - and their attitude pays off. The battle against the groups is well advanced. Blood replacement is a hot topic. The search began with Sir Christopher Wren, who suggested that beer would work. It doesn't; but now we can separate the crucial oxygen-carrying molecule - haemoglobin - from the cells that hold it, and inject the naked protein straight into the patient. This avoids the immune problem. The method is quite effective and has real practical advantages. The product can be stored on the shelf for years and needs no matching. Although it does not last long in the body and can damage the kidneys as it is broken down, it is already widely used in South Africa (where there is a shortage of safe blood because of the Aids crisis). It may soon be licensed in America and in Britain. The most remarkable fact - with a nod to the memory of M Mauroy - is that the blood used comes not from men but from cows (and Jehovah's witnesses, who reject human blood, really like the idea). If that's a step too far, the Americans have made a completely synthetic replacement. It is related to the banned refrigerator fluid Freon (in which carbon atoms are replaced by fluorine) and soaks up lots of oxygen and releases it on demand. It has been tried on more than 1,000 patients in surgery, with some success. There are, though, certain difficulties. If I have a transfusion of O blood (accepted by everybody, whatever their own group) will I, as the Japanese believe, become more dependable - and is there a danger of turning bovine after a shot of haemoglobin or chilly with the artificial stuff? I rather hope I never need to find out. |
