He donated plasma as often as he could – every two weeks for 60 years. Were it not for 13 units – 6.5 liters, or over a gallon and a half – of donated blood, James Harrison would have died. He wanted to pay it forward. Little did he know that he would more than make up for the donations that saved his life – by the time he retired from giving blood, he had saved nearly 2.5 million babies' lives. Harrison first started donating blood in 1954 – he signed up as soon as he turned 18. It was four years after he had been admitted to hospital for three months, so sick that he had ended up having a lung removed. “I was always looking forward to donating, right from the operation, because I don't know how many people it took to save my life,” he told NPR in 2015. “I never met them, didn't know them.” Ian Fleming may have had a golden eye; James Bond may have had a golden gun; but James Harrison had a golden arm. “Every bag of blood is precious, but James' blood is particularly extraordinary,” Jemma Falkenmire, of the Australian Red Cross Blood Donor Service, told CNN. “His blood is actually used to make a life-saving medication, given to moms whose blood is at risk of attacking their unborn babies.” What’s the reason for Harrison’s incredible lifesaving ability? It’s because his blood has is home to a huge number of rare antibodies known as Rh (D) immune globulin, or anti-D. If you’ve ever been pregnant – and especially so if you have a Rhesus negative blood type – that may ring a bell. There’s a disease called Rhesus D Hemolytic Disease of the Fetus and Newborn, or HDN, that can occur during pregnancy, and it’s extremely dangerous. It can cause severe spleen and liver problems, brain damage, and even death in the fetus. To understand what causes HDN, we have to explain how blood types work. Everyone has one of eight blood types, all defined by which antigens and antibodies are present or missing on their blood cells and plasma. There are the four main categories: A, B, AB, and O, and each of those can be split into either a Rhesus positive or a Rhesus negative version. Being “Rhesus positive” means your blood cells carry the RhD antigen, while Rhesus negative blood does not. For the most part, that will make little difference in your life – unless, say, you need a blood transfusion, at which point it becomes very important indeed. While Rhesus positive people can safely receive Rhesus negative blood, the same is not true in reverse – if a Rhesus negative body detects the RhD antigen, it will treat it as a foreign body and mount a defense against this intruder. Chief in the bloody arsenal is the anti-D antibody – existing just to prowl for RhD antigens, find them, and destroy them. Once a RhD negative person has been exposed to RhD positive blood, they will develop those antibodies and keep them forever. In pregnancy, this reaction, known as becoming “sensitized” to RhD antigens, can be devastating. When someone is pregnant, small amounts of fetal blood will inevitably mix with theirs – and if the fetus’s blood is RhD positive, and the pregnant person’s is negative, that same immune reaction is going to be triggered, causing HDN. “Historically, HDN was one of the major causes of infant mortality and lifelong severe disability in our population,” Robert Flower, transfusion scientist at the Australian Red Cross Blood Service, told the Sydney Morning Herald in 2017. “It was a terrible, terrible condition.” That changed in 1966, when scientists at the International Blood Transfusion Congress in Sydney made a stunning announcement: HDN could be prevented with an injection of anti-D – the very same antibody that was responsible for the condition. It sounded wild, and many major medical bodies refused to fund clinical trials into the idea – even the American National Institutes of Health called the idea “a nonsense.” But the scientists believed that by introducing a little bit of anti-D – not enough to attack the developing fetus, but just enough to get rid of any RhD positive blood cells that had made it into the pregnant person’s blood – they could stop the dangerous immune reaction from ever happening. Amazingly, it worked – and it still does: pregnant RhD negative people still receive anti-D shots today. Cases of HDN have gone from common, affecting around one in seven pregnancies in the US, to incredibly rare – in 2003, for example, that same statistic had been reduced to one in 370. This is where James Harrison comes in. Even today, the only place doctors can get those anti-D antibodies is from plasma donations – even then, it has to be plasma from RhD negative people who have, at some point, become sensitized to RhD antigens. Only they have the crucial anti-D antibody that specializes in hunting down and destroying the RhD antigens. Thanks to all those blood transfusions when he was a kid, possibly containing RhD antigens, Harrison has them by the bucketload. “Very few people have these antibodies in such strong concentrations,” Falkenmire told the Sydney Morning Herald. “His body produces a lot of them and when he donates his body produces more.” When Harrison learned about his miracle blood, he switched from donating whole blood to donating plasma only – and he turned up to donate as often as he could. Every two weeks over a period of 60 years, with a grand total of 1,172 donations upon his retirement aged 81 – the upper limit in Australia for donating. “Every batch of Anti-D that has ever been made in Australia has come from James’s blood,” said Falkenmire. “And more than 17 percent of women in Australia are at risk, so James has helped save a lot of lives.” With nearly 2.5 million babies alive because of his donations, Harrison has become – deservedly so – something of a hero in his homeland. He’s even been awarded the Medal of the Order of Australia, one of the country's most prestigious honors. But he’s more stoic about the whole thing. “Some people say, ‘Oh, you're a hero,’” he told NPR. “But I'm in a safe room, donating blood. They give me a cup of coffee and something to nibble on. And then I just go on my way. ... No problem, no hardship.” Source