James Harrison, Australia's most successful blood and plasma donor, died at 88, leaving behind a record of saving lives that will never be equaled. Nicknamed the "Man with the Golden Arm," Harrison's blood was rare in that it had a special antibody that was instrumental in creating life-saving medication for mothers and their unborn children. His incredible efforts saved more than 2.4 million babies, making him one of the most remarkable donors in medical history.Having been born in Australia, Harrison's blood donation experience started following a health crisis. At 14, he was subjected to open chest surgery and survived on the basis of blood transfusions. Extremely touched by the kindness of strangers, he promised to return the favor in the form of being a donor himself as soon as he could. True to his promise, at 18 he rolled up his sleeves for the first time, even though he had always been afraid of needles.What began as a gesture of appreciation quickly evolved into a lifelong endeavor. During a span of six decades, Harrison donated blood and plasma over 1,100 times before retiring in 2018 at the age of 81. His donations became the backbone of Australia's medical breakthroughs for the treatment of a rare yet life-threatening illness called Haemolytic Disease of the Fetus and Newborn (HDFN), also referred to as Rhesus disease.Discovery of a Rare AntibodyMedical researchers found in the mid-1960s that Harrison's blood held a rare and essential antibody called Anti-D. This antibody was instrumental in creating a revolutionary treatment to ward off HDFN, a disorder that happens when a mother's immune system strikes back at her unborn child's red blood cells because of incompatibility of blood types. If left alone, this disease might result in severe anemia, brain damage, or infant death.Scientists suspect that Harrison’s unique blood composition may have been a result of the transfusions he received during his surgery as a teenager. Regardless of its origins, his rare antibodies became a beacon of hope for thousands of expectant mothers and their babies.Harrison's unshakeable dedication rendered him Australia's inaugural and most committed Anti-D donor. As reported by the Australian Red Cross Lifeblood, nearly 17% of expectant mothers in the nation need Anti-D injections, and the majority of the supply is from a limited group of fewer than 200 plasma donors. Harrison's generosity formed the basis of this life-saving treatment, which continues to save nearly 45,000 infants annually.Even with the praise and global acclaim, Harrison was humble. In 1999, he received the Medal of the Order of Australia, among the country's most distinguished civilian awards, for his remarkable service. But he most often minimized his efforts, encouraging others to donate and carry on the life-saving work.Harrison's death on February 17 at Peninsula Village Nursing Home on the New South Wales Central Coast brought an era to a close, but his legacy lives on. Researchers at the Walter and Eliza Hall Institute of Medical Research (WEHI) in Melbourne, in partnership with Lifeblood, have been developing a project known as "James in a Jar." By using Harrison's blood and immune cell samples, scientists have been able to replicate and grow the Anti-D antibody in the laboratory. This development is promising that the vital treatment can be produced on a large scale without the need for human donors in the future.Tracey Mellowship, Harrison's daughter, remembers her father not only as a life-saver but also as a man with a big heart and a great sense of humor. His tale is a strong reminder of what one person's dedication to a cause can do to millions of lives.