One of the world’s most prolific blood donors – whose plasma has saved the lives of more than two million babies – has died.

James Harrison died in his sleep at a nursing home in New South Wales, Australia, his family said on Monday. He was 88.

Known as Australia’s “man with a golden arm,” Harrison’s blood contained a rare antibody called anti-D, which is used to make a drug given to pregnant mothers at risk of attacking their unborn babies.

Paying tribute to Harrison, the Australian Red Cross Blood Service said he pledged to become a donor after receiving a blood transfusion while undergoing major chest surgery at the age of 14.

He began donating his blood plasma at age 18 and continued to do so every two weeks until he was 81.

In 2005, he held the world record for the most plasma donations — a position he held until he was surpassed by a man in the United States in 2022.

Harrison’s daughter, Tracy Meloship, said her father was “very proud of saving so many lives without any cost or pain.”

“He always said it wouldn’t hurt, and the life you save could be your own,” she said.

Both Meloship and Harrison’s grandchildren also receive anti-D immunizations.

“[James] was thrilled to hear about families like ours who were saved by his kindness,” she said.

The anti-D vaccine protects unborn babies from a potentially fatal blood disorder called hemolytic disease of the fetus and newborn, or HDFN.

This condition occurs during pregnancy when a mother’s red blood cells are incompatible with her growing baby’s red blood cells.

The mother’s immune system then sees the baby’s blood cells as a threat and makes antibodies to attack them. This can seriously harm the baby, causing severe anemia, heart failure, or even death.

Before anti-D interventions were developed in the mid-1960s, one in two babies with HDFN died.

It’s not clear how Harrison’s blood became so rich in anti-D, but some reports suggest it was linked to a massive blood transfusion he received when he was 14.

There are fewer than 200 anti-D donors in Australia, but they help an estimated 200 mothers and their babies each year, according to the Australian Red Cross Blood Service, also known as LifeBlood.

LifeBlood is working with the Walter and Eliza Hall Institute of Medical Research in Australia to grow anti-D antibodies in the laboratory by reconstituting blood and immune cells from Harrison and other donors.

Researchers hope that lab-made anti-D antibodies could one day be used to help pregnant women around the world.

“Creating a new treatment has long been a ‘holy grail’,” said David Irwin, LifeBlood’s director of research.

He noted the shortage of donors committed to regular donations who are capable of producing antibodies of sufficient quality and quantity.