After the first few donations, it was discovered that his blood contained unusually strong and persistent antibodies against the D Rh group antigen.
Blood which contains a high level of anti-D antibodies can be processed to create immunoglobulin-based products used to prevent haemolytic disease of the newborn (HDN).
This antigen sensitization and subsequent incompatibility phenomenon causes Rhesus disease, the most common form of HDN.
[5] Through their donations, the members of NSW's Rh Program have provided millions of doses of anti-D and helped prevent thousands of deaths and stillbirths, as well as many more instances of sickness and disability caused by HDN.
Over his lifetime, Harrison's donations amounted to tens of thousands of doses worth of antibodies and had contributed to every batch of anti-D produced in NSW.