Rhesus D (RhD) is a blood group antigen found on some human red blood cells (RBCs). When an RhD negative (RhDneg) mother is carrying an RhD positive (RhDpos) baby, the foetus’ RBCs can enter the mother’s circulation and induce an immune response against the RhD molecule. This anti-RhD antibody response increases with each pregnancy and can damage the baby's RBCs, causing Haemolytic Disease of the Newborn (HDN). HDN is a leading cause of miscarriage, stillbirth, and neonatal complications, impacting families and communities globally. Remarkably, administration of anti-RhD serum to RhDneg pregnant women has proved successful in preventing HDN in those countries where it has been adopted, reducing perinatal mortality by over 98%.
However, in lower-income countries, limited healthcare resources hinder effective anti-RhD prophylaxis. Developed nations also face challenges maintaining donor pools for anti-RhD serum, which requires repeated immunisations of RhDneg donors using foreign RBCs and is both costly and time consuming. The challenge of sustaining a voluntary donor pool was particularly evident during the COVID pandemic. For these reasons, it would be preferable to have access to a donor independent source of therapeutic anti-RhD antibodies.
In collaboration with Australian Red Cross Lifeblood and their donors in the Australian anti-RhD program, we have isolated a pool of anti-RhD mAbs monoclonal antibodies and we are now evaluating their functional activities against RhDpos RBCs in vitro. Our goal is to produce a standardised human monoclonal antibody formulation with quantifiable functional activity that can be produced at scale and made available globally.