Platelet transfusion in an infant leading to formation of anti-D: implications for immunoprophylaxis

The immature infant immune system rarely makes RBC alloantibodies; however, most studies confirming the absence of alloantibodies in infants have involved transfusions that were matched for one of the most immunogenic antigens, rhesus D. The potential for D- infants to develop anti-D is unknown. Specifically, this issue has not been analyzed for infants receiving whole-blood-derived PLTs from D+ donors. The importance of understanding such risk is underscored by the fact that anti-D formation can be prevented by the administration of Rh immunoglobulin.

A D- infant with congenital heart disease received two D-mismatched whole-blood-derived PLT units at 17 weeks of age. He did not receive Rh immunoglobulin prophylaxis. Upon a subsequent admission 13 months later, anti-D was identified in his plasma sample.

The case presented here demonstrates that a young infant can respond to less than 0.6 mL of D+ RBCs and documents the youngest patient to have developed a RBC alloantibody from a PLT transfusion. To prevent anti-D formation, we recommend administering Rh immunoglobulin to all D- pediatric patients that receive PLT transfusions from D+ donors [correction].