What are some ways that potential recipients become sensitized?
- • Pregnancy
- • Exposure to antigens from previous transplants
- • Exposure to antigens from blood product exposure (e.g., transfusions)
Of note, it has not been shown that removal of leukocytes via leukodepletion (“washing” packed red blood cell units) reduces the risk of sensitization or development of HLA antibodies. The erythrocytes actually carry HLA Class I molecules and are in large enough quantity in a unit of packed red blood cells that they can stimulate a HLA Class I sensitization. Despite this evidence, leukodepletion occurs in almost 100% of centers in Europe and 75% of centers in the United States.
