Hi, Thanks for writing in. To favor a transplant acceptance, the donor and recipient ate matched. One of the tests she will have before a transplant is HLA typing, also called tissue typing. This test identifies certain proteins in the blood called antigens. Antigens are markers on the cells in your body, which help your body, tell the difference between self and non-self. This allows the body to protect itself by recognizing and attacking something that does not belong to it such as bacteria or viruses. Antibodies are formed in response to antigens. If antigens are matched then the antibodies will not interfere.