Transfusion-specific alloimmune responses following blood transfusion pre–kidney transplantation

It is widely accepted that blood transfusions can cause allosensitization, but it is often reported that new human leukocyte antigen (HLA) antibodies are nonspecific and transient. This study explores the effect of blood transfusion on allosensitization in waitlisted transplant patients including the development of transfusion-specific antibodies (TSAs), both while they remain on the waiting list, and following subsequent transplantation. A total of 105 blood donors of transfusions received by 50 patients on the transplant waiting list were HLA typed. De novo HLA antibodies developed in 62% of patients following transfusion, with 34% of patients having at least 1 TSA. TSAs developed in 23% of patients with no circulating HLA antibodies at the time of transfusion and in 50% of patients with circulating HLA antibodies. This was associated with an average increase in calculated reaction frequency of 16.4%. Of the 34 patients who underwent transplantation, the majority received a kidney with at least 1 shared HLA specificity with a transfusion donor. After transplantation, 14.7% had a newly detected TSA within 3 months. These patients had higher rates of rejection, specifically antibody-mediated rejection, at 3 years. The use of HLA-selected blood for waitlisted patients, where transfusion is unavoidable, could therefore improve transplant outcomes.