Anti–Human Leukocyte Antigen Antibodies Are Present in Blood of Blood Donors: Is Therapy With Blood Preparations Safe for Graft Recipients?

Abstract Background Blood products infusions are often administrated to graft recipients. Post-transfusion reactions of anti–human leukocyte antigen antibodies (anti-HLA) are responsible for transfusion-related acute lung injury, but cases of graft rejection after blood product infusions were recently also proven. Methods The aim of this study was to assess, with the use of the very sensitive Luminex technology and traditional lymphocytotoxic test, the prevalence and cytotoxic activity of anti-HLA in blood donors with different medical histories to evaluate a potential risk of post-transfusion immune complications. Data were analyzed according to different normalized background cutoffs (1.5, 2.2; and the high cutoffs—10.8 for I class and 6.9 for II class anti-HLA). Results We observed that anti-HLA may be present in 36% of donors, and even in up to 73.6% of risk groups. Significant risk factors included female sex (23.9% to 64.2% for different cutoffs) and pregnancy history (30% to 72.5%), regardless of the cutoff used in analysis, whereas sera from female donors showed lower cytotoxicity (panel reactive antibodies). Anti-HLA were also detected in men (3.7% to 37%), in donors after a transfusion (0% to 62.5%), and even with no known risk factors (3.8% to 26.9%). Conclusions Luminex technology is a sensitive tool in anti-HLA detection, but consensus in measurement interpretation for blood donors is needed. Selection of blood products on the basis of medical history can be a useful alternative for routine testing of blood donors. The clinical significance of treatment of graft recipients with blood products requires further study; until then, more attention should be paid to possible complications.