Prospective Study of Recipient Human Leukocyte Antigen (HLA) Alloimmunization Following the Use of Cold-Stored Saphenous Vein Allografts in Vascular Surgery

<b>Objectives:</b> The aim of this study was to assess the HLA alloreactivity of cold-stored saphenous vein allografts (CSVAs) by identifying the production of HLA donor-specific antibodies (DSAs) in the recipient. The secondary objective was to evaluate CSVA rejection-related complications, such as CSVA thrombosis and/or aneurysmal degeneration in the recipient. <b>Methods:</b> This was a single-center, prospective, experimental before-and-after study which included participants undergoing CSVA placement, either to create a vascular access (VA) for hemodialysis or to create a lower limb arterial bypass. On Day 1, before CSVA placement, total blood samples were taken for HLA typing by sequence-specific primers (SSPs) and anti-HLA antibody detection using a Luminex assay. One month after CSVA placement, a second blood sample was taken to assess the appearance of donor-specific antibodies or an increase in the level of anti-HLA antibodies. Patency of the CSVA and potential aneurysmal degeneration were evaluated at 3 and 6 months with a Doppler ultrasound checkup. <b>Results</b>: From September 2022 to November 2023, 45 patients were included (30 men, 67%; mean age: 71 ± 12 years). One month after CSVA placement, no appearance of de novo anti-HLA antibody was detected in anti-HLA antibody-negative patients at inclusion (<i>n</i> = 28). Among the patients who already had anti-HLA antibodies at inclusion (<i>n</i> = 17), no increase in anti-HLA antibody levels or appearance of de novo anti-HLA antibodies was detected. <b>Conclusions:</b> This prospective study evaluating the immunogenicity of CSVAs through the appearance of anti-HLA antibodies one month after placement demonstrates that they do not seem to induce any HLA alloreactivity. Therefore, they may be used without the risk of HLA immunization in patients awaiting organ transplantation.