Unlike the US-LAS, the Eurotransplant-LAS is Not a Risk Factor for De-Novo Donor Specific Antibodies.

De novo donor-specific antibodies (dnDSA) against class I or II human leukocyte antigens have been reported to occur in 13-61% of recipients after lung transplantation (LTx), and dnDSA have a significant impact long-term outcomes. In recent studies, the US-lung allocation score (LAS) at the time of transplantation has been found to be an independent risk factor for the development of post-transplant DSA. However, data on which of the many different LAS variables is responsible for the increase in the risk for dnDSA is lacking. In addition, these previous findings were solely based on the US LAS system, while a potential association with the Eurotransplant (ET) LAS has not yet been investigated. We analyzed patients who received primary LTx between January 2013 and December 2020 at the Medical University of Vienna. Re-transplantations, combined organ transplantations and patients without LAS were excluded. DnDSA with MFI values <1000 were defined as positive. In case of pre-transplant DSA, dnDSA were considered positive if MFI increased by >30% or >500. Patients who developed dnDSA (Group 'dnDSA') were compared to those the remaining cohort (Group 'controls'). Values and calculation parameters of the last LAS at the time of transplantation were analyzed. In addition, demographics and outcome factors were also compared. Of the 650 patients included in this study, 217 (33.3%) developed dnDSA. 59/217 (27.2%) already had pre-transplant DSA. Median LAS values were equal in both groups (36.3 vs 36.1; p=0.629). A high LAS status (values >50) was found less frequently in patients who developed dnDSA (n=36; 16.6%) compared to those who did not (n=69; 19.0%; p=0.473). Distributions of LAS factors such as diagnosis group (p=0.121), supplemental oxygen requirement (p=0.170), assisted ventilation (p=0.500), ECLS status (p=0.067), number of exacerbations (p=0.985) and renal replacement therapy (p=0.498), as well as sPAP (p=0.191), FEV1% of predicted (p=0.259) and FVC% of predicted (p=0.999) were similar between groups. Long-term graft survival was significantly impaired in the dnDSA group compared to controls (5 years: 61.6% vs 74.8%, p=0.025). DnDSA were associated with impaired long-term survival. However, in contrast to previous studies based on the US-LAS, in our cohort of ET-LAS patients, LAS was not associated with increased incidence of dnDSA. [ABSTRACT FROM AUTHOR]