HLA Mismatching Is an Independent Risk Factor for Worse Patient Survival Among Lung Transplant Recipients in the United States.

Abstract

Currently HLA donor/recipient mismatches are not considered in lung donor allocation or in risk adjustment models for assessing performance of transplant programs. We analyzed patient survival in lung transplant recipients by HLA mismatches (MM). Methods: Adult recipients reported to the Scientific Registry of Transplant Recipients (SRTR) database (01-11) were stratified by number of HLA-A,-B,-DR MM. Patient survival was assessed by Kaplan-Meier analysis. Cox proportional hazards regression determined predictors of patient survival. Multivariable analysis was conducted to assess the independent effect of MM adjusted for donor age, gender, race and cause of death, recipient primary diagnosis, use of ventilator, FVC, age, race, gender, primary diagnosis, size of transplant program and year of transplant. Results: The study includes 14,860 adult (18+) recipients, 56 % males, 86% Caucasian, 32% with OPD/Emphysema as primary diagnosis, median donor age 33 yrs and median recipient age 53 years. The proportion of 2-Ag MM was 51, 70, 54% at loci HLA-A, B, DR, respectively. The median follow up was 24 months (0-120) and the overall 5 year patient survival was 54%. Four percent of recipients had 0- 2/6 MM. Five-year patient survival among patients with 0-2 MM was 62% compared to 54% among patients with 3-6 MM (Figure 1).Figure: No Caption available.Higher MM was independently associated with diminished patient survival (AHR= 1.27, 95% CI. 1.07-1.51 p= 0.006). Among the 3 HLA loci, this effect was strongest and also independently associated with 2-HLA-DR MM (AHR= 1.17, 95% CI. 1.01-1.35, p= 0.03). Conclusion: HLA MM is an independent risk factor for poor patient survival after lung transplant. Although HLA matching may not be feasible for lung organ allocation, it could be important for risk stratification in individual patient clinical management. MM may also be an important consideration for more accurate evaluation of transplant center performance.