Relative impact of human leukocyte antigen mismatching and graft ischemic time after lung transplantation

International audienceBackground: Recent data strongly suggest that human leukocyte antigen (HLA) mismatching has a negative impact on development of bronchiolitis obliterans syndrome (BOS) and survival after lung transplantation (LTx). Because HLA matching is sometimes achieved by extending ischemic time in other sotid-organ transplantation models and ischemic time is a risk factor per se for death after LTx, we sought to compare the theoretical benefit of HLA matching with the negative impact of lengthened ischemic time. Methods: In this collaborative study we compared the relative impact of HLA mismatching and ischemic time on BOS and survival in 182 LTx recipients. Results: Using multivariate analyses, we observed a lower incidence of BOS (hazard ratio [HR] = 1.70, 95% confidence interval [CI]: 1.1 to 2.7, p = 0.03) and enhanced survival (HR = 1.91, 95% CI: 1.24 to 2.92, p = 0.01) in patients with zero or one HLA-A mismatch compared with those having two HLA-A mismatches. This beneficial effect on survival was equivalent to a reduction of ischemic time of 168 minutes. Conclusions: We observed a reduced incidence of BOS and a better survival rate in patients well-matched at the HLA-A locus, associated with an opposite effect of an enhanced ischemic time. This suggests that graft ischemic time should be taken into account in future studies of prospective HLA matching in LTx