LAUSR

The increased feasibility for producing genetically engineered (GE) or‐ ganisms has allowed the field of xenotransplantation to take significant bounds forward in preclinical research and has aided understanding of both the successes and the failures of transplanted xenografts. As we move closer and closer to the International Xenotransplant Association 2019 Congress in Munich, Germany, the articles in this review highlight some of the key themes of xenotransplantation research. This includes seeking an increased understanding of the complex molecular mech‐ anisms surrounding xenograft rejection, development of the optimal GE xenograft model, and the reduction of clinical barriers within xe‐ notransplantation by evaluating outcomes of xenotransplantation in clinical practice and retrospective evaluation of xenograft failures. In the previous issue of Xenotransplantation, Zhou et al1 pro‐ vided an updated review of the complement system in xenograft rejection; Hundrieser et al2 discuss how porcine and human MHC‐II polymorphisms influence donor reactivity; Ladowski et al3 seek to eliminate all donor xenoantigens; Cooper et al4 review a 9 gene al‐ teration of porcine donors for clinical xenotransplantation; Zhou et al5 present a strategy to monitor xenograft rejection with porcine cDNA biomarkers; Zafar et al6 provide further research into reduc‐ ing porcine islet immunoreactivity; Li et al7 studied the cold storage of porcine hepatocyte spheroids; Iizuka et al8 deep dive into porcine C‐peptide pharmacokinetics; and, finally, Zheng et al,9 Zhao et al,10 and Yoon et al11 provide updates in corneal xenotransplantation.