To the Editor: We read with interest the paper by Spector et al. (N Engl J Med 295:1217, 1976) on perfusion-related injury in transplanted kidney. Our experience is parallel to theirs in most regards, but differs in several important respects. We have found an excellent correlation between increasing deposition of fibrin in the glomeruli and decreasing graft survival (Hill GS, Light JA, Perloff LJ: Perfusion-related injury in renal transplantation. Surgery 79: 440–447, 1976) — a point that Spector and his colleagues do not specifically address. We have also been able to demonstrate, by electron microscopy of pre-implantation biopsies, that.