Pletelet Accumulation observed by Electron Microscopy in the Early Phase of Renal Allotransplant Rejection

Abstract

THE rejection of skin allografts depends on an immunological response of the recipient¹ which can be transferred with whole cells². The contribution of soluble antibody to rejection of solid tissue grafts remains an open question³. Although antibody may react directly with donor cells to produce a cytotoxic effect, other destructive mechanisms are equally possible. For example, Gardner, Guttman and Merrill⁴ have observed an ischaemic response during rejection of rat kidney transplants. Indeed, interference with the blood supply leading to cell destruction in grafts undergoing rejection has previously been deduced from metabolic studies^5,6. Such vascular blockades could be produced by platelet aggregates, as noted by Porter⁷ in acute rejection of human kidney transplants. The work reported here shows that substantial numbers of platelets accumulate in dog kidneys within minutes of renal transplantation to sensitized recipients. These platelets may be important contributors to the set of reactions responsible for allotransplant rejection^8,9.