Anti-N in patients undergoing regular haemodialysis—A possible association with early transplant failure

Abstract

Anti-N is a relatively uncommon antibody. However, its occurrence in patients undergoing regular haemodialysis and its possible association with early transplant failure have been recognized. Small accumulations of red cells remain in the dialyser even after intensive flushing and it is postulated that these cells altered by the action of formaldehyde are inadvertently reinfused to the patient who may then develop the blood group antibody. In 1978, over a period of 8 mth, 72 patients on the haemodialysis programme at the Auckland Hospital were screened for the presence of red cell antibodies that were reactive at room temperature or above. Of these, 6 were detected to have Anti-N. During this period the patients had undergone renal dialysis up to 3 times per wk with reuse of the dialysers which were sterilized using 2% formaldehyde. Prior to transplantation all patients underwent compatibility testing against donor cells. Tissue typing and matching were performed by routine microlymphocyto-toxicity methods. Five of these patients subsequently underwent renal transplantation. In 4 patients the kidneys never functioned adequately. Histological studies done on the kidneys that failed to function showed thrombosis of renal vessels and cortical infarction. The clinical pattern seen in the patients and the above histological findings may be compatible with thrombosis of the renal vessels, due to anti-N reacting with the red cells in the cold kidney at the time of transplantation. It is not possible to be certain of the role of anti-N antibodies if any, in the failure of these transplants, but it is suggested that careful screening for the presence of anti-N is done in patients who have undergone chronic haemodialysis. A policy has now been adopted that in any patient with anti-N, kidneys to be transplanted are pre-warmed to approximately 20°C before the renal circulation is established.