Blood cyclosporin concentrations and renal allograft dysfunction

• Published in: British Medical Journal (Clinical research ed.) Vol. 293; no. 6554; pp. 1057 - 1059
• Main Authors: Holt, D W, Marsden, J T, Johnston, A, Bewick, M, Taube, D H
• Format: Journal Article
• Language: English
• Published: England British Medical Journal Publishing Group 25.10.1986; British Medical Association; BMJ Publishing Group LTD
• Subjects: Adult; Aged; Biopsies; Blood; Cyclosporins; Cyclosporins - adverse effects; Cyclosporins - blood; Dosage; Female; Graft Rejection; Histology; Homologous transplantation; Humans; Kidney - drug effects; Kidney Diseases - chemically induced; Kidney Transplantation; Male; Middle Aged; Nephrotoxicity; Radioimmunoassay; Transplantation
• ISSN: 0267-0623; 1468-5833
• DOI: 10.1136/bmj.293.6554.1057

Forty nine renal allograft recipients taking oral cyclosporin suffered 76 episodes of renal dysfunction within six months of transplantation. These episodes were diagnosed as graft rejection or cyclosporin induced nephrotoxicity on the basis of histological findings in allograft biopsy specimens and the response to treatment. Mean predose blood cyclosporin concentrations measured by radioimmunoassay during the week before the onset of renal dysfunction were significantly higher when the cause was cyclosporin toxicity rather than graft rejection (392 v 741 nmol/l (471 v 891 ng/ml). During this period there was a significant association between both the frequency of measurements above 666 nmol/l (800 ng/ml) and the diagnosis of toxicity and the frequency of measurements below 333 nmol/l (400 ng/ml) and the diagnosis of allograft rejection. Cyclosporin measurements made at the time of biopsy and reference to the highest or lowest concentrations measured during the week preceding biopsy were of less value in distinguishing between the two groups. Despite lacking specificity for the parent compound, the radioimmunoassay used produced results which were of clinical value in optimising cyclosporin treatment.