Estimation of individual sensitivity to cyclosporin in children awaiting renal transplantation.
BACKGROUND
Optimal immunosuppressive drug therapy requires that efficacy be balanced against toxicity. We have performed in vitro assays of cyclosporin (CsA) efficacy in children awaiting renal transplantation.


METHODS
Peripheral blood mononuclear cells (PBMC) from 13 children awaiting renal transplantation and 10 healthy paediatric controls ("responders") were incubated in the presence of CsA (0-250 ng/ml). Irradiated PBMC from a parent (prospective live donor) were cultured with those of the child in the presence of interleukin 2. Europium-labelled, non-irradiated phytohaemagluttinin-stimulated target cells from the parent were added to the culture after 7 days incubation. Target cell lysis was quantified by time resolved fluorometry. CsA-mediated inhibition of target cell lysis was calculated and used to compare individual responses to the drug. Two-colour flow cytometry was performed to identify activated subsets of lymphocytes at varying concentrations of CsA.


RESULTS
Wide inter-individual variations in per cent lysis and per cent inhibition were observed in patients and controls. Immunophenotyping indicated expansion of CD8(+) and CD25(+) lymphocyte subsets following allo-stimulation that was inhibited by increasing concentrations of CsA. Eight out of 13 patients and four out of 10 controls were "sensitive" to CsA in vitro in that they achieved 50% inhibition of cell lysis (IC(50)) at low concentrations of the drug (<50 ng/ml). Eleven patients have subsequently received a renal transplant. Five out of seven of these patients with IC(50) <50 ng/ml have suffered problems with infection, nephrotoxicity and graft vasculopathy raising the possibility of "over-immunosuppression".


CONCLUSIONS
The data imply a useful role for this model in the prediction of individual response to immunosuppression following allo-stimulation in the pre-transplant setting.
Dudley
Jan
J
University of Bristol Department of Transplantation Sciences, Paul O'Gorman Lifeline Centre, Southmead Hospital, Bristol BS10 5NB, UK. jandudley@yahoo.com
Truman
Carol
C
McGraw
Mary
M
Tizard
Jane
J
Haque
Gausal
G
Bradley
Ben
B
D000293:Adolescent; D002478:Cells, Cultured; D002648:Child; D002675:Child, Preschool; D016572:Cyclosporine / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D004351:Drug Resistance; D005260:Female; D006801:Humans; D016130:Immunophenotyping; D007166:Immunosuppressive Agents / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D020128:Inhibitory Concentration 50; D007519:Isoantigens / Q000276:immunology; D016030:Kidney Transplantation; D016131:Lymphocyte Subsets / Q000187:drug effects / Q000502:physiology; D008297:Male; D009000:Monocytes / Q000187:drug effects; D011183:Postoperative Complications / Q000139:chemically induced; D011379:Prognosis; D014850:Waiting Lists
D007166:Immunosuppressive Agents; D007519:Isoantigens; D016572:Cyclosporine