Monitoring the operationally tolerant liver allograft recipient.
OBJECTIVE
A fundamental goal in transplantation is the establishment of allograft function without ongoing immunosuppression. Robust allograft tolerance has been established in experimental transplantation models, whereas clinical operational tolerance has been described most frequently following human liver transplantation.


RESULTS
Clinical assessment of tolerance has been limited to laboratory evaluation of organ function. Additional tools include graft monitoring through biopsy and blood sampling for biomarker analysis. Current biomarkers under assessment in recent years include dendritic cell subsets, regulatory T cells, antidonor antibodies, and gene polymorphisms. Emerging microarray analysis that is being prospectively validated will also be reviewed. A further tool in the characterization of the tolerant patient will be the accurate enrollment of such patients into a multicenter registry that will prospectively follow the natural history of the patient withdrawn from immunosuppression and help facilitate the entry of interested patients to mechanistic and immune monitoring trials. The International Solid Organ Transplant Tolerance Registry (www.transplant-tolerance.org) will be briefly described.


CONCLUSIONS
Effective biomarker characterization of the operationally tolerant liver allograft recipient would allow earlier, well tolerated, prospective drug withdrawal with the goal of extending the potential benefits of drug minimization to an increasing number of patients in a more predictable fashion.
Castellaneta
Antonino
A
Children's Hospital of Pittsburgh (CHP) Hillman Center for Pediatric Transplantation, Pittsburgh, Pennsylvania 15224, USA.
Thomson
Angus W
AW
Nayyar
Navdeep
N
de Vera
Michael
M
Mazariegos
George V
GV
D015415:Biomarkers / Q000097:blood*; D001706:Biopsy; D004334:Drug Administration Schedule; D006084:Graft Rejection / Q000175:diagnosis* / Q000235:genetics / Q000276:immunology / Q000517:prevention & control; D006085:Graft Survival; D006801:Humans; D007166:Immunosuppressive Agents / Q000008:administration & dosage; D008111:Liver Function Tests; D016031:Liver Transplantation / Q000009:adverse effects*; D046228:Microarray Analysis; D011237:Predictive Value of Tests; D012042:Registries; D016176:T-Lymphocyte Subsets / Q000276:immunology; D013997:Time Factors; D023001:Transplantation Tolerance; D014184:Transplantation, Homologous; D016896:Treatment Outcome
D015415:Biomarkers; D007166:Immunosuppressive Agents