DEFINING THE OUTCOME OF IMMUNOSUPPRESSION WITHDRAWAL AFTER LIVER-TRANSPLANTATION

Successful immunosuppression withdrawal should benefit the natural his tory of organ transplantation patients, To identify the clinical hazar ds of removing drug treatment and possible characteristics that predic t a favorable outcome in long-term liver recipients, immunosuppression was withdrawn completely and the clinicopathological outcome document ed in 18 liver recipients. Indication for transplantation, HLA matchin g, early rejection history, and presence of microchimerism were examin ed as predictors of outcome, Chimerism was determined by polymerase ch ain reaction-based examination for donor-specific HLA-DRB1 alleles and Y-gene-specific nucleotide sequences. At 3 years, 5 patients (28%) re mained completely off immunosuppression; 12 patients (67%) experienced histological graft changes: acute rejection in 4, portal tract inflam mation/ hepatitis in 7, and necrosis in 1, Hepatitis B or C viral infe ctions did not account for the nonrejection patterns, Unmasking of sys temic disorders occurred. Chimerism, demonstrated in 7 patients (39%), with skin the optimal tissue, was not associated with tolerance. Para meters associated with successful drug withdrawal were transplantation for non-immune-mediated liver disorders, fewer donor-recipient HLA A, B, and DR mismatches, and a low incidence of early rejection, Immunos uppression withdrawal is a feasible option in a proportion of selected liver recipients, but identification of tolerant patients remains imp recise.