Pediatr Transplantation 2015: 19: 244–245
© 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
Pediatric Transplantation DOI: 10.1111/petr.12431
Letter to the Editor Donor age and operational tolerance in living donor liver transplantation Some studies have found that recipient age is related to operational tolerance (OT) after living donor liver transplantation (LDLT) (1). However, few studies have investigated the impact of donor age on OT in LDLT. We reported that our pilot study indicated that donor age is a crucial factor affecting telomere length sustainability in hepatocytes after LDLT and that the telomeres in grafted livers may be elongated somewhat longer when the grafts are immunologically well controlled (2). Therefore, we think that there is a clinical significance of donor age in OT after LDLT. As to a surveillance after OT, it has recently been reported that histopathological assessments using protocol liver biopsy (PLB) are important (1). Because graft liver dysfunction does not occur if the fibrosis does not become advanced, it is not possible to predict the occurrence of graft liver fibrosis or portal inflammation using standard liver function test alone (3). We reported that our pilot study indicated that PLB in patients with the long-term survival is an excellent examination for detecting early reversible graft fibrosis because no serum markers reflect this finding (4). Therefore, we think that there is a clinical significance of PLB in patients with OT after LDLT as a surveillance tool. Between June 1991 and November 2004, 109 LDLTs were performed for patients with nonrecurrence of original diseases using parental and grandparental grafts in our department and other facilities. We performed univariate analyses to identify the factors associated with OT. We performed a PLB after OT and assessed the histopathological findings using the METAVIR scoring system, including A (activity) and F (fibrosis). The overall incidence rate of OT after LDLT in the patients was 21.1%. The median period between LDLT and withdrawal of immunosuppressants was 7.4 yr (0.4–11.8), and the median observation period after OT was 7.0 yr 244
Table 1. Impact of donor age on OT Donor age
Gr-Tol
Gr-IS
Rate of OT (%)
p-value
© 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
Pediatric Transplantation DOI: 10.1111/petr.12431
Letter to the Editor Donor age and operational tolerance in living donor liver transplantation Some studies have found that recipient age is related to operational tolerance (OT) after living donor liver transplantation (LDLT) (1). However, few studies have investigated the impact of donor age on OT in LDLT. We reported that our pilot study indicated that donor age is a crucial factor affecting telomere length sustainability in hepatocytes after LDLT and that the telomeres in grafted livers may be elongated somewhat longer when the grafts are immunologically well controlled (2). Therefore, we think that there is a clinical significance of donor age in OT after LDLT. As to a surveillance after OT, it has recently been reported that histopathological assessments using protocol liver biopsy (PLB) are important (1). Because graft liver dysfunction does not occur if the fibrosis does not become advanced, it is not possible to predict the occurrence of graft liver fibrosis or portal inflammation using standard liver function test alone (3). We reported that our pilot study indicated that PLB in patients with the long-term survival is an excellent examination for detecting early reversible graft fibrosis because no serum markers reflect this finding (4). Therefore, we think that there is a clinical significance of PLB in patients with OT after LDLT as a surveillance tool. Between June 1991 and November 2004, 109 LDLTs were performed for patients with nonrecurrence of original diseases using parental and grandparental grafts in our department and other facilities. We performed univariate analyses to identify the factors associated with OT. We performed a PLB after OT and assessed the histopathological findings using the METAVIR scoring system, including A (activity) and F (fibrosis). The overall incidence rate of OT after LDLT in the patients was 21.1%. The median period between LDLT and withdrawal of immunosuppressants was 7.4 yr (0.4–11.8), and the median observation period after OT was 7.0 yr 244
Table 1. Impact of donor age on OT Donor age
Gr-Tol
Gr-IS
Rate of OT (%)
p-value
