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Grand RoundsWeekly Evidence Brief

Transplant Surgery

Edition

30-Second Takeaway

  • Low-MELD candidates derive substantial survival benefit from liver transplant, challenging current acuity-based allocation thresholds.
  • Donor–recipient age matching in adolescent liver transplant significantly affects 10-year graft survival and should guide organ acceptance and sharing policy.
  • Xenotransplantation demands combined targeting of T cells, NK cells, and innate pathways, with donor cfDNA as a promising rejection biomarker.

Week ending January 10, 2026

Transplant Grand Rounds: Allocation, Environment, and Evolving Immunobiology Across Allo- and Xenotransplantation

First-in-human profiling maps early immune dynamics of a gene-edited pig kidney in a living recipient

NATURE MEDICINEJan 9, 2026

A living human recipient of a gene-edited pig kidney underwent intensive immune profiling with multi-omics and tissue imaging. Despite profound circulating T-cell depletion, early T cell–mediated rejection developed within one week, likely from residual lymph node CD8+ T cells and subtherapeutic immunosuppression. Rejection reversed after intensifying immunosuppression, leaving adaptive responses suppressed but with persistent monocyte–macrophage activation and elevated IL-1β and GM-CSF. Transcriptomics showed xenograft rejection signatures overlapping human allograft rejection, yet with distinct innate immune features and no antibody-mediated rejection detected.

Emulated trial shows clear survival gain from liver transplant even at MELD 6–14

TRANSPLANTATIONJan 6, 2026

A trial emulation paired adults listed for liver-only transplant and randomized them to transplant versus waitlist-only strategies using time-dependent propensity matching. Of 23,672 prematched candidates, 40% had MELD 6–14, yet fewer than one in five of these lower-MELD patients were transplanted. Waitlist patients had a 73% higher mortality risk than transplanted patients, and waitlist-only patients had nearly threefold higher mortality during follow-up. Survival benefit from transplantation persisted across MELD 6–14 and 15–24 strata, indicating meaningful advantage even at low MELD scores.

≥10-year donor–recipient age mismatch compromises 10-year graft survival in adolescent liver recipients

JAMA NETWORK OPENJan 7, 2026

This nationwide case-control study analyzed adolescents aged 12–17 receiving liver-only grafts from brain-dead donors between 2002 and 2024. Thirty percent received age-mismatched grafts with donor–recipient age difference ≥10 years, from substantially older donors than age-matched recipients. After propensity matching, 10-year graft survival was 61.5% with age-mismatched grafts versus 74.2% with age-matched grafts, a significant deficit. Inferior graft survival with age-mismatched livers was consistent across pretransplant hospitalization and ICU subgroups.

Network meta-analysis supports AFP-based Metroticket 2.0 as leading expanded HCC transplant criterion

CLINICAL AND MOLECULAR HEPATOLOGYJan 9, 2026

A network meta-analysis of 35 studies compared overall and recurrence-free survival for HCC patients within Milan criteria versus eight expanded criteria after liver transplant. UCSF, Up-to-Seven, and Hangzhou criteria were associated with worse overall survival than Milan, indicating oncologic trade-offs when expanding too broadly. Milan ranked best overall, but Metroticket 2.0 and Asan criteria showed comparable performance on overall and recurrence-free survival metrics. In a 1,008-patient validation cohort, Metroticket 2.0 and AFP-based models produced the most favorable HCC-specific mortality among expanded criteria.

References

Numbered in order of appearance. Click any reference to view details.

Additional Reads

Optional additional studies from this edition.

Edition context

Clinical signal

  • Human and primate xenotransplant studies together highlight complementary roles of residual T cells, NK cells, and innate activation in xenograft injury.
  • Trial emulation and registry data provide strong, practice-relevant signals favoring earlier liver transplantation and better age-matching for adolescents.
  • AFP-based expanded HCC criteria, particularly Metroticket 2.0, offer a rational path to broaden selection while preserving oncologic outcomes.