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More than ten years after the initial description of the humoral theory of transplantation by Dr. Paul I. Terasaki, the significance of humoral alloimmunity in liver transplantation has yet to be clearly defined. The liver allograft has an inherent tolerogenic capacity which confers its resistance to cell-mediated as well as antibody-mediated rejection. Nevertheless, the protection against alloimmunity is not complete, and antibody-mediated tissue injury can occur in the liver graft under specific circumstances. In this article the evidence on the clinicopathologic effects of donor-specific alloantibodies in liver transplantation will be examined and interpreted in parallel with lessons learned from renal transplantation. The unique anatomic and immunologic features of the liver will be reviewed to gain new insights into the complex interactions between humoral immune system and the liver allograft., Competing Interests: The author declares that there is no conflict of interests regarding the publication of this paper.

Advances in immunosuppression (IS) agents and strategies have resulted in reduced rejection rates and improved survival outcomes after liver transplantation. The use of induction and maintenance IS agents is both associated with reductions in acute rejection (AR) risk within the first 6 to 12 months posttransplant and with superior failure-free survival. With the lowered incidence of allograft losses attributable to rejection, the long-term sequelae of IS have become the major therapeutic challenge. The long-term use of calcineurin inhibitors and corticosteroids in maintenance immunotherapy regimens has been implicated in the development of renal dysfunction, infections, metabolic derangements, de novo and recurrent malignancies, and the propagation of hepatitis C virus reinfection. Our analysis of the United Network for Organ Sharing registry shows the use of induction and maintenance therapy is each associated with reductions in AR risk, thereby improving post-transplant survival. The administration of intensive induction regimens appears to be safe and exhibits an additive beneficial effect. Therefore, the use of intensive induction regimens may be warranted to allow for reductions in long-term maintenance IS to minimize drug toxicities while preserving graft outcomes.

ImportanceSerum α-fetoprotein (AFP) is a biomarker for hepatocellular carcinomas (HCCs) associated with a more aggressive tumor phenotype and inferior outcomes after a liver transplant (LT). Data on the outcomes for patients with HCCs that do not produce AFP are limited.ObjectiveTo compare characteristics and outcomes among LT recipients with radiographically apparent HCC lesions with AFP-producing tumors or with tumors that do not produce AFP (hereafter referred to as non-AFP-producing tumors), and to identify factors influencing recurrence in LT recipients with non-AFP-producing tumors.Design, setting, and participantsRetrospective analysis at a university transplant center of 665 adults with HCC who underwent an LT during the period from 1989 to 2013. Of the 665 LT recipients, 457 (68.7%) had AFP-producing tumors, and 208 (31.3%) had non-AFP-producing tumors (the maximum AFP level before an LT was ≤10 ng/mL). Dates of study analysis were from August 2015 to June 2016.InterventionLiver transplant.Main outcomes and measuresRecurrence-free survival and recurrence rates.ResultsPatients with non-AFP-producing tumors had radiographic tumor characteristics similar to those of patients with AFP-producing tumors, but, pathologically, they had fewer lesions (25% vs 35% with >2 lesions; P = .03), smaller cumulative tumor diameters (4.2 vs 5.0 cm; P = .02), fewer microvascular (17% vs 22%) and macrovascular (2% vs 9%) invasions (P 2 tumors [HR, 4.98; 95% CI, 1.72-14.4; P = .003]; cumulative diameter [1.70 per log SD; 1.12-2.59; P 2 tumors [4.39; 1.32-14.6; P = .02]; cumulative diameter [2.32 per log SD; 1.43-3.77; P = .001]; microvascular [3.07; 1.02-9.24; P = .05] and macrovascular invasion [8.75; 2.15-35.6; P = .002]).Conclusions and relevanceNearly one-third of patients with radiographically apparent HCC have non-AFP-producing tumors that have more favorable pathologic characteristics, lower posttransplant recurrence, and superior survival compared with patients with AFP-producing tumors. Posttransplant HCC recurrence for patients with non-AFP-producing tumors is predicted by important radiologic and pathologic factors, and is negligible for patients within the Milan criteria. Stratifying patients by AFP status in addition to radiological criteria may improve the selection process for and the prioritization of transplant candidates.