The clinical significance of early histological rejection with or without biochemical abnormality in adult living donor liver transplantation for hepatitis B virus related end stage liver disease

Immunologic Outcomes in Cross-Sex Solid Organ Transplants: A Systematic Review and Meta-Analysis to Inform Vascularized Composite Allotransplantation

BACKGROUND

Of nearly 90 hand and 50 face transplant recipients, only five have received a cross-sex vascularized composite allotransplantation (CS-VCA). CS-VCA has the potential to expand the donor pool and has been proven anatomically feasible and ethically acceptable in previous studies. However, there is a lack of immunologic data. This study evaluated the immunologic feasibility of CS-VCA through analysis of the solid organ transplant literature, given the paucity of CS-VCA data. The authors hypothesize that rates of acute rejection (AR) and graft survival (GS) in CS versus same-sex (SS) solid organ transplantation are similar.

METHODS

A systematic review and meta-analysis were performed. Studies comparing GS or AR episodes in CS and SS adult kidney (KT) and liver transplant (LT) populations were included. Odds ratios were calculated for overall GS and AR for all SS and CS transplant combinations [male-to-female (MTF), female-to-male, and overall].

RESULTS

A total of 693 articles were initially identified with 25 included in the meta-analysis. No significant difference in GS was noted between SS-KT versus CS-KT [OR, 1.04 (95% CI, 1.00 to 1.07); P = 0.07), SS-KT versus MTF-KT [OR, 0.97 (95% CI, 0.90 to 1.04); P = 0.41), and SS-LT versus MTF-LT [OR, 0.95 (95% CI, 0.91 to 1.00); P = 0.05). No significant difference in AR was noted between SS-KT versus MTF-KT [OR, 0.99 (95% CI, 0.96 to 1.02); P = 0.57), SS-LT versus CS-LT [OR, 0.78 (95% CI, 0.53 to 1.16); P = 0.22], or SS-LT versus female-to-male LT [OR, 1.03 (95% CI, 0.95 to 1.12); P = 0.47]. For the remaining pairings, GS was significantly increased and AR was significantly decreased in the SS transplants.

CONCLUSIONS

Published data suggest immunologic feasibility of CS-KT and CS-LT with the potential for generalization to the VCA population.

CLINICAL RELEVANCE STATEMENT

In theory, CS-VCA could expand the potential donor pool, ultimately leading to decreased wait times for recipients and improve the likelihood of establishing a immunologically favorable donor-recipient match.

Elevated fractional donor-derived cell-free DNA during subclinical graft injury after liver transplantation

Personalized immunosuppression (IS) promises to improve the balance of necessary control of alloreactivity and dose-dependent adverse effects of long-term IS such as kidney insufficiency, infections, and malignancies. The majority of liver transplantation (LT) recipients exhibit graft injuries (graft inflammation and/or fibrosis) that are not eligible for an IS reduction according to current Banff criteria, even when liver enzymes are normal or only marginally elevated. This cross-sectional study evaluated the noninvasive prediction of such subclinical graft injuries in surveillance liver biopsies via donor-derived cell-free DNA (dd-cfDNA). Absolute and fractional dd-cfDNA increased stepwise from patients without histological signs of rejection (n = 26) over subclinical graft injury (n = 61), including subclinical T cell-mediated rejection to clinical overt T cell-mediated rejection (n = 21). Thus, fractional plasma dd-cfDNA was significantly elevated paired to surveillance biopsies with relevant subclinical graft injury according to 2016 Banff criteria compared with those with minimal or absent histological graft injury. In contrast, the presence of donor-specific anti-human leukocyte antigen antibodies was not associated with the amount of dd-cfDNA. The sensitivity and specificity of fractional dd-cfDNA to noninvasively predict relevant subclinical graft injury was rather limited with 73% and 52% at the cutoff value of 2.1% fractional dd-cfDNA. The positive predictive value of fractional dd-cfDNA above 2.1% was 76% to noninvasively predict subclinical graft injury, calculated on the prevalence of graft injury in our prospective surveillance biopsy program, whereas the negative predictive values was not predictive (47%). In conclusion, dd-cfDNA has a rather limited diagnostic fidelity in addition to other noninvasive markers for the assessment of subclinical graft injury in personalized IS approaches after LT in a cross-sectional setting.

Evaluation of Graft Fibrosis, Inflammation and Donor-specific Antibodies at Protocol Liver Biopsies in Pediatric Liver Transplant Patients: a Single Center Experience

BACKGROUND

The impact of graft fibrosis and inflammation on the natural history of pediatric liver transplants (LT) is still debated. Our objectives were to evaluate the evolution of posttransplant fibrosis and inflammation over time at protocol liver biopsies (PLBs), risk factors for fibrosis, presence of donor-specific antibodies (DSAs) and/or their correlation with graft and recipient factors.

METHODS

A single-center, retrospective (2000-2019) cross-sectional study on pediatric LT recipients who had at least one PLB, followed by a longitudinal evaluation in those who had at least two PLBs, was conducted. Fibrosis was assessed by the Liver Allograft Fibrosis Semiquantitative score, inflammation by the Rejection Activity Index, DSAs by Luminex®.

RESULTS

A total of 134 PLBs from 94 patients were included. Fibrosis was detected in 87% (30% mild, 45% moderate, 12% severe), 80% in the portal tracts. There was an increase in fibrosis between the 1-3 and the 4-6 year group (p=0.01), then it was stable. Inflammation was observed in 44% (30% mild, 13% moderate, 1% severe), 90% in the portal tracts. Anti-HLA II (IgG) DSAs were detected in 14/40 (35%). Portal fibrosis was associated with portal inflammation in the 1-3 year group (p=0.04). Low immunosuppression levels were correlated with sinusoidal fibrosis (p=0.04) and DSA positivity (p-value=0.006). There was no statistically significant correlation between DSA positivity and the presence of graft fibrosis or inflammation.

CONCLUSIONS

This study corroborates the concept of an early evolution of silent graft fibrosis. Suboptimal immunosuppression may play a role in the development of fibrosis and DSAs.

DSA Are Associated With More Graft Injury, More Fibrosis, and Upregulation of Rejection-associated Transcripts in Subclinical Rejection

BACKGROUND

Subclinical T cell-mediated rejection (subTCMR) is commonly found after liver transplantation and has a good short-term prognosis, even when it is left untreated. Donor-specific antibodies (DSA) are putatively associated with a worse prognosis for recipient and graft after liver transplantation.

METHODS

To assess the immune regulation in subTCMR grafts, gene expression of 93 transcripts for graft injury, tolerance, and immune regulation was analyzed in 77 biopsies with "no histologic rejection" (NHR; n = 25), "clinical TCMR" (cTMCR; n = 16), and subTCMR (n = 36). In addition, all available subTCMR biopsies (n = 71) were tested for DSA with bead assays.

RESULTS

SubTCMR showed heterogeneous and intermediate expression profiles of transcripts that were upregulated in cTCMR. Graft gene expression suggested a lower activation of effector lymphocytes and a higher activation of regulatory T cells in grafts with subTCMR compared to cTCMR. DSA positivity in subTCMR was associated with histological evidence of more severe graft inflammation and fibrosis. This more severe DSA+ associated graft injury in subTCMR was converged with an upregulation of cTCMR-associated transcripts. In nonsupervised analysis, DSA positive subTCMR mostly clustered together with cTCMR, while DSA negative subTCMR clustered together with NHR.

CONCLUSIONS

T cell-mediated rejection seems to form a continuum of alloimmune activation. Although subTCMR exhibited less expression of TCMR-associated transcript, DSA positivity in subTCMR was associated with an upregulation of rejection-associated transcripts. The identification of DSA positive subclinical rejection might help to define patients with more inflammation in the graft and development of fibrosis.

Non-invasive screening for subclinical liver graft injury in adults via donor-specific anti-HLA antibodies

The majority of liver grafts exhibit abnormal histological findings late after transplantation, even when liver enzymes are normal. Such subclinical graft injuries were associated with rejection and fibrosis progression in recent studies. The identification of non-invasive biomarkers for subclinical graft injury might help to individualize immunosuppression. Therefore, graft injury was assessed in 133 liver biopsies with normal/near normal liver enzymes from a prospective liver biopsy program. Cytokeratin-18 cell death marker (M65) and donor specific anti-HLA antibodies (DSA) were measured as non-invasive markers in paired plasma samples in addition to routine parameters. M65 was associated with subclinical graft injury but this association was too weak for reasonable clinical application. DSA positivity was associated with more graft inflammation (OR = 5.4) and more fibrosis (OR = 4.2). Absence of DSA excluded fibrosis in 87–89%, while presence of DSA excluded histological criteria for immunosuppression minimization attempts in 92–97%. While CK18 cell death marker had no diagnostic value for the detection of subclinical liver graft injury, DSA testing can help to preselect patients for immunosuppression reduction in case of DSA negativity, while DSA positivity should prompt elastography or liver biopsy for the assessment of subclinical graft injury.

Contrast-Enhanced Ultrasound Using Perfluorobutane-Containing Microbubbles in the Assessment of Liver Allograft Damage: An Exploratory Prospective Study

This prospective study investigated the usefulness of contrast (perfluorobutane-containing microbubbles)-enhanced ultrasound in the non-invasive assessment of liver allograft damage. Forty-one liver recipients underwent contrast-enhanced ultrasound followed by a liver biopsy. The hepatic filling rate (time between the arrival of contrast agent in the right hepatic artery and the maximum intensity of hepatic parenchyma) and parenchymal intensity difference before and after instantaneous high-power emission in the Kupffer phase were measured. Patients with allograft damage had higher hepatic filling rates and lower parenchymal intensity differences than those without damage (42.0 ± 16.9 vs. 30.5 ± 7.7 s, p = 0.005; 6.1 ± 7.4 vs. 16.6 ± 16.1 dB, p = 0.047, respectively). In the diagnosis of liver allograft damage, hepatic filling rate and parenchymal intensity difference had sensitivities of 61.5% and 90.9% and specificities of 92.6% and 63.6% using cutoffs of >38.5 s and ≤10.3 dB, respectively. In conclusion, contrast-enhanced ultrasound may be a promising tool in the detection of liver allograft damage.

Preferential accumulation of T helper cells but not cytotoxic T cells characterizes benign subclinical rejection of human liver allografts

Subclinical rejection (SCR) is a common event in protocol biopsies after liver transplantation (LT). So far the interpretation of the underlying histological changes and clinical significance is limited. Previous studies were restricted to SCR manifestations within the first weeks after transplantation with limited follow-up. We analyzed clinical data from our prospective protocol biopsy program and found late SCR (at least 3 months after transplantation) to be a common event (41/94 patients). SCR manifested much later than acute cellular rejection (ACR). In the second year after transplantation, the SCR incidence in protocol biopsies reached a plateau of approximately 25% and remained at this level until the latest observed manifestations more than 5 years after transplantation. During a median follow-up of 32 months after SCR, no acute or chronic rejection, relevant graft fibrosis, graft loss, or liver-related death occurred even without specific therapy for SCR. Immunophenotyping of liver biopsies during SCR showed that similar to ACR, the composition of intrahepatic T cells depended on the severity of histological rejection. However, SCR showed a different pattern of infiltrating T cells with a stronger accumulation of CD4(+) cells, an increasing CD4(+) /CD8(+) ratio, and an increasing CD4(+) forkhead box P3 (FOXP3)(+) regulatory T cell (Treg)/CD8(+) ratio, which was not seen in ACR. These intrahepatic T cell patterns were not reflected in the peripheral blood. In conclusion, late SCR after LT has a good clinical prognosis, and it seems safe to leave it untreated. This benign clinical course compared to ACR is associated with intrahepatic T cell infiltration patterns showing less cytotoxic T cells and more CD4(+) FOXP3(+) Tregs. Liver Transplantation 22 943-955 2016 AASLD.

Female donor to male recipient gender discordance results in inferior graft survival: a prospective study of 1,042 liver transplants

BACKGROUND

The influence of donor-recipient gender mismatch on outcomes after liver transplantation (LT) is controversial. The aim of this study was to evaluate the effect of donor and recipient gender discordance on graft survival.

METHODS

All patients who underwent primary LT from 1994-2012 at a single-center were identified prospectively. Clinico-demographic data were collected at the time of LT and last follow-up. Gender match included both male donor to male recipient (MM) and female donor to female recipient (FF), while gender mismatch included female donor to male recipient (FM) and male donor to female recipient (MF). Survival curves for graft survival were generated using Kaplan-Meier method and compared by log-rank test. Unadjusted and multivariate adjusted COX regression analyzing graft survival at up to 10 years post-transplant was performed.

RESULTS

A total of 1,042 subjects fulfilled the criteria. Graft survival in patients receiving a donor-recipient gender match was better than those receiving a gender mismatch (P = 0.047). Female-to-male transplants had the worst graft survival of all combinations (P < 0.001); this difference was maintained in multivariate regression after adjustment for recipient and donor variables (hazards ratio 2.09, P = 0.013).

CONCLUSION

Female-to-male liver transplants are associated with a statistically significant poorer graft survival as compared with other donor-recipient gender groups.

New prediction factors of small-for-size syndrome in living donor adult liver transplantation for chronic liver disease

Small-for-size syndrome (SFSS), which is characterized by synthetic dysfunction and prolonged cholestasis, is a major cause of worse short-term prognoses after living donor adult liver transplantation (LDALT). However, the risks of SFSS remain unclear. The aim of this study was to clarify the risks of SFSS, which were analysed in 172 patients who underwent LDALT for chronic liver disease. Graft types included left lobe with caudate lobe graft (n = 110) and right lobe graft (n = 62). Thirty-four cases (24 with left lobe grafts and 10 with right lobe grafts) were determined as SFSS. SFSS developed even if the actual graft-to-recipient standard liver volume ratio was >40%. Logistic regression analysis revealed three independent factors associated with SFSS development in left and right lobe grafts: donor age, actual graft-to-recipient native liver volume ratio, and Child's score. Donor age and actual graft-to-recipient native liver volume ratio may become predictive factors for SFSS development in left and right lobe grafts in patients undergoing LDALT.