Analysis of the effects of donor and recipient hepatitis C infection on kidney transplant outcomes in the United States.

BACKGROUND: As Hepatitis C virus infection (HCV+) rates in kidney donors and transplant recipients rise, direct-acting antivirals (DAA) may affect outcomes. AIM: To analyze the effects of HCV+ in donors, recipients, or both, on deceased-donor (DD) kidney transplantation (KT) outcomes, and the impact of DAAs on those effects. METHODS: The Organ Procurement and Transplantation Network data of adult first solitary DD-KT recipients 1994-2019 were allocated into four groups by donor and recipient HCV+ status. We performed patient survival (PS) and death-censored graft survival (DCGS) pairwise comparisons after propensity score matching to assess the effects of HCV+ in donors and/or recipients, stratifying our study by DAA era to evaluate potential effect modification. RESULTS: Pre-DAA, for HCV+ recipients, receiving an HCV+ kidney was associated with 1.28-fold higher mortality (HR 1.151.281.42) and 1.22-fold higher death-censored graft failure (HR 1.081.221.39) compared to receiving an HCV- kidney and the absolute risk difference was 3.3% (95%CI: 1.8%-4.7%) for PS and 3.1% (95%CI: 1.2%-5%) for DCGS at 3 years. The HCV dual-infection (donor plus recipient) group had worse PS (0.56-fold) and DCGS (0.71-fold) than the dual-uninfected. Donor HCV+ derived worse post-transplant outcomes than recipient HCV+ (PS 0.36-fold, DCGS 0.34-fold). In the DAA era, the risk associated with HCV+ in donors and/or recipients was no longer statistically significant, except for impaired PS in the dual-infected vs dual-uninfected (0.43-fold). CONCLUSION: Prior to DAA introduction, donor HCV+ negatively influenced kidney transplant outcomes in all recipients, while recipient infection only relatively impaired outcomes for uninfected donors. These adverse effects disappeared with the introduction of DAA.

Establishment of an Ex Vivo Tissue Culture Model for Evaluation of Antitumor Efficacy in Clear Cell Renal Cell Carcinoma.

There are many potential immunotherapeutic targets for cancer immunotherapy, which should be assessed for efficacy before they enter clinical trials. Here we established an ex vivo cultured patient-derived tumor tissue model to evaluate antitumor effectiveness of one VISTA inhibitor, given that our previous study showed that VISTA was selectively highly expressed in human clear cell renal cell carcinoma (ccRCC) tumors. We observed that all the tested patients responded to the anti-VISTA monoclonal antibody as manifested by TNF-α production, but only a small fraction were responders to the anti-PD-1 antibody. Co-blockade of VISTA and PD-1 resulted in a synergistic effect in 20% of RCC patients. Taken together, these findings indicate that this ex vivo tumor slice culture model represents a viable tool to evaluate antitumor efficacies for the inhibitors of immune checkpoints and further supports that VISTA could serve as a promising target for immunotherapy in ccRCC.

Temporal trends and impact of willingness to accept organs from donors with hepatitis C virus.

Direct-acting antivirals (DAA) transformed hepatitis C virus (HCV) treatment in 2014; however, their impact on transplant candidates' willingness to accept (CWTA) organs from HCV+ donors remains uncertain. We retrospectively studied Organ Procurement and Transplantation Network data from 2008 to 2019, investigating CWTA different organs from HCV+ donors over time, using segmented multivariable logistic regression, and how that influenced wait-time and deceased-donor transplantation (DDTx) probability, using multivariable logistic or linear regression. We found that DAA availability was associated with a marked increase in CWTA in all organs from HCV+ donors except intestine. By December 2020, 40% of kidney, 33% of kidney-pancreas, 42% of pancreas, over 50% of liver, heart, lung, heart-lung, and 9% of intestine candidates waitlisted were CWTA an organ from HCV+ donors. Compared with pre-DAA, yearly CWTA kidney from HCV+ donors increased post-DAA 1.78 1.811.83 -fold, kidney-pancreas 2 .52 2.78 3.07 -fold, pancreas 3.15 3.69 4.43 -fold, liver 1.53 1.541.56 -fold, heart 1 .92 2.02 .08 -fold, and lung 2.00 2.12 .20 -fold. CWTA kidney and liver from HCV+ donors significantly increased DDTx probability post-DAA (1.98 2.042.1 -fold and 1.24 1.291.33 -fold, respectively) and shortened kidney candidates' wait-time78 90101 days (Mean with 95% CI). CWTA organs from HCV+ donors rose significantly with DAA availability, benefitting kidney and liver candidates with increased DDTx rates and shortened kidney candidates' wait time. Further long-term outcomes investigation and standardized organ from HCV+ donors' education could improve both provider and patient acceptance and utilization.

Influence of donor and recipient hepatitis B virus infection on long-term outcomes after kidney transplantation.

BACKGROUND: The demand for transplantable kidneys continues to outstrip supply, and the risk of donor-derived infection limits utilization. The effect of donor or recipient HBV status, defined by surface antigen (HBsAg) positivity, on long-term survival outcomes of kidney transplant (KT) is unknown. METHODS: We conducted a retrospective cohort study based on Organ Procurement and Transplantation Network (OPTN) data from 2000 to 2019. We identified three cohorts based on donor (D) or recipient (R) HBsAg status: D-R, D-R+, and D+R-. Pairwise comparisons of patient survival (PS) and all-cause graft survival (GS) after propensity score matching were performed to assess the effect of HBV infection in KT recipients. RESULTS: Our findings showed that there were no statistically significant differences in PS and GS among D-R, D-R+, and D+R-groups, nor was the patient or GS different between donor and recipient HBsAg+ status. Finally, in 2019 kidney discard rates were 15% higher for HBsAg+ deceased donors compared to HBsAg- donors. CONCLUSIONS: HBsAg+ status was not associated with worse PS or GS after KT. Prior to broadly advocating utilization of HbsAg+ kidneys, further studies assessing KT recipient morbidity and safety are necessary.

Effect of Recipient Hepatitis C Status on Outcomes of Deceased Donor Kidney Transplantation.

BACKGROUND: Hepatitis C virus (HCV) infection has been deemed detrimental to kidney transplantation (KT) outcomes. Breakthrough HCV treatment with direct-acting antiviral (DAA) medications improved the probability of HCV+ kidney use for KT even in noninfected (HCV-) recipients. We hypothesized that recipient HCV infection influences deceased donor KT outcomes, and this effect could be modified by donor HCV status and use of DAAs. STUDY DESIGN: We conducted a retrospective cohort study based on data from the Organ Procurement and Transplantation Network as of September 2018. A mate kidneys analysis was performed with HCV+ and HCV- recipients of solitary adult KT from ABO-compatible deceased donor between January 1994 and June 2018. We selected donors where 1 KT recipient was HCV+ and the mate kidney recipient was HCV-. Both HCV- and HCV+ donors were identified and analyzed separately. Outcomes, including survival of patients, grafts, and death-censored grafts, were compared between the groups. RESULTS: Four-hundred and twenty-five HCV+ and 5,575 HCV- donor mate kidneys were transplanted in HCV-discrepant recipients. HCV+ recipients of HCV- donor had worse patient and graft survival (adjusted hazard ratio 1.28; 95% CI, 1.19 to 1.37 and adjusted hazard ratio 1.26; 95% CI 1.18 to 1.34, respectively) and death-censored grafts (adjusted hazard ratio 1.24; 95% CI, 1.15 to 1.34) compared with HCV- recipients. Comparable patient and graft survival and death-censored grafts were found in recipients of HCV+ donors, regardless of recipient HCV status. The risk associated with HCV positivity in donors or recipients in the pre-DAA era (before December 2013) was no longer statistically significant in the post-DAA era. CONCLUSIONS: Given comparable outcomes between HCV+ and HCV- recipients in post-DAA era or when receiving HCV+ donor kidneys, broader use of HCV+ kidneys regardless of the recipient's HCV status should be advocated, and allocation algorithm for HCV+ kidneys should be revised.

Tumor-expressed B7-H3 mediates the inhibition of antitumor T-cell functions in ovarian cancer insensitive to PD-1 blockade therapy.

Although PD-L1/PD-1 blockade therapy has been approved to treat many types of cancers, the majority of patients with solid tumors do not respond well, but the underlying reason remains unclear. Here, we studied ovarian cancer (OvCa), a tumor type generally resistant to current immunotherapies, to investigate PD-1-independent immunosuppression. We found that PD-L1 was not highly expressed in the tumor microenvironment (TME) of human OvCa. Instead, B7-H3, another checkpoint molecule, was highly expressed by both tumor cells and tumor-infiltrating antigen-presenting cells (APCs), which correlated with T-cell exhaustion in patients. Using ID8 OvCa mouse models, we found that B7-H3 expressed on tumor cells, but not host cells, had a dominant role in suppressing antitumor immunity. Therapeutically, B7-H3 blockade, but not PD-1 blockade, prolonged the survival of ID8 tumor-bearing mice. Collectively, our results demonstrate that tumor-expressed B7-H3 inhibits the function of CD8+ T cells and suggest that B7-H3 may be a target in patients who are not responsive to PD-L1/PD-1 inhibition, particularly OvCa patients.

Expression of the inhibitory B7 family molecule VISTA in human colorectal carcinoma tumors.

Colorectal carcinoma (CRC) is one of the most common malignancies in the world. PD-1/PD-L1 inhibitors have benefited cancer patients with multiple tumor types. However, their efficacy for CRC is low and this treatment in melanoma patients results in adaptive resistance through upregulation of VISTA, another checkpoint inhibitory pathway. Thus, there is an urgent need to explore additional co-inhibitory molecular pathways such as VISTA for CRC treatment. In this study, C10orf54 (encoding VISTA) expression was analyzed by RNA-seq data from 367 CRC patients in human cancer datasets. Moreover, 28 clinical CRC specimens were used to assess VISTA protein expression. Human cancer datasets showed that CRC tumors expressed higher levels of C10orf54 than CD274 (encoding PD-L1). Moreover, C10orf54 mRNA expression was significantly correlated with genes responsible for tumor immune evasion. VISTA protein expression was high in tumors compared with para-tumors and normal tissues, which is similar to PD-L1 expression. However, in contrast to PD-L1, VISTA was mainly expressed by tumor-infiltrating lymphocytes. This study is the first investigation of VISTA expression in human resected CRC tumors, and the results justify the need for future studies on the role of VISTA in anti-CRC immunity in clinical samples.

IL-17C/IL-17RE Augments T Cell Function in Autoimmune Hepatitis.

Autoimmune hepatitis is a worldwide health problem and significant cause of mortality. However, the disease etiology is largely unknown, which accounts for ineffective treatment and uncontrolled disease progression. In this study, we demonstrated the functional importance of the IL-17C/IL-17RE axis in Con A-induced hepatitis. Elevated IL-17C expression was detected in liver samples of both human and mouse autoimmune hepatitis. IL-17C, produced by hepatocytes, and its specific receptor IL-17RE on liver-resident T cells were both found to be required in Con A-induced liver damage. Mechanistically, IL-17C augmented the expression of IL-2 by intrahepatic CD4+ T cells to promote NK cell activation and liver damage. To our knowledge, our findings thus for the first time defined the indispensable role of IL-17C/IL-17RE in autoimmune hepatitis; this axis may serve as a novel drug target for the treatment of this disease.

IL-17C is required for lethal inflammation during systemic fungal infection.

Within the interleukin-17 (IL-17) family of cytokines, IL-17A is known to be critical in the host defense against fungal infections; however, the function of the other IL-17 family members in anti-fungal immunity remains largely unknown. Here, we show that IL-17C expression was highly induced in kidney epithelial cells after fungal infection. Mice that lacked IL-17C exhibited increased survival and attenuated kidney tissue damage, although they had similar fungal loads. IL-17C deficiency resulted in decreased pro-inflammatory cytokine expression compared with wild-type control mice. Additionally, IL-17C directly acted on renal epithelial cells in vitro to promote pro-inflammatory cytokine production. Taken together, our data demonstrate that IL-17C is a critical factor that potentiates inflammatory responses and causes host injury during fungal infection.

SAHA, an HDAC inhibitor, attenuates antibody-mediated allograft rejection.

BACKGROUND: Antibody-mediated rejection (AMR) is gaining increasing recognition as a critical causative factor contributing to graft loss in organ transplantation. However, current therapeutic options for prevention and treatment of AMR are very limited and ineffective. The impact of epigenetic modification in B-cell function and its involvement in AMR is still yet to be explored. METHODS: The impacts of suberoylanilide hydroxamic acid (SAHA), a histone deacetylase inhibitor, on isolated murine B-cell viability, proliferation, apoptosis, expression of surface marker, and secretion of immunoglobulin and interleukin-10 were investigated. In vivo, a murine cardiac transplant model was used to evaluate the effect of SAHA on splenic B-cell subsets and on AMR in Rag1(-/-) recipient mice after reconstitution of allostimulated B cells. RESULTS: SAHA possesses capability to repress B-cell function. Specifically, SAHA is potent to decrease the viability of isolated B cells by inducing apoptosis. SAHA was also found capable of suppressing the expression of B-cell costimulatory molecules and, as a result, addition of SAHA into the cultures attenuated B-cell proliferation and immunoglobulin secretion. In line with these results, administration of SAHA significantly suppressed AMR in Rag1(-/-) recipient mice after reconstitution of allostimulated B cells along with enhanced cardiac allograft survival time. Mechanistic studies revealed that SAHA promotes B-cell secretion of interleukin-10. CONCLUSIONS: Our data support that SAHA could be a promising immunosuppressive agent with potential beneficial effect on prevention and treatment of AMR.

CD4(+)CD25(-)Nrp1(+) T cells synergize with rapamycin to prevent murine cardiac allorejection in immunocompetent recipients.

Besides CD4(+)CD25(+)Foxp3(+) regulatory T cells (Tregs), other immunosuppressive T cells also participated in the regulation of immune tolerance. Reportedly, neuropilin-1 (Nrp1) might be one of the molecules by which regulatory cells exert their suppressive effects. Indeed, CD4(+)CD25(-)Nrp1(+) T cells exhibit potent suppressive function in autoimmune inflammatory responses. Here we investigated the specific role of CD4(+)CD25(-)Nrp1(+) T cells in the setting of the transplant immune response. Through MLR assays, we found that CD4(+)CD25(-)Nrp1(+) T cells suppressed the proliferation of naive CD4(+)CD25(-) T cells activated by allogeneic antigen-stimulation. Adoptive transfer of CD4(+)CD25(-)Nrp1(+) T cells synergized with rapamycin to induce long-term graft survival in fully MHC-mismatched murine heart transplantation, which was associated with decreased IFN-γ, IL-17 and increased IL-10, TGF-ß, Foxp3 and Nrp1 expression in the grafts. Importantly, our data indicated that CD4(+)CD25(-)Nrp1(+) T cell transfer augments the accumulation of Tregs in the recipient, and creates conditions that favored induction of hyporesponsiveness of the T effector cells. In conclusion, this translational study indicates the possible therapeutic potential of CD4(+)CD25(-)Nrp1(+) T cells in preventing allorejection. CD4(+)Nrp1(+) T cells might therefore be used in bulk as a population of immunosuppressive cells with more beneficial properties concerning ex vivo isolation as compared to Foxp3(+) Tregs.

SAHA, an HDAC inhibitor, synergizes with tacrolimus to prevent murine cardiac allograft rejection.

Suberoylanilide hydroxamic acid (SAHA), as a histone deacetylase (HDAC) inhibitor (HDACi), was recently found to exhibit an immunosuppressive effect. However, whether SAHA can synergize with calcineurin inhibitors (CNIs) to inhibit allograft rejection and its underlying mechanism remain elusive. In this study, we demonstrated the synergistic effects of SAHA and non-therapeutic dose of tacrolimus (FK506) in prolonging the allograft survival in a murine cardiac transplant model. Concomitant intragraft examination revealed that allografts from SAHA-treated recipients showed significantly lower levels of IL-17 expression, and no discernable difference for IL-17 expressions was detected between SAHA- and SAHA/FK506-treated allograft as compared with allografts from FK506-treated animals. In contrast, administration of FK506 significantly suppressed interferon (IFN)-γ but increased IL-10 expression as compared with that of SAHA-treated animals, and this effect was independent of SAHA. Interestingly, SAHA synergizes with FK506 to promote Foxp3 and CTLA4 expression. In vitro, SAHA reduced the proportion of Th17 cells in isolated CD4⁺ T-cell population and decreased expressions of IL-17A, IL-17F, STAT3 and RORγt in these cells. Moreover, SAHA enhances suppressive function of regulatory T (Treg) cells by upregulating the expression of CTLA-4 without affecting T effector cell proliferation, and increased the proportion of Treg by selectively promoting apoptosis of T effector cells. Therefore, SAHA, a HDACi, may be a promising immunosuppressive agent with potential benefit in conjunction with CNI drugs.

Preconditioning with physiological levels of ethanol protect kidney against ischemia/reperfusion injury by modulating oxidative stress.

BACKGROUND: Oxidative stress due to excessive production of reactive oxygen species (ROS) and subsequent lipid peroxidation plays a critical role in renal ischemia/reperfusion (IR) injury. The purpose of current study is to demonstrate the effect of antecedent ethanol exposure on IR-induced renal injury by modulation of oxidative stress. MATERIALS AND METHODS: Bilateral renal warm IR was induced in male C57BL/6 mice after ethanol or saline administration. Blood ethanol concentration, kidney function, histological damage, inflammatory infiltration, cytokine production, oxidative stress, antioxidant capacity and Aldehyde dehydrogenase (ALDH) enzymatic activity were assessed to evaluate the impact of antecedent ethanol exposure on IR-induced renal injury. RESULTS: After bilateral kidney ischemia, mice preconditioned with physiological levels of ethanol displayed significantly preserved renal function along with less histological tubular damage as manifested by the reduced inflammatory infiltration and cytokine production. Mechanistic studies revealed that precondition of mice with physiological levels of ethanol 3 h before IR induction enhanced antioxidant capacity characterized by significantly higher superoxidase dismutase (SOD) activities. Our studies further demonstrated that ethanol pretreatment specifically increased ALDH2 activity, which then suppressed lipid peroxidation by promoting the detoxification of Malondialdehyde (MDA) and 4-hydroxynonenal (HNE). CONCLUSIONS: Our results provide first line of evidence indicating that antecedent ethanol exposure can provide protection for kidneys against IR-induced injury by enhancing antioxidant capacity and preventing lipid peroxidation. Therefore, ethanol precondition and ectopic ALDH2 activation could be potential therapeutic approaches to prevent renal IR injury relevant to various clinical conditions.