Low dose interleukin-2 selectively expands circulating regulatory T cells but fails to promote liver allograft tolerance in humans.

BACKGROUND & AIMS: CD4+CD25+Foxp3+ regulatory T cells (Tregs) are essential to maintain immunological tolerance and have been shown to promote liver allograft tolerance in both rodents and humans. Low-dose IL-2 (LDIL-2) can expand human endogenous circulating Tregs in vivo, but its role in suppressing antigen-specific responses and promoting Treg trafficking to the sites of inflammation is unknown. Likewise, whether LDIL-2 facilitates the induction of allograft tolerance has not been investigated in humans. METHODS: We conducted a clinical trial in stable liver transplant recipients 2-6 years post-transplant to determine the capacity of LDIL-2 to suppress allospecific immune responses and allow for the complete discontinuation of maintenance immunosuppression (ClinicalTrials.gov NCT02949492). One month after LDIL-2 was initiated, those exhibiting at least a 2-fold increase in circulating Tregs gradually discontinued immunosuppression over a 4-month period while continuing LDIL-2 for a total treatment duration of 6 months. RESULTS: All participants achieved a marked and sustained increase in circulating Tregs. However, this was not associated with the preferential expansion of donor-reactive Tregs and did not promote the accumulation of intrahepatic Tregs. Furthermore, LDIL-2 induced a marked IFNγ-orchestrated transcriptional response in the liver even before immunosuppression weaning was initiated. The trial was terminated after the first 6 participants failed to reach the primary endpoint owing to rejection requiring reinstitution of immunosuppression. CONCLUSIONS: The expansion of circulating Tregs in response to LDIL-2 is not sufficient to control alloimmunity and to promote liver allograft tolerance, due, at least in part, to off-target effects that increase liver immunogenicity. Our trial provides unique insight into the mechanisms of action of immunomodulatory therapies such as LDIL-2 and their limitations in promoting alloantigen-specific effects and immunological tolerance. CLINICAL TRIALS REGISTRATION: The study is registered at ClinicalTrials.gov (NCT02949492). IMPACT AND IMPLICATIONS: The administration of low-dose IL-2 is an effective way of increasing the number of circulating regulatory T cells (Tregs), an immunosuppressive lymphocyte subset that is key for the establishment of immunological tolerance, but its use to promote allograft tolerance in the setting of clinical liver transplantation had not been explored before. In liver transplant recipients on tacrolimus monotherapy, low-dose IL-2 effectively expanded circulating Tregs but did not increase the number of Tregs with donor specificity, nor did it promote their trafficking to the transplanted liver. Low-dose IL-2 did not facilitate the discontinuation of tacrolimus and elicited, as an off-target effect, an IFNγ-orchestrated inflammatory response in the liver that resembled T cell-mediated rejection. These results, supporting an unexpected role for IL-2 in regulating the immunogenicity of the liver, highlight the need to carefully evaluate systemic immunoregulatory strategies with investigations that are not restricted to the blood compartment and involve target tissues such as the liver.

Applicability, safety, and biological activity of regulatory T cell therapy in liver transplantation.

Regulatory T cells (Tregs) are a lymphocyte subset with intrinsic immunosuppressive properties that can be expanded in large numbers ex vivo and have been shown to prevent allograft rejection and promote tolerance in animal models. To investigate the safety, applicability, and biological activity of autologous Treg adoptive transfer in humans, we conducted an open-label, dose-escalation, Phase I clinical trial in liver transplantation. Patients were enrolled while awaiting liver transplantation or 6-12 months posttransplant. Circulating Tregs were isolated from blood or leukapheresis, expanded under good manufacturing practices (GMP) conditions, and administered intravenously at either 0.5-1 million Tregs/kg or 3-4.5 million Tregs/kg. The primary endpoint was the rate of dose- limiting toxicities occurring within 4 weeks of infusion. The applicability of the clinical protocol was poor unless patient recruitment was deferred until 6-12 months posttransplant. Thus, only 3 of the 17 patients who consented while awaiting liver transplantation were dosed. In contrast, all six patients who consented 6-12 months posttransplant received the cell infusion. Treg transfer was safe, transiently increased the pool of circulating Tregs and reduced anti-donor T cell responses. Our study opens the door to employing Treg immunotherapy to facilitate the reduction or complete discontinuation of immunosuppression following liver transplantation.

Entecavir or tenofovir monotherapy prevents HBV recurrence in liver transplant recipients: A 5-year follow-up study after hepatitis B immunoglobulin withdrawal.

BACKGROUND: Recent data suggest that oral third-generation nucleos(t)ide analogs (NA) monoprophylaxis following hepatitis B immunoglobulin (HBIg) withdrawal may be effective to prevent HBV reinfection after liver transplantation (LT). PATIENTS AND METHODS: Between 01/2010 and 03/2012, all HBV monoinfected and HBV/HDV co-infected LT patients followed in our centre withdrew HBIg ±â€¯NA and were commenced on either ETV or TDF as monotherapy. RESULTS: Seventy-seven patients were included in the study (55% TDF, 45% ETV). Group A comprised 69 HBV monoinfected patients and Group B 8 HBV/HDV co-infected patients. After HBIg withdrawal, Groups A and B patients were followed for 69 (range 13-83) months and 61 (range 31-78) months, respectively. No Group B patients had HBsAg or HBV DNA recurrence, while 6 (9%) Group A patients became HBsAg-positive after a median of 18 (range 1-40) months. The cumulative 5-year incidence of HBsAg recurrence was 9%. All 6 patients demonstrated undetectable HBV-DNA levels and stable graft function during 30 months of additional follow-up. In 3/6 patients, seroconversion was transitory, while the remaining 3 showed HBsAg levels <0.13 IU/mL over the entire period of observation. Pre-LT HCC emerged as the strongest predictor of HBsAg recurrence. CONCLUSION: HBIG can be safely discontinued in HBsAgpositive LT recipients and replaced by ETV or TDF monotherapy.

Successful pregnancy outcomes following liver transplantation is predicted by renal function.

Liver transplantation (LT) is a successful treatment for both acute liver failure and end-stage liver disease. The number of women of reproductive age undergoing LT is increasing. Pregnancy outcomes are favorable, but there is still a lack of prognostic markers. We aimed to identify factors predictive of adverse pregnancy outcomes in LT recipients. An analysis of all pregnancies occurring in LT recipients from 1989 to 2016 at King's College Hospital was performed. Clinical data of 162 conceptions in 93 women were reviewed. Descriptive and regression analyses were done to examine associations between laboratory markers and hepatological scores with pregnancy outcomes of live birth and preterm birth. Median age at LT was 23 years (range, 1-41 years), with a median age at conception of 30 years (range, 18-47 years). The live birth rate was 75% (n = 121). Of live births, 35% (n = 39/110 available) were delivered preterm. Preconception creatinine levels were higher in patients who had a preterm birth (85 versus 74 µmol/L; P = 0.008), with a preconception estimated glomerular filtration rate (eGFR) <90 mL/minute significantly associated with preterm delivery (P = 0.04). Progressive decline in eGFR predicted outcome, with gestational length declining with increasing chronic kidney disease (CKD) stage: CKD 0-1 = 39 weeks (median), CKD 2 = 37 weeks, and CKD 3 = 35 weeks. The risk of preterm birth was greatest in women with an eGFR <60 mL/minute (P = 0.004). Moreover, hypertension-related complications during pregnancy, such as gestational hypertension, preeclampsia, or eclampsia, were also associated with prematurity (P = 0.01). Women taking steroid-based immunosuppression had an increased risk of infection during pregnancy or postpartum (15% versus 4%; P = 0.02). In conclusion, although the majority of women have a successful pregnancy outcome after LT, preconception renal function predicts pregnancy outcome and steroids increase risk of infection during pregnancy or postpartum. Liver Transplantation 24 606-615 2018 AASLD.

Subacute liver failure secondary to black cohosh leading to liver transplantation.

The use of herbal medications is increasing significantly in the UK and there is a perception that herbal preparations are without adverse effects. This case report highlights the potential risks of black cohosh, which is one of the most commonly used herbal products. This is a case report of a 60-year-old Caucasian lady who presented with subacute liver failure secondary to taking black cohosh. This was further confirmed by liver biopsy and she subsequently deteriorated and underwent liver transplantation. Available evidence supports an association between black cohosh and risk of hepatotoxicity. In current literature, there have only been four previously reported cases of hepatotoxicity associated with black cohosh, which required liver transplantation. We submit that our patient represents the fifth case. We recommend that patients taking this supplement should have close monitoring of their hepatic function, especially in the presence of other risk factors.