Comparison of Three Cellular Assays to Predict the Course of CMV Infection in Liver Transplant Recipients.

To estimate protection from cytomegalovirus (CMV) replication after solid organ transplantation, CMV serology has been considered insufficient and thus CMV immunity is increasingly assessed by cellular in vitro methods. We compared two commercially available IFN-γ ELISpot assays (T-Track CMV and T-SPOT.CMV) and an IFN-γ ELISA (QuantiFERON-CMV). Currently, there is no study comparing these three assays. The assays were performed in 56 liver transplant recipients at the end of antiviral prophylaxis and one month thereafter. In CMV high- or intermediate-risk patients the two ELISpot assays showed significant correlation (p < 0.0001, r > 0.6) but the correlation of the ELISpot assays with QuantiFERON-CMV was weaker. Results of both ELISpot assays were similarly predictive of protection from CMV-DNAemia ≥500 copies/mL [CMV pp65 T-SPOT.CMV at the end of prophylaxis: area under curve (AUC) = 0.744, cut-off 142 spot forming units (SFU), sensitivity set to 100%, specificity 46%; CMV IE-1 T-Track CMV at month 1: AUC = 0.762, cut-off 3.5 SFU, sensitivity set to 100%, specificity 59%]. The QuantiFERON-CMV assay was inferior, reaching a specificity of 23% when setting the sensitivity to 100%. In conclusion, both CMV-specific ELISpot assays appear suitable to assess protection from CMV infection/reactivation in liver transplant recipients.

Primary sclerosing cholangitis as an independent risk factor for cytomegalovirus infection after liver transplant.

BACKGROUND: Cytomegalovirus (CMV) infection is one of the most common infectious complications after solid organ transplant; it is associated with morbidity and mortality and with many direct and indirect effects. However, monitoring and therapeutic procedures are very heterogeneous across treatment centers. Additionally, factors that place patients at risk of CMV infection are poorly defined. METHODS: Clinical and demographic data from 833 LT recipients and their donors were retrospectively analyzed. Univariate and multivariate analysis were applied. CMV infection was detected by quantitative nucleic acid testing with a lower limit of detection of 40 IU/mL. RESULTS: In total, 192 of 833 patients (23%) experienced at least one episode of CMV infection after LT; CMV infection occurred to a large extent during the first year after transplant (70%). Multivariate analysis demonstrated that CMV donor-recipient risk constellation (OR 2.05, 95% CI) and primary sclerosing cholangitis (PSC) before LT (OR 3.76, 95% CI) are independent risk factors for CMV infection after LT. CONCLUSION: Patients with high-risk serostatus, PSC, or both should be monitored more thoroughly and should receive prolonged prophylaxis against CMV infection.

Safety and efficacy of tenofovir alafenamide in liver transplant recipients: A single center experience.

BACKGROUND: Tenofovir disoproxil fumarate (TDF) is frequently used for treatment of and prophylaxis against reactivation of hepatitis B virus (HBV) after liver transplant (LT). Because TDF can lead to renal impairment and a decrease in bone mineral density (BMD), the prodrug tenofovir alafenamide (TAF) may be considered a viable alternative with fewer adverse effects. Only limited information is available about the use of TAF for LT recipients. We report a European single-center experience with TAF as treatment for LT patients. METHODS: This retrospective analysis involved 29 LT recipients receiving standard immunosuppressants (mainly calcineurin inhibitors). Demographic and clinical data were documented at baseline upon switch to TAF and at various time points thereafter. RESULTS: None of the patients experienced HBV reactivation after the switch to TAF. Liver and renal function remained stable. Drug levels of immunosuppressive agents did not change significantly after the switch. After 1 year, 22 patients were still taking TAF; two patients had been lost to follow-up; one patient had died; and four patients had discontinued therapy because of TAF-related adverse effects. No serious adverse effects were reported. CONCLUSIONS: Tenofovir alafenamide exhibits high antiviral efficacy and a good safety profile for LT recipients. Still, the safety and tolerability of TAF for organ transplant patients should be evaluated in larger cohorts.

Current Challenges in the Post-Transplant Care of Liver Transplant Recipients in Germany.

Improving long-term patient and graft survival after liver transplantation (LT) remains a major challenge. Compared to the early phase after LT, long-term morbidity and mortality of the recipients not only depends on complications immediately related to the graft function, infections, or rejection, but also on medical factors such as de novo malignancies, metabolic disorders (e.g., new-onset diabetes, osteoporosis), psychiatric conditions (e.g., anxiety, depression), renal failure, and cardiovascular diseases. While a comprehensive post-transplant care at the LT center and the connected regional networks may improve outcome, there is currently no generally accepted standard to the post-transplant management of LT recipients in Germany. We therefore described the structure and standards of post-LT care by conducting a survey at 12 German LT centers including transplant hepatologists and surgeons. Aftercare structures and form of cost reimbursement considerably varied between LT centers across Germany. Further discussions and studies are required to define optimal structure and content of post-LT care systems, aiming at improving the long-term outcomes of LT recipients.

HLA class II donor specific antibodies are associated with graft cirrhosis after liver transplant independent of the mean fluorescence intensity level.

BACKGROUND: The importance of donor-specific antibodies (DSA) after liver transplantation (LT) for graft and patient survival is an ongoing controversy. So far it has not been elucidated when and in how far DSA are harmful for graft and patient survival. Therefore, we had the aim to investigate the association of DSA with complications after LT. METHODS: Data of 430 LT recipients were collected and statistically analyzed. Detection of HLA antibodies (Ab) was performed by Luminex assay. RESULTS: DSA were detected in 81 patients (18.8%). These were mainly HLA class II Ab (81.5%). HLA class II Ab show a higher MFI (median: 5.300) compared to HLA class I Ab (median: 2.300). There is no association between MFI levels and development of complications after LT. However, cirrhosis occurred significantly more often in DSA positive patients (18%) than in patients without detectable DSA (9%, P = 0.027). All DSA positive patients with cirrhosis of the graft showed HLA class II antibodies (OR: 3.028; 95% CI: 1.51-6.075; P = 0.002). CONCLUSION: Occurrence of HLA class II DSA after LT is associated with graft cirrhosis and may indicate a higher risk to develop graft damage independent on MFI and requires an individualized risk management.

Prevention and Management of CMV Infections after Liver Transplantation: Current Practice in German Transplant Centers.

Human cytomegalovirus (CMV) remains a major cause of mortality and morbidity in human liver transplant recipients. Anti-CMV therapeutics can be used to prevent or treat CMV in liver transplant recipients, but their toxicity needs to be balanced against the benefits. The choice of prevention strategy (prophylaxis or preemptive treatment) depends on the donor/recipient sero-status but may vary between institutions. We conducted a series of consultations and roundtable discussions with German liver transplant center representatives. Based on 20 out of 22 centers, we herein summarize the current approaches to CMV prevention and treatment in the context of liver transplantation in Germany. In 90% of centers, transient prophylaxis with ganciclovir or valganciclovir was standard of care in high-risk (donor CMV positive, recipient CMV naive) settings, while preemptive therapy (based on CMV viremia detected during (bi) weekly PCR testing for circulating CMV-DNA) was preferred in moderate- and low-risk settings. Duration of prophylaxis or intense surveillance was 3-6 months. In the case of CMV infection, immunosuppression was adapted. In most centers, antiviral treatment was initiated based on PCR results (median threshold value of 1000 copies/mL) with or without symptoms. Therefore, German transplant centers report similar approaches to the prevention and management of CMV infection in liver transplantation.

Dynamics of liver stiffness by transient elastography in patients with chronic hepatitis C virus infection receiving direct-acting antiviral therapy-Results from the German Hepatitis C-Registry.

The impact of direct-acting antiviral (DAA) therapies on fibrosis regression remains uncertain. In the current study, we prospectively evaluated dynamics of liver stiffness by transient elastography (TE) in patients with chronic HCV infection receiving DAA-based treatment. Patients (260) were enrolled in the German Hepatitis C-Registry (DHC-R), a national multicentre real-world cohort. Liver stiffness (LS) was assessed at baseline, end of treatment (EOT) and 24 weeks after EOT (FU24) by TE. Biochemical, virological and clinical data were obtained in parallel. In patients with SVR, there was a significant improvement of LS between baseline (median [range], 8.6 [1.7-73.5] kPa) and FU24 (7.9 [1.7-75 kPa]; P < .0001) as well as between EOT (8.4 [1.7-73.5 kPa]) and FU24 [P < .0001]. Stratified by fibrosis stage, patients classified into F4 had higher magnitude of LS reduction between BL (median [range], 25.1 [13.5-73.5] kPa) and FU24 (21.5 [3.1-75] kPa; P = .002) compared to those with F2-F3 (8.9 [7.1-12.4] kPa and 8.8 [4.2-29.1]; P = .060) or F0-F1 (5.3 [1.7-7] kPa and 5.2 [1.7-7.7]; P = .064). In cirrhotic patients, low platelets were significantly associated with lack of liver stiffness improvement, both at EOT (P = .018) and at FU24 (P = .012). LS significantly correlated with ALT (r = .371), AST (r = .552), platelets (r = -.499), GGT (r = .250), bilirubin (r = .230), APRI score (r = .512), FIB-4 score (r = .517) and FORNS index (r = .562); P < .0001. Liver elastography improved significantly in our real-world cohort after DAA-based therapy. As LS correlates similarly with transaminase levels and serum fibrosis markers, it might reflect both reduction of necroinflammation and fibrosis regression.

Real-World Administration of Once-Daily MeltDose® Prolonged-Release Tacrolimus (LCPT) Allows for Dose Reduction of Tacrolimus and Stabilizes Graft Function Following Liver Transplantation.

The calcineurin inhibitor tacrolimus is included in most immunosuppressive protocols after liver transplantation. This retrospective, observational 24-month study investigated the tolerability of once-daily MeltDose® prolonged-release tacrolimus (LCPT) after switching from twice-daily immediate-release tacrolimus (IR-Tac) in a real-world cohort of 150 patients with previous liver transplantation. No graft rejection or new safety signals were observed. Only 7.3% of patients discontinued LCPT due to side effects. In the overall patient population, median liver transaminases, total cholesterol, triglycerides, glucose, and HbA1c remained constant after switching to LCPT. Total cholesterol significantly decreased (p ≤ 0.002) in patients with initially elevated levels (>200 mg/dL). A total of 71.8% of 96 patients maintained a glomerular filtration rate >60 mL/min/1.73 m2 throughout the study, while 44.7% of patients were classified as fast metabolizers and 55.3% as slow metabolizers. Median daily tacrolimus dose could be reduced by 50% in fast metabolizers and by 30% in slow metabolizers, while trough levels were maintained in the target range (4-6 ng/mL). In conclusion, our observational study confirmed previous evidence of good overall tolerability and a favorable outcome for the patients after switching from IR-Tac to LCPT after liver transplantation.

Successful early sofosbuvir-based antiviral treatment after transplantation of kidneys from HCV-viremic donors into HCV-negative recipients.

BACKGROUND: Transplanting kidneys from deceased donors with hepatitis C virus (HCV) viremia has been controversial for some time. Direct-acting antiviral agents have been shown to be highly effective in treating HCV infection. We report our experience with transplanting kidneys from HCV-positive donors with detectable viremia into HCV-negative recipients, followed by early treatment with a sofosbuvir-based antiviral regimen. METHODS: Data were collected from seven HCV-negative recipients receiving kidneys from five deceased HCV-viremic donors. Before transplantation, all intentional transplanted recipients had given informed consent regarding the acceptance of an HCV-viremic kidney. Recipients were closely monitored after transplant with measurements of HCV viremia, liver and renal function, and trough levels of immunosuppressive drugs. RESULTS: Four donors were infected with HCV genotype 1; the other with HCV genotype 3a. HCV viremia was detectable in all seven renal transplant recipients within 3 days after transplant. After determination of HCV genotype, antiviral treatment with a sofosbuvir-based regimen (sofosbuvir/ledipasvir, n = 4; sofosbuvir/velpatasvir, n = 3) was initiated within a median of 7 days after transplantation and was continued for 8 to 12 weeks. For all recipients, viral load was below the level of detection at the end of treatment, and all exhibited a sustained virologic response 12 weeks later. All recipients exhibited normal liver enzyme activity at the end of treatment. Renal allograft function and trough levels of tacrolimus remained stable. CONCLUSIONS: Early administration of a sofosbuvir-based regimen to HCV-negative recipients of kidneys from HCV-viremic donors is feasible and safe. The definition of an optimal therapeutic approach warrants further investigation.

Improving the vaccination status of liver transplant patients: Effectiveness of personally addressing patients and written recommendations to family physicians after 3 years.

BACKGROUND: After documenting insufficient vaccinations in 444 liver transplant (LT) patients, we investigated the effects of a combined strategy (addressing both patients and primary care physicians) on immunization prevalences after a 3-year follow-up. METHODS: The primary care physicians of all adult LT patients from a university center received a written recommendation addressing immunization needs. Patients were asked for their vaccination documents by phone. Changes in immunization rates for vaccine-preventable diseases after the intervention were calculated based on patients' immunization documents from 2014-2016. RESULTS: The study cohort consisted of 401 patients. Prevalence rates for all vaccinations improved during the intervention period compared to the baseline study: tetanus from 88.3% to 92.8%, diphtheria from 80.0% to 89.0%, hepatitis A from 50.1% to 60.8%, hepatitis B from 66.3% to 77.1%, and pneumococci from 62.8% to 76.3%. The influenza vaccination rate improved, but remained at a low level before (2010:13%, 2011:11.5%, 2012:19%) and during the intervention (2014:27.4%, 2015:24.4%, 2016:23.2%). Despite these vaccinations, the prevalence rates of the quality indicators standard vaccinations completed (2013:17.2%; 2016:21.2%), indicated vaccinations completed (2013:2.7%, 2016:4.5%), and all vaccinations completed (2013:1%; 2016 1.5%) improved only slightly. CONCLUSIONS: Our results demonstrated that intensified communication by written information to the primary care physician and phone calls to the patients improved the number of vaccinations. Nonetheless, a potential for further improvement persists, especially with regard to annual influenza vaccinations.

SNPs Within the MTOR Gene Are Associated With an Increased Risk of Developing De Novo Diabetes Mellitus Following the Administration of Everolimus in Liver Transplant Recipients.

BACKGROUND: The impact of immunosuppressive drugs in patients following liver transplantation (LT) is very individual. Despite the multiple beneficial effects of the mammalian target of rapamycin (mTOR) inhibitor everolimus (EVR) in LT recipients, some patients do not benefit from EVR administration. We investigated whether the presence of common single-nucleotide polymorphisms (SNPs) in the mTOR gene are predictive for adverse events following the introduction of EVR after LT. MATERIALS AND METHODS: The feasibility and efficacy of EVR in 127 liver transplant recipients who were converted to EVR-based immunosuppression was documented retrospectively. Blood samples of these patients were analyzed for the occurrence of 4 SNPs in the mTOR promoter region (mTOR3099/rs2295079 C>G, mTOR3162/rs2295080 A>C) and the mTOR 3' untranslated regio (mTOR8167/rs12139042 C>T, mTOR8600/rs2536 A>G); the specific allele variants were also associated with the incidence of adverse events (AEs). RESULTS: Of all patients, 21 (16.5%) did not tolerate the medication and had to discontinue. Of those patients who continued, 37% developed signs of reduced tolerance within the first 6 months, resolving after 12 months. When the cohort was divided according to genotype and allele frequency, patients with the mTOR3162/rs2295080 CC variant had a significantly higher risk (odds ratio = 5.89; 95% confidence interval = 1.48-23.40; P = .012) of developing new-onset diabetes mellitus following EVR treatment than AA or AC genotype carriers. CONCLUSION: Our results suggest that the SNP mTOR3162/rs2295080 CC genotype is associated with the development of new-onset diabetes mellitus following EVR treatment.

Promyelocytic leukemia protein deficiency leads to spontaneous formation of liver tumors in hepatitis C virus transgenic mice.

Persistent infection with hepatitis C virus (HCV) is a known risk factor for the development of hepatocellular carcinoma (HCC). The lack of the tumor suppressor promyelocytic leukemia protein (PML) in combination with HCV fosters hepatocarcinogenesis via induction of HCC using diethylnitrosamine (DEN) in a rodent model. However, the spontaneous development of malignant lesions in PML-deficient mice with an HCV-transgene (HCVtg ) has not been investigated thus far. We crossed PML-deficient mice with HCV transgene expressing mice and observed the animals for a period of 12 months. Livers were examined macroscopically and histologically. Gene expression analysis was performed on these samples, and compared with expression of selected genes in human samples of patients undergoing liver transplantation for HCC. In vitro studies were performed in order to analyze the selected pathways. Genetic depletion of PML in combination with HCVtg coincided with an increased hepatocyte proliferation, resulting in development of HCCs in 40% of the PML-deficient livers. No tumor development was observed in mice with either the PML-knockout (PML-/- ) or HCVtg alone. Gene expression profiling uncovered pathways involved in cell proliferation, such as NLRP12 and RASFF6. These findings were verified in samples from human livers of patients undergoing liver transplantation for HCC. Further in vitro studies confirmed that lack of PML, NLRP12, and RASFF6 leads to increased cell proliferation. The lack of PML in combination with HCV is associated with increased cell proliferation, fostering tumor development in the liver. Our data demonstrate that PML acts as an important tumor suppressor in HCV-dependent liver pathology.

The Effect of Immunosuppression on Coagulation After Liver Transplantation.

Everolimus (EVR) is a mammalian target of rapamycin (mTOR) inhibitor commonly used for immunosuppression (IS) after liver transplantation (LT). However, there are concerns about whether mTOR inhibitors may move the hemostatic balance toward a higher likelihood of thrombosis. The present study aimed to investigate potential coagulation disorders after the administration of EVR. We evaluated 54 patients after conversion to an EVR-based IS regimen (n = 26) and compared those patients with patients who were switched to extended-release tacrolimus (TAC) but had never received EVR (n = 28). At baseline and again at 1 month and 6 months after conversion, we measured international normalized ratio, activated partial thromboplastin time, and anticoagulation and fibrinolysis factors, and we performed rotational thromboelastometry (ROTEM). Data were analyzed with a Mann-Whitney U test, a repeated-measure analysis of variance, and a Fisher's exact test. Statistical significance was set at the level of P ≤ 0.05. Plasma levels of von Willebrand factor, fibrinogen, and factor VIII were significantly higher than baseline levels at 1 month and 6 months after conversion of IS to EVR (P < 0.001); plasma levels of protein C, protein S, and plasminogen also increased significantly (P < 0.001). ROTEM confirmed a significant increase in maximum clot firmness in EXTEM, INTEM, and FIBTEM assays (P < 0.001). In all assays, maximum lysis was significantly lower than baseline levels at 1 month and 6 months after conversion to EVR. Patients converted to IS with extended-release TAC exhibited no significant changes in coagulation variables. Retrospective analysis showed a significantly higher incidence of thromboembolic complications among patients treated with EVR-based IS than among those treated with extended-release TAC (P < 0.01). In conclusion, the administration of EVR after LT seems to modify hemostasis to a procoagulant state. Thrombophilia screening before conversion may determine which patients will benefit from conversion to EVR-based IS.

Treatment With Grazoprevir/Elbasvir for Renal Transplant Recipients With Chronic Hepatitis C Virus Infection and Impaired Allograft Function.

BACKGROUND: Direct-acing antiviral agents are highly efficient treatment options for chronic hepatitis C virus (HCV) infection after renal allograft transplantation. Treatment options for patients with impaired graft function remain limited. Therefore, we assessed the effectiveness and safety of grazoprevir/elbasvir therapy for patients with chronic HCV infection and impaired renal allograft function. METHODS: Eleven renal allograft recipients with therapy-naïve HCV genotype (GT) 1a, 1b, or 4 were treated with the fixed-dose combination of elbasvir/grazoprevir without ribavirin for 12 weeks. All recipients exhibited impaired graft function with an average glomerular filtration rate lower than 30 mL/min per 1.73 m2. Clinical data were retrospectively reviewed for renal and liver function parameters. Patients were closely monitored for trough levels of immunosuppressive agents, viral load, laboratory values, and potential adverse effects. RESULTS: Seven (64%) patients exhibited a rapid virologic response within 4 weeks (HCV GT1a, n = 2; HCV GT1b, n = 5). The other 4 patients exhibited a virologic response within 8 weeks (HCV GT1b, n = 3; HCV GT 4, n = 1). All patients exhibited a sustained virologic response at week 12 after the end of treatment. Clinical measures of liver function improved substantially for all patients. Few adverse effects were reported. Impaired renal allograft function and proteinuria remained stable. For most patients, only moderate adjustments to the tacrolimus dosage were necessary for maintaining sufficient trough levels. CONCLUSIONS: This treatment appears to be safe and effective for renal transplant recipients with impaired allograft function and is a promising treatment option for eradicating HCV infection in this patient population.

Efficacy of IgM-enriched Immunoglobulin for Vasopressor-resistant Vasoplegic Shock After Liver Transplantation.

BACKGROUND: Vasoplegia is a clinical condition typically manifested by cardiovascular instability unresponsive to the usual doses of inotropes or vasopressors. It can occur in a variety of clinical settings including liver transplantation (LT). Immunoglobulins have been used to treat sepsis-related vasoplegia. We performed a retrospective study to evaluate the efficacy of IgM-enriched immunoglobulin (IgMIg) on 30-day mortality and its ability to reverse vasoplegia in patients undergoing LT. METHODS: Between May 2013 and November 2017, 473 LT were performed at our institution. We identified 21 patients who received IgMIg for 3 days to treat vasoplegia. Patients included in the study met the criteria for having vasoplegia and required noradrenaline administration greater than 1 µg·kg·min for more than 24 hours to maintain a mean arterial pressure of 70 mm Hg or greater. Procalcitonin and interleukin-6 (IL-6) levels were used as surrogate markers for inflammation and were measured at the beginning and end of IgM treatment. RESULTS: After IgMIg administration, median noradrenaline infusion rates could be significantly reduced from 1.6 µg·kg·min (1.3-2 µg·kg·min) to 0.16 µg·kg·min (0.08-0.34 µg·kg·min) (P < 0.001). In addition, after treatment, procalcitonin levels decreased significantly from 44 ng/mL (24-158) to 26.1 ng/mL (10.9-48.7) (P < 0.001) and IL-6 levels decreased significantly from 63 pg/mL (29-102) to 20 pg/mL (11-20) (P < 0.001). Thirty-day morality was 14.3%. CONCLUSIONS: The administration of IgMIg in patients with vasoplegia after LT is associated with a return of hemodynamic stability. Despite a predicted mortality of over 90% by Sepsis-Related Organ Failure Assessment score, the mortality rate of patients receiving IgMIg in our study was less than 20%.

Recurrence of Hepatitis B Infection in Liver Transplant Patients Receiving Long-Term Hepatitis B Immunoglobulin Prophylaxis.

BACKGROUND Long-term real-world data are relatively sparse regarding recurrence of chronic hepatitis B virus (HBV) infection after liver transplantation using hepatitis B immunoglobulin (HBIg) and nucleos(t)ide analogue (NUC) prophylaxis. MATERIAL AND METHODS Data from 371 adults transplanted for HBV-related disease at 20 European centers and given HBIg for ³12 months ± NUC therapy were analyzed retrospectively. RESULTS HBIg comprised Hepatect® (iv HBIgB; n=299), subcutaneous Zutectra® (sc HBIg, n=236), and other HBIg preparations (n=130); 93.5% received NUC therapy. Mean follow-up was 6.8±3.5 years. The primary efficacy variable, freedom from HBV recurrence, occurred in 95.7% of patients (95% CI [93.1%, 97.5%]). The observed incidence of recurrence was 16/371 (4.3%) (annual rate 0.65%); 5/16 patients with recurrence had discontinued HBIg and 7/16 had anti-HBs <100 IU/l. Excluding these 7 patients, the HBV recurrence rate was 2.4%. The recurrence rate while on HBIg therapy was 1 per 2069 months. In patients who discontinued HBIg, risk of HBV recurrence versus sc HBIg users was increased by 5.2-fold (1 per 1 603 versus 1 per 8379 treatment months). The annual rate of HBV-related hepatocellular carcinoma (HCC) recurrence was 1.7%. CONCLUSIONS These results support the long-term use of HBIg with NUC therapy as an effective management strategy to minimize risk of HBV recurrence and virus-related complications after liver transplantation.

The influence of immunosuppressants on direct-acting antiviral therapy is dependent on the hepatitis C virus genotype.

BACKGROUND: Direct-acting antivirals (DAAs) have substantially increased sustained virological response rates after liver transplantation, with improved tolerance compared to interferon-based therapy. The influence of immunosuppressive agents on the efficacy of DAAs has not been clarified. METHODS: Subgenomic hepatitis C virus (HCV) replicons for genotype (GT) 1b, 2b, 3a, and 4a were treated with the mammalian target of rapamycin (mTOR) inhibitors everolimus and sirolimus or with the calcineurin inhibitors (CNIs) cyclosporine or tacrolimus, either alone or in combination with selected DAAs. Cell proliferation-related effects were excluded with MTT assays. HCV replication activity was quantified by quantitative real-time polymerase chain reaction or luciferase assay. RESULTS: Addition of either mTOR inhibitor to the DAA daclatasvir (DAC) resulted in a 30% increase in antiviral activity compared to DAC alone for HCV GT2a, GT3a, and GT4a (all P ≤ .01). Similar results were obtained using sofosbuvir and ledipasvir. In contrast, addition of either mTOR inhibitor to DAC induced a 30% reduction in antiviral activity in GT1b cells (P ≤ .01 vs DAC alone). Neither CNI affects the antiviral activity of the DAAs in any HCV GT. CONCLUSION: For patients with HCV GT2a, GT3a, or GT4a infection, mTOR-based immunosuppressive therapy may be beneficial. CNI-based therapy may be more efficacious in GT1b patients, as mTOR inhibitors seem to impair antiviral efficacy of DAAs in HCV GT1b infection.