Successful use of gentamycin as an antibiotic prophylaxis regimen to reduce the rate of healthcare-associated infections after renal transplantation

At our institution, we observed an increase in the incidence of healthcare-associated infections (HAI) due to Gram-negative bacilli, including three cases of carbapenem-resistant Klebsiella pneumoniae, among patients who underwent renal transplantation. In addition to strengthening infection control measures, we chose to add gentamycin to the antibiotic prophylaxis regimen of patients undergoing renal transplantation. We assessed the number of HAI occurring within 30 days of renal transplantation during two time periods: (1) the pre-intervention period, between September 2009 and June 2010, and (2) the post-intervention period, between July 2010 and April 2011. The intervention consisted of the addition of gentamycin to the surgical antibiotic prophylaxis regimen. The percentage of patients with HAIs was 31% lower during the post-intervention period (p = 0.03), with the greatest reductions observed for urinary tract infections (p = 0.024). Carbapenem-resistant K. pneumoniae was not isolated during this period. The investigated patients did not exhibit worsening renal function. Further studies are needed to assess antibiotic prophylaxis in renal transplantation patients at institutions where there is a high prevalence of multidrug-resistant Gram-negative bacteria.

Molecular characterization of hepatocellular adenomas developed in patients with glycogen storage disease type I

BACKGROUND & AIMS

Hepatocellular adenomas (HCA) are benign liver tumors mainly related to oral contraception and classified into 4 molecular subgroups: inflammatory (IHCA), HNF1A-inactivated (H-HCA), β-catenin-activated (bHCA) or unclassified (UHCA). Glycogen storage disease type I (GSD) is a rare hereditary metabolic disease that predisposes to HCA development. The aim of our study was to characterize the molecular profile of GSD-associated HCA.

METHODS

We characterized a series of 25 HCAs developed in 15 patients with GSD by gene expression and DNA sequence of HNF1A, CTNNB1, IL6ST, GNAS, and STAT3 genes. Moreover, we searched for glycolysis, gluconeogenesis, and fatty acid synthesis alterations in GSD non-tumor livers and compared our results to those observed in a series of sporadic H-HCA and various non-GSD liver samples.

RESULTS

GSD adenomas were classified as IHCA (52%) mutated for IL6ST or GNAS, bHCA (28%) or UHCA (20%). In contrast, no HNF1A inactivation was observed, showing a different molecular subtype distribution in GSD-associated HCA from that observed in sporadic HCA (p = 0.0008). In non-tumor GSD liver samples, we identified glycolysis and fatty acid synthesis activation with gluconeogenesis repression. Interestingly, this gene expression profile was similar to that observed in sporadic H-HCA.

CONCLUSIONS

Our study showed a particular molecular profile in GSD-related HCA characterized by a lack of HNF1A inactivation. This exclusion could be explained by similar metabolic defects observed with HNF1A inactivation and glucose-6-phosphatase deficiency. Inversely, the high frequency of β-catenin mutations could be related to the increased frequency of malignant transformation in hepatocellular carcinoma.

Response to treatment in Brazilian patients with chronic hepatitis C is associated with a single-nucleotide polymorphism near the interleukin-28B gene

A single-nucleotide polymorphism (SNP) upstream of interleukin (IL)28B was recently identified as an important predictor of the outcome of chronic hepatitis C patients treated with pegylated interferon plus ribavirin (PEG-IFN/RBV). The aim of this study was to investigate the association between the IL28B gene polymorphism (rs12979860) and virological response in chronic hepatitis C patients. Brazilian patients (n = 263) who were infected with hepatitis C virus (HCV) genotype 1 and were receiving PEG-IFN/RBV were genotyped. Early virological response (EVR) (12 weeks), end-of-treatment response (EOTR) (48 weeks), sustained virological response (SVR) (72 weeks) and relapse were evaluated using conventional and quantitative polymerase chain reaction (PCR) assays. The frequency of the C allele in the population was 39%. Overall, 43% of patients experienced SVR. The IL28B CC genotype was significantly associated with higher treatment response rates and a lower relapse rate compared to the other genotypes [84% vs. 58% EVR, 92% vs. 63% EOTR, 76% vs. 38% SVR and 17% vs. 40% relapse rate in CC vs. other genotypes (CT and TT), respectively]. Thus, the IL28B genotype appears to be a strong predictor of SVR following PEG-IFN/RBV therapy in treatment-naïve Brazilian patients infected with HCV genotype 1. This study, together with similar research examining other SNPs, should help to define adequate protocols for the treatment of patients infected with HCV genotype 1, especially those with a poor prognosis.

Clinical operational tolerance in liver transplantation: state-of-the-art perspective and future prospects

BACKGROUND

Liver transplantation is the definite treatment for end-stage liver diseases with satisfactory results. However, untoward effects of life-long immunosuppression prevent the development of alternative strategies to achieve better long-term outcome. Achieving clinical operational tolerance is the ultimate goal.

DATA SOURCES

A PubMed and Google Scholar search using terms: "immune tolerance", "liver transplantation", "clinical trial", "operational tolerance" and "immunosuppression withdrawal" was performed, and relevant articles published in English in the past decade were reviewed. Full-text publications relevant to the field were selected and relevant articles from reference lists were also included. Priority was given to those articles which are relevant to the review.

RESULTS

Because of the inherent tolerogenic property, around 20%-30% of liver transplantation recipients develop spontaneous operational tolerance after immunosuppression withdrawal, and the percentage may be even higher in pediatric living donor liver transplantation recipients. Several natural killer and gammadeltaT cell related markers have been identified to be associated with the tolerant state in liver transplantation patients. Despite the progress, clinical operational tolerance is still rare in liver transplantation. Reprogramming the recipient immune system by creating chimerism and regulatory cell therapies is among newer promising means to achieve clinical liver transplantation tolerance in the future.

CONCLUSION

Although clinical operational tolerance is still rare in liver transplantation recipients, ongoing basic research and collaborative clinical trials may help to decipher the mystery of transplantation tolerance and extend the potential benefits of drug withdrawal to an increasing number of patients in a more predictable fashion.

Liposarcoma of the spermatic cord mimicking a left inguinal hernia: a case report and literature review

Liposarcoma of the spermatic cord (LSC) is a rare condition characterized by a painless inguinal or scrotal mass. To our knowledge, only about 200 cases have been previously reported in the literature. These tumors are often mistaken for common scrotal swellings, such as hydroceles and hernias. We present a LSC case in which a definitive diagnosis was obtained upon histological examination. We also provide a literature review of other cases that have been reported.

Living-donor liver transplantation and hepatitis C

Hepatitis-C-virus- (HCV-) related end-stage cirrhosis is the primary indication for liver transplantation in many countries. Unfortunately, however, HCV is not eliminated by transplantation and graft reinfection is universal, resulting in fibrosis, cirrhosis, and finally graft decompression. In areas with low deceased-donor organ availability like Japan, living-donor liver transplantation (LDLT) is similarly indicated for HCV cirrhosis as deceased-donor liver transplantation (DDLT) in Western countries and accepted as an established treatment for HCV-cirrhosis, and the results are equivalent to those of DDLT. To prevent graft failure due to recurrent hepatitis C, antiviral treatment with pegylated-interferon and ribavirin is currently considered the most promising regimen with a sustained viral response rate of around 30% to 35%, although the survival benefit of this regimen remains to be investigated. In contrast to DDLT, many Japanese LDLT centers have reported modified treatment regimens as best efforts to secure first graft, such as aggressive preemptive antiviral treatment, escalation of dosages, and elongation of treatment duration.

Islet transplantation in type 1 diabetes: ongoing challenges, refined procedures, and long-term outcome

Remarkable progress has been made in islet transplantation over a span of 40 years. Once just an experimental curiosity in mice, this therapy has moved forward, and can now provide robust therapy for highly selected patients with type 1 diabetes (T1D), refractory to stabilization by other means. This progress could not have occurred without extensive dynamic international collaboration. Currently, 1,085 patients have undergone islet transplantation at 40 international sites since the Edmonton Protocol was reported in 2000 (752 allografts, 333 autografts), according to the Collaborative Islet Transplant Registry. The long-term results of islet transplantation in selected centers now match registry data of pancreas-alone transplantation, with 6 sites reporting five-year insulin independence rates ≥50%. Islet transplantation has been criticized for the use of multiple donor pancreas organs, but progress has also occurred in single-donor success, with 10 sites reporting increased single-donor engraftment. The next wave of innovative clinical trial interventions will address instant blood-mediated inflammatory reaction (IBMIR), apoptosis, and inflammation, and will translate into further marked improvements in single-donor success. Effective control of auto- and alloimmunity is the key to long-term islet function, and high-resolution cellular and antibody-based assays will add considerable precision to this process. Advances in immunosuppression, with new antibody-based targeting of costimulatory blockade and other T-B cellular signaling, will have further profound impact on the safety record of immunotherapy. Clinical trials will move forward shortly to test out new human stem cell derived islets, and in parallel trials will move forward, testing pig islets for compatibility in patients. Induction of immunological tolerance to self-islet antigens and to allografts is a difficult challenge, but potentially within our grasp.

Glycogenotic hepatocellular carcinoma with glycogen-ground-glass hepatocytes: A heuristically highly relevant phenotype

Glycogenotic hepatocellular carcinoma (HCC) with glycogen-ground-glass hepatocytes has recently been described as an allegedly “novel variant” of HCC, but neither the historical background nor the heuristic relevance of this observation were put in perspective. In the present contribution, the most important findings in animal models and human beings related to the emergence and further evolution of excessively glycogen storing (glycogenotic) hepatocytes with and without ground glass features during neoplastic development have been summarized. Glycogenotic HCCs with glycogen-ground-glass hepatocytes represent highly differentiated neoplasms which contain subpopulations of cells phenotypically resembling those of certain types of preneoplastic hepatic foci and benign hepatocellular neoplasms. It is questionable whether the occurrence of glycogen-ground-glass hepatocytes in a glycogenotic HCC justifies its classification as a specific entity. The typical appearance of ground-glass hepatocytes is due to a hypertrophy of the smooth endoplasmic reticulum, which is usually associated with an excessive storage of glycogen and frequently also with an expression of the hepatitis B surface antigen. Sequential studies in animal models and observations in humans indicate that glycogen-ground-glass hepatocytes are a facultative, integral part of a characteristic cellular sequence commencing with focal hepatic glycogenosis potentially progressing to benign and malignant neoplasms. During this process highly differentiated glycogenotic cells including ground-glass hepatocytes are gradually transformed via various intermediate stages into poorly differentiated glycogen-poor, basophilic (ribosome-rich) cancer cells. Histochemical, microbiochemical, and molecular biochemical studies on focal hepatic glycogenosis and advanced preneoplastic and neoplastic lesions in tissue sections and laser-dissected specimens in rat and mouse models have provided compelling evidence for an early insulinomimetic effect of oncogenic agents, which is followed by a fundamental metabolic switch from gluconeogenesis towards the pentose-phosphate pathway and the Warburg type of glycolysis during progression from preneoplastic hepatic glycogenosis to the highly proliferative malignant phenotype.

Importance of liver biopsy findings in immunosuppression management: biopsy monitoring and working criteria for patients with operational tolerance

Obstacles to morbidity-free long-term survival after liver transplantation (LT) include complications of immunosuppression (IS), recurrence of the original disease and malignancies, and unexplained chronic hepatitis and graft fibrosis. Many programs attempt to minimize chronic exposure to IS by reducing dosages and stopping steroids. A few programs have successfully weaned a highly select group of recipients from all IS without apparent adverse consequences, but long-term follow-up is limited. Patients subjected to adjustments in IS are usually followed by serial liver chemistry tests, which are relatively insensitive methods for detecting allograft damage. Protocol biopsy has largely been abandoned for hepatitis C virus-negative recipients, at least in part because of the inability to integrate routine histopathological findings into a rational clinical management algorithm. Recognizing a need to more precisely categorize and determine the clinical significance of findings in long-term biopsy samples, the Banff Working Group on Liver Allograft Pathology has reviewed the literature, pooled the experience of its members, and proposed working definitions for biopsy changes that (1) are conducive to lowering IS and are compatible with operational tolerance (OT) and (2) raise concern for closer follow-up and perhaps increased IS during or after IS weaning. The establishment of guidelines should help us to standardize analyses of the effects of various treatments and/or weaning protocols and more rigorously categorize patients who are assumed to show OT. Long-term follow-up using standardized criteria will help us to determine the consequences of lowering IS and to define and determine the incidence and robustness of OT in liver allografts.

Targeting the PI3K/AKT/mTOR signaling axis in children with hematologic malignancies

The phosphatidylinositiol 3-kinase (PI3K), AKT, mammalian target of rapamycin (mTOR) signaling pathway (PI3K/AKT/mTOR) is frequently dysregulated in disorders of cell growth and survival, including a number of pediatric hematologic malignancies. The pathway can be abnormally activated in childhood acute lymphoblastic leukemia (ALL), acute myelogenous leukemia (AML), and chronic myelogenous leukemia (CML), as well as in some pediatric lymphomas and lymphoproliferative disorders. Most commonly, this abnormal activation occurs as a consequence of constitutive activation of AKT, providing a compelling rationale to target this pathway in many of these conditions. A variety of agents, beginning with the rapamycin analogue (rapalog) sirolimus, have been used successfully to target this pathway in a number of pediatric hematologic malignancies. Rapalogs demonstrate significant preclinical activity against ALL, which has led to a number of clinical trials. Moreover, rapalogs can synergize with a number of conventional cytotoxic agents and overcome pathways of chemotherapeutic resistance for drugs commonly used in ALL treatment, including methotrexate and corticosteroids. Based on preclinical data, rapalogs are also being studied in AML, CML, and non-Hodgkin's lymphoma. Recently, significant progress has been made using rapalogs to treat pre-malignant lymphoproliferative disorders, including the autoimmune lymphoproliferative syndrome (ALPS); complete remissions in children with otherwise therapy-resistant disease have been seen. Rapalogs only block one component of the pathway (mTORC1), and newer agents are under preclinical and clinical development that can target different and often multiple protein kinases in the PI3K/AKT/mTOR pathway. Most of these agents have been tolerated in early-phase clinical trials. A number of PI3K inhibitors are under investigation. Of note, most of these also target other protein kinases. Newer agents are under development that target both mTORC1 and mTORC2, mTORC1 and PI3K, and the triad of PI3K, mTORC1, and mTORC2. Preclinical data suggest these dual- and multi-kinase inhibitors are more potent than rapalogs against many of the aforementioned hematologic malignancies. Two classes of AKT inhibitors are under development, the alkyl-lysophospholipids (APLs) and small molecule AKT inhibitors. Both classes have agents currently in clinical trials. A number of drugs are in development that target other components of the pathway, including eukaryotic translation initiation factor (eIF) 4E (eIF4E) and phosphoinositide-dependent protein kinase 1 (PDK1). Finally, a number of other key signaling pathways interact with PI3K/AKT/mTOR, including Notch, MNK, Syk, MAPK, and aurora kinase. These alternative pathways are being targeted alone and in combination with PI3K/AKT/mTOR inhibitors with promising preclinical results in pediatric hematologic malignancies. This review provides a comprehensive overview of the abnormalities in the PI3K/AKT/mTOR signaling pathway in pediatric hematologic malignancies, the agents that are used to target this pathway, and the results of preclinical and clinical trials, using those agents in childhood hematologic cancers.

Sarcomas other than Kaposi sarcoma occurring in immunodeficiency: interpretations from a systematic literature review

PURPOSE OF REVIEW

In immunodeficiency, an increased sarcoma risk is confirmed for Kaposi's sarcoma. Whether rates of other sarcoma subtypes are elevated in the setting of immunodeficiency is not known. We therefore reviewed published case reports on HIV and AIDS patients and organ transplant recipients with sarcomas. For comparison, we assessed sarcomas in the U.S. general population using Surveillance Epidemiology End Results (SEER) data.

RECENT FINDINGS

A total of 176 non-Kaposi sarcoma were identified, 75 in people with HIV and AIDS and 101 in transplant recipients. Leiomyosarcomas (n = 101) were the most frequently reported sarcomas, followed by angiosarcomas (n = 23) and fibrohistiocytic tumors (n = 17). Leiomyosarcomas were reported with two age peaks, in children and young adults. Epstein-Barr virus (EBV) was detected in the tumor cells in 85 and 88% of leiomyosarcomas in HIV-infected people and transplant recipients, respectively. Angiosarcomas and fibrohistiocytic tumors were most frequently reported in men. Among kidney transplant recipients, 20% of sarcomas arose at the site of an arteriovenous fistula. In comparison, leiomyoscarcomas, angiosarcomas, and fibrohistiocytic tumors comprised 16.9, 3.8, and 18.7% of sarcomas in the U.S. general population.

SUMMARY

Leiomyosarcoma and angiosarcoma may occur disproportionately in immunodeficiency. Leiomyosarcomas appear causatively linked to EBV, whereas angiosarcomas might be correlated with an arteriovenous fistula. Additional studies are necessary to understand the contribution of immunodeficiency to the cause of these sarcomas.

Hepatitis C virus recurrence and immunosuppression-free state after liver transplantation

HCV-related disease is the most common indication for liver transplantation (LT). HCV recurrence, which is almost universal, has a significant impact on patient and graft survival after LT and still represents a great unsolved issue for the liver transplant community. Several treatment strategies have been proposed. Since antiviral therapy has limited efficacy and can be administrated only in selected transplant recipients and additionally that immunosuppressive drugs have a negative impact on HCV re-infection, the achievement of an immunosuppression-free state after LT could play a central role in the avoidance of rapid HCV recurrence.

Castleman disease in a pediatric liver transplant recipient: a case report and literature review

Castleman disease is a rare hematologic disorder, closely linked to the HHV-8, and most commonly observed in immunocompromised individuals. Thirteen months following a liver transplant for CPS-1 defect, a 15-month-old boy presented with fevers, anemia, and growth retardation. Abdominal CT scan showed splenomegaly and generalized lymphadenopathy. Histology of chest wall lymph nodes revealed a mixed CD3+ T-cell and CD20+ B-cell population with atretic germinal centers consistent with multicentric Castleman disease. Qualitative DNA PCR detected HHV-8 in the resected lymph node and in the blood, supporting the diagnosis. Immunosuppression was tapered, and he was transitioned from tacrolimus to sirolimus. His graft function remained stable, and repeat imaging showed regression of the lymphadenopathy. The child is living one yr after Castleman disease diagnosis with a well-functioning graft. Castleman disease is a potential complication of solid organ transplant and HHV-8 infection. Reduction in immunosuppression and switch to sirolimus may be an effective strategy to treat this condition.

[Recent options in drug therapy after solid organ transplantation]

Solid organ transplantation has shown improvement in patient and graft survival rates due to the development of immunosuppression in the last fifty years; however only the last two decades led to the development of new, baseline immunosuppressive drugs that avoid the unlikely side effects of calcineurin inhibitors, especially nephrotoxicity. The transplanted organ is foreign to the host and, therefore, it induces a complex immune response of the recipient. In this review, a brief outline of immune response is given, followed by the introduction of new immunosuppressive drugs acting via variant pathways. These are compounds which are already in use or becoming shortly available and are potential future alternatives for the calcineurin inhibitors. This paper highlights the role of co-stimulation blockade with belatacept and the recently even more intensively studied field of tolerance induction.

Liver transplantation and hepatitis C

Hepatitis-C-virus- (HCV-) related end-stage cirrhosis is the primary indication for liver transplantation in many countries. Unfortunately, however, HCV is not eliminated by transplantation and graft reinfection is universal, resulting in fibrosis, cirrhosis, and finally graft decompensation. The use of poor quality organs, particularly from older donors, has a highly negative impact on the severity of recurrence and patient/graft survival. Although immunosuppressive regimens have a considerable impact on the outcome, the optimal regimen after liver transplantation for HCV-infected patients remains unclear. Disease progression monitoring with protocol biopsy and new noninvasive methods is essential for predicting patient/graft outcome and starting antiviral treatment with the appropriate timing. Antiviral treatment with pegylated interferon and ribavirin is currently considered the most promising regimen with a sustained viral response rate of around 30% to 35%, although the survival benefit of this regimen remains to be investigated. Living-donor liver transplantation is now widely accepted as an established treatment for HCV cirrhosis and the results are equivalent to those of deceased donor liver transplantation.

Tolerogenic therapies in transplantation

Since the concept of immunologic tolerance was discovered in the 1940s, the pursuit of tolerance induction in human transplantation has led to a rapid development of pharmacologic and biologic agents. Short-term graft survival remains an all-time high, but successful withdrawal of immunosuppression to achieve operational tolerance rarely occurs outside of liver transplantation. Collaborative efforts through the NIH sponsored Immune Tolerance Network and the European Commission sponsored Reprogramming the Immune System for Establishment of Tolerance consortia have afforded researchers opportunity to evaluate the safety and efficacy of tolerogenic strategies, investigate mechanisms of tolerance, and identify molecular and genetic markers that distinguish the tolerance phenotype. In this article, we review traditional and novel approaches to inducing tolerance for organ transplantation, with an emphasis on their translation into clinical trials.

Mycophenolic acid augments interferon-stimulated gene expression and inhibits hepatitis C Virus infection in vitro and in vivo

Mycophenolic acid (MPA) is a highly effective immunosuppressant that has broad antiviral activity against different viruses and can act in synergy with interferon-α (IFN-α) on hepatitis C virus (HCV) replication. MPA is a potent inosine monophosphate dehydrogenase (IMPDH) inhibitor but the antiviral mechanisms are less understood. The aim of this study was to investigate the inhibition of HCV infection by MPA and the molecular basis for its synergy with IFN-α. The role of IMPDH and interferon-stimulated genes (ISGs) was investigated in two HCV models using gain- or loss-of-function approaches. The in vivo effect of MPA treatment was studied in NOD/SCID mice engrafted with HCV replicon cells. Potent antiviral effects of MPA at clinically relevant concentrations were observed with both the subgenomic and JFH1-derived infectious HCV models. MPA treatment in mice resulted in a specific and robust inhibition of HCV replication. Ectopic expression of an MPA-resistant IMPDH2 mutant in HCV host cells completely reversed the antiproliferative effect of MPA but only partially affected the antiviral potency. However, similar to ribavirin, MPA induced expression of multiple antiviral ISGs, including interferon regulatory factor 1 (IRF1). Cotreatment of MPA with IFN-α resulted in additive effects on ISG expression and enhanced IFN-induced luciferase reporter activity. Knockdown of IRF1, but not IFITM3, significantly attenuated the inhibition of HCV replication by MPA.

CONCLUSION

MPA exerts a potent anti-HCV effect in vitro and in mice and acts in synergy with IFN-α. MPA's antiviral activity partially depends on IMPDH but also involves stimulation of ISGs, providing a molecular basis for its synergy with IFN-α.

Viral infection in renal transplant recipients

Viruses are among the most common causes of opportunistic infection after transplantation. The risk for viral infection is a function of the specific virus encountered, the intensity of immune suppression used to prevent graft rejection, and other host factors governing susceptibility. Although cytomegalovirus is the most common opportunistic pathogen seen in transplant recipients, numerous other viruses have also affected outcomes. In some cases, preventive measures such as pretransplant screening, prophylactic antiviral therapy, or posttransplant viral monitoring may limit the impact of these infections. Recent advances in laboratory monitoring and antiviral therapy have improved outcomes. Studies of viral latency, reactivation, and the cellular effects of viral infection will provide clues for future strategies in prevention and treatment of viral infections. This paper will summarize the major viral infections seen following transplant and discuss strategies for prevention and management of these potential pathogens.

Virus-drug interactions--molecular insight into immunosuppression and HCV

Liver transplantation is an effective treatment for end-stage liver disease that is attributable to chronic HCV infection. However, long-term outcomes are compromised by universal virological recurrence in the graft. Reinfection that occurs after transplantation has increased resistance to current interferon-based antiviral therapy and often leads to accelerated development of cirrhosis. Important risk factors for severe HCV recurrence are linked to immunosuppression. Owing to the lack of good randomized, controlled trials, the optimal choice of immunosuppressants is still debated. By contrast, much progress has been made in the understanding of HCV biology and the antiviral action of interferons. These new insights have greatly expanded our knowledge of the molecular interplay between HCV and immunosuppressive drugs. In this article, we explore the effect of different immunosuppressants on the complex cellular events involved in HCV infection and interferon signalling. Potential implications for clinical practice and future drug development are discussed.

Immunosuppression and HCV recurrence after liver transplantation

HCV related liver disease is the most common indication for liver transplantation. Recurrence of HCV infection is universal and has a substantial impact on patient and graft survival. Immunosuppression is a major factor responsible for the accelerated recurrence and compressed natural history of recurrent HCV infection. Accumulating experience has provided data to support certain strategies for immunosuppressive regimens. From the available evidence, more severe recurrence results from repeated bolus corticosteroid therapy and anti-lymphocyte antibodies used to treat rejection. Low dose and slow tapering of steroids are better than high dose maintenance and/or rapid tapering. Recent meta-analyses favour steroid-free regimens but these are complicated to interpret as the absence of steroids may simply represent less immunopotency. There is no difference in HCV recurrence between tacrolimus and cyclosporine regimens, but tacrolimus increases graft and patient survival in HCV transplanted patients. There may be a beneficial effect of maintenance azathioprine given for 6 months or longer. There is no conclusive evidence for benefit of mycophenolate and interleukin-2 receptor blockers. Few data are available for mTOR inhibitors. Better evidence is needed to establish the optimal immunosuppressive regimen for HCV recipients and more randomized trials should be performed.

Association of immunosuppressive maintenance regimens with posttransplant lymphoproliferative disorder in kidney transplant recipients

BACKGROUND

The association of immunosuppressive regimens (ISRs) with posttransplant lymphoproliferative disorder (PTLD) may be related with the Epstein-Barr virus (EBV) recipient serostatus.

METHODS

We selected primary kidney transplant recipients from Organ Procurement Transplant Network/United Network for Organ Sharing database (2000-2009) who were discharged with a functioning graft and were receiving an ISR including an antiproliferative drug and a calcineurin inhibitor as follows: mycophenolate mofetil (MMF)/mycophenolate sodium+tacrolimus (TAC), MMF+cyclosporine A (CsA); mammalian target of rapamycin inhibitor (mTORi)+TAC; and mTORi+CsA. Adjusted risks of PTLD, rejection, death, and graft failure were examined in all recipients and compared between EBV+ and EBV- recipients.

RESULTS

Of 114,025 recipients, 754 developed PTLD (5-year incidence of 0.84%). Adjusted hazard ratio for PTLD was 4.39 (95% CI: 3.60-5.37) for EBV- versus EBV+ recipients; and 1.40 (95% CI: 1.03-1.90) for mTORi+TAC, 0.80 (95% CI: 0.65-0.99) for MMF+CsA, and 0.90 (95% CI: 0.57-1.42) for mTORi+CsA, versus MMF+TAC users. In EBV- recipients, hazard ratio for PTLD was 1.98 (95% CI: 1.28-3.07) for mTORi+TAC, 0.45 (95% CI: 0.28-0.72) for MMF+CsA, and 0.84 (95% CI: 0.39-1.80) for mTORi+CsA users versus MMF+TAC. No difference was seen in EBV+ recipient groups. Rejection rates were higher among MMF+CsA recipients in both EBV groups. Death and graft failure risk were increased in all EBV+ISR groups, while in EBV- these risks were only increased in mTORi+TAC group versus MMF+TAC.

CONCLUSIONS

In EBV- recipients, immunosuppression with mTORi+TAC was associated with increased risk of PTLD, death, and graft failure, while MMF+CsA use was associated with a trend to increased risk of rejection, lower PTLD risk, and similar risk for graft failure when compared with MMF+TAC.

Hot-topic debate on kidney function: renal-sparing approaches are beneficial

1. Renal function is frequently compromised in candidates for transplantation with advanced cirrhosis. These patients frequently have chronic and irreversible kidney changes at the time of transplantation. 2. The accumulated incidence of chronic renal failure is high in liver transplant recipients. Chronic renal failure has a deleterious impact on the outcome. 3. Calcineurin inhibitor (CNI)-based immunosuppression is highly effective at preventing rejection. However, CNI nephrotoxicity has a central role in the occurrence of chronic renal failure. 4. Renal function impairment frequently occurs within the first year after transplantation. Once renal function is significantly impaired [glomerular filtration rate (GFR) < 60 mL/minute/1.73 m(2) ], any intervention is unlikely to result in a return to normal renal function. Early interventions are needed to prevent chronic and irreversible kidney injury. 5. De novo CNI minimization has been proven to be effective at reducing the rate of impaired renal function after transplantation. The reduction in the CNI doses should be offset by the addition of mycophenolate mofetil or enteric-coated mycophenolate sodium. 6. Delayed CNI minimization in patients with established renal insufficiency may result in a significant improvement in the GFR, even though the increase in the GFR after minimization is generally modest. 7. Mammalian target of rapamycin (mTOR) inhibitors are considered nonnephrotoxic immunosuppressive agents. They may be an option for improving renal function in liver transplant recipients. However, not all patients with renal dysfunction benefit from a switch to mTOR inhibitors. In addition, the benefits in terms of renal function should be balanced against specific side effects. 8. New immunosuppressive agents without intrinsic nephrotoxicity are currently under development for solid organ transplantation. These agents could help to reduce the burden of impaired renal function in transplantation in the near future.

Evolving concepts in the selection of immunosuppression regimen for liver transplant recipients

The introduction of calcineurin inhibitor (CNI) based immunosuppression has revolutionized the field of liver transplantation by dramatically reducing the incidence of acute cellular rejection and prolonging patient and allograft survival. However, the introduction of CNIs has also come at the price of increased patient morbidity, particularly with regard to the well-known nephrotoxic effects of the medications. In an effort to minimize the adverse effects, immunosuppression regimen have evolved to include the use of various induction agents and purine synthesis inhibitors to limit the dose of CNI necessary to achieve low acute cellular rejection rates. Careful assessments of risks and benefits are needed as these newer agents have their own side effect profiles. In addition, the impact of newer immunosuppression regimen on hepatitis C (HCV) recurrence has not been completely elucidated. This review will provide an overview of the most common immunosuppression regimen used in liver transplantation and discuss their impact on acute cellular rejection, patient and allograft survival, and HCV recurrence.