Mechanisms of myeloid-derived suppressor cell-mediated immunosuppression in colorectal cancer and related therapies

Severe immunosuppression is a hallmark of colorectal cancer(CRC).Myeloid-derived suppressor cells(MDSCs),one of the most abundant components of the tumor stroma,play an important role in the invasion,metastasis,and immune escape of CRC.MDSCs create an immunosuppressive microenvironment by inhibiting the proliferation and activation of immunoreactive cells,including T and natural killer cells,as well as by inducing the proliferation of immunosuppressive cells,such as regulatory T cells and tumor-associated macrophages,which,in turn,promote the growth of cancer cells.Thus,MDSCs are key contributors to the emergence of an immunosup-pressive microenvironment in CRC and play an important role in the breakdown of antitumor immunity.In this narrative review,we explore the mechanisms through which MDSCs contribute to the immunosuppressive microenvironment,the current therapeutic approaches and technologies targeting MDSCs,and the therapeutic potential of modulating MDSCs in CRC treatment.This study provides ideas and methods to enhance survival rates in patients with CRC.

Impact of STAT-signaling pathway on cancer-associated fibroblasts in colorectal cancer and its role in immunosuppression

Colorectal cancer(CRC)remains one of the most commonly diagnosed and deadliest types of cancer worldwide.CRC displays a desmoplastic reaction(DR)that has been inversely associated with poor prognosis;less DR is associated with a better prognosis.This reaction generates excessive connective tissue,in which cancer-associated fibroblasts(CAFs)are critical cells that form a part of the tumor microenvironment.CAFs are directly involved in tumorigenesis through different mechanisms.However,their role in immunosuppression in CRC is not well understood,and the precise role of signal transducers and activators of transcription(STATs)in mediating CAF activity in CRC remains unclear.Among the myriad chemical and biological factors that affect CAFs,different cytokines mediate their function by activating STAT signaling pathways.Thus,the harmful effects of CAFs in favoring tumor growth and invasion may be modulated using STAT inhibitors.Here,we analyze the impact of different STATs on CAF activity and their immunoregulatory role.

Sepsis-induced immunosuppression:mechanisms,diagnosis and current treatment options

Sepsis is a common complication of combat injuries and trauma,and is defined as a life-threatening organ dysfunction caused by a dysregulated host response to infection.It is also one of the significant causes of death and increased health care costs in modern intensive care units.The use of antibiotics,fluid resuscitation,and organ support therapy have limited prognostic impact in patients with sepsis.Although its pathophysiology remains elusive,immunosuppression is now recognized as one of the major causes of septic death.Sepsis-induced immunosuppression is resulted from disruption of immune homeostasis.It is characterized by the release of antiinflammatory cytokines,abnormal death of immune effector cells,hyperproliferation of immune suppressor cells,and expression of immune checkpoints.By targeting immunosuppression,especially with immune checkpoint inhibitors,preclinical studies have demonstrated the reversal of immunocyte dysfunctions and established host resistance.Here,we comprehensively discuss recent findings on the mechanisms,regulation and biomarkers of sepsis-induced immunosuppression and highlight their implications for developing effective strategies to treat patients with septic shock.

Expert consensus on the monitoring and treatment of sepsis-induced immunosuppression

Emerged evidence has indicated that immunosuppression is involved in the occurrence and development of sepsis.To provide clinical practice recommendations on the immune function in sepsis,an expert consensus focusing on the monitoring and treatment of sepsis-induced immunosuppression was developed.Literature related to the immune monitoring and treatment of sepsis were retrieved from PubMed,Web of Science,and Chinese National Knowledge Infrastructure to design items and expert opinions were collected through an online questionnaire.Then,the Delphi method was used to form consensus opinions,and RAND appropriateness method was developed to provide consistency evaluation and recommendation levels for consensus opinions.This consensus achieved satisfactory results through two rounds of questionnaire survey,with 2 statements rated as perfect consistency,13 as very good consistency,and 9 as good consistency.After summarizing the results,a total of 14 strong recommended opinions,8 weak recommended opinions and 2 non-recommended opinions were produced.Finally,a face-to-face discussion of the consensus opinions was performed through an online meeting,and all judges unanimously agreed on the content of this consensus.In summary,this expert consensus provides a preliminary guidance for the monitoring and treatment of immunosuppression in patients with sepsis.

Dupilumab for Treatment of Food-Dependent, Exercise-Induced Anaphylaxis: Report of One Case

Food-dependent,exercise-induced anaphylaxis(FDEIA)is a potentially life-threatening disorder that often occurs with exercise,and patients typically have eaten a specific food within hours before disease onset.This disease is exceedingly rare,with a prevalence of 0.02%.No well-recognized prevention or treatment strategy has been available for FDEIA except avoiding triggers strictly.Here we report an 11-year-old boy with a history of recurrent anaphylaxis of unknown etiology more than 10 times within two years.As the anaphylactic symptoms had not been controlled after traditional treatments,the patient was given subcutaneous injection of dupilumab seven times within 33 weeks.During dupilumab treatments,the patient was exposed to culprit mushrooms plus exercises at least twice a month but without notable anaphylaxis.Thus,dupilumab may improve the allergic reactions in FDEIA patients.

Variations in Inflammatory Cells and IL-6 in Long-Distance Runners Susceptible to Exercise-Induced Bronchospasm and Previously Treated with Salbutamol

Background: Exercise-Induced Bronchospasm (EIB) is an inflammatory condition characterized by severe airway constriction following the mobilization of inflammatory cells and interleukin-6 (IL-6). When severe, EIB can require the use of pressurized salbutamol to treat athletes. This study investigated the nature of the systemic changes in inflammatory cells and post-exercise IL-6 concentrations after salbutamol treatment in EIB-susceptible distance runners. Materials and Methods: This was an experimental study that enrolled 12 long-distance runners. In Session A, the participants completed a treadmill exercise test, and those who had a maximum expiratory volume per second (FEV1) that was decreased by at least 10% compared to their base value were placed in the EIB-susceptible group (EIB+) (n = 6). Those whose FEV1 did not meet this criterion were placed in the nonresponsive (EIB?) group (n = 6). Before the Session B exercise, athletes in the BIE+ group inhaled two puffs of salbutamol (EIB+ Salb), while their EIB? counterparts received no treatment. Spirometry was performed before and after the exercise using a Spirobank G portable spirometer. Blood samples were taken before, immediately after and 2 hours after the stress test. Results: The mean post-exercise FEV1 values were not significantly different (p > 0.05) between the EIB+ Salb group and the EIB? group. The systemic changes in inflammatory cells and IL-6 concentrations in the EIB+ runners after salbutamol treatment were similar to those observed in their EIB? counterparts. Conclusion: Salbutamol pretreatment improved the systemic immune status of EIB-susceptible athletes.

Molecular chaperones in stroke-induced immunosuppression

Stroke-induced immunosuppression is a process that leads to peripheral suppression of the immune system after a stroke and belongs to the central nervous system injury-induced immunosuppressive syndrome.Stroke-induced immunosuppression leads to increased susceptibility to post-stroke infections,such as urinary tract infections and stroke-associated pneumonia,worsening prognosis.Molecular chaperones are a large class of proteins that are able to maintain proteostasis by directing the folding of nascent polypeptide chains,refolding misfolded proteins,and targeting misfolded proteins for degradation.Various molecular chaperones have been shown to play roles in stroke-induced immunosuppression by modulating the activity of other molecular chaperones,cochaperones,and their associated pathways.This review summarizes the role of molecular chaperones in stroke-induced immunosuppression and discusses new approaches to restore host immune defense after stroke.

Study on Mechanism of Dendrobium officinale Kimura et Migo in Preventing and Treating Exercise-induced Muscle Damage(EIMD)in Rats

[Objectives]This study was conducted to observe the mechanism of Dendrobium officinale Kimura et Migo on gastrocnemius muscle in rats with exercise-induced muscle damage(EIMD).[Methods]The micro-injury model of skeletal muscle was established by treadmill training.Forty two SD rats were randomly divided into a control group,1,12 and 24 h exercise groups,D.officinale 2 ml+1 h exercise group,D.officinale 2 ml+12 h exercise group,and D.officinale 2 ml+24 h exercise group,with 6 rats in each group.Various D.officinale groups were given the drug once in the morning and once in the evening at a dose of 2 ml/time,a week in advance.Except for the quiet group,the samples were collected from the 1,12 and 24 h exercise groups after anesthesia following 1,12 and 24 h of exercise for the last time,respectively,and the D.officinale 2 ml+1 h exercise group,D.officinale 2 ml+12 h exercise group and D.officinale 2 ml+24 h exercise group were also sampled after anesthesia following 1,12 and 24 h of exercise for the last time,respectively.The contents of ATP,CK-MM and CK in rat serum were determined by enzyme-linked immunosorbent assay(ELISA).The histopathological changes of gastrocnemius muscle were observed by HE staining.PCR and Western-blot detection were carried out to analyze the effects of D.officinale on IGF-1 mRNA and protein expression in gastrocnemius muscle.[Results]Compared with the quiet group,the ATP contents in the serum of rats in the 1,12 and 24 h exercise groups significantly decreased(P<0.01),while the CK and CK-MM contents significantly increased(P<0.01).The expression of IGF-1 mRNA and protein in the gastrocnemius muscle tissue significantly increased(P<0.01).Compared with the 1 h exercise group,the ATP content and IGF-1 protein expression in the gastrocnemius muscle tissue of the D.officinale liquid+1 h exercise group significantly increased(P<0.05),while the CK and CK-MM contents significantly decreased(P<0.01).Compared with the 12 h exercise group,the D.officinale liquid+12 h exercise group showed a significant increase in ATP content(P<0.01),significant increases in IGF-1 mRNA and protein expression in the gastrocnemius muscle tissue(P<0.01),and significant decreases in CK and CK-MM contents(P<0.01).Compared with the 24 h exercise group,the ATP content and IGF-1 mRNA and protein expression in the gastrocnemius muscle tissue of the D.officinale liquid+24 h exercise group significantly increased(P<0.01),while the CK and CK-MM contents significantly decreased(P<0.01).From the pathological tissue morphology of the gastrocnemius muscle in rats with EIMD treated with D.officinale,it could be concluded that the gastrocnemius muscle of each exercise group was significantly damaged,and the damage was significantly alleviated after administration of D.officinale liquid.[Conclusions]The effects and mechanism of D.officinale on prevention and treatment of EIMD in rats might be related to the promotion of IGF-1 mRNA and protein expression in injured tissues by reducing ATP energy consumption,CK-MM and CK activity.

Effects of Rosa roxburghii&edible fungus fermentation broth on immune response and gut microbiota in immunosuppressed mice

With the rise of probiotics fermentation in food industry,fermented foods have attracted worldwide attention.In this study,protective effects of Rosa roxburghii&edible fungus fermentation broth(REFB)on immune function and gut health in Cyclophosphamide induced immunosuppressed mice were investigated.Results showed that REFB could improve the immune organ index,and promote the proliferation and differentiation of splenic T lymphocytes.In addition,it attenuated intestinal mucosal damage and improved intestinal cellular immunity.REFB administration also up-regulated the expression of IL-4,INF-γ,TNF-α,T-bet and GATA-3 mRNA in small intestine.Furthermore,administration of REFB modulated gut microbiota composition and increased the relative abundance of beneficial genus,such as Bacteroides.It also increased the production of fecal short-chain fatty acids.These indicate that REFB has the potential to improve immunity,alleviate intestinal injury and regulate gut microbiota in immunosuppressed mice.

Mechanisms of tumor immunosuppressive microenvironment formation in esophageal cancer

As a highly invasive malignancy,esophageal cancer(EC)is a global health issue,and was the eighth most prevalent cancer and the sixth leading cause of cancerrelated death worldwide in 2020.Due to its highly immunogenic nature,emerging immunotherapy approaches,such as immune checkpoint blockade,have demonstrated promising efficacy in treating EC;however,certain limitations and challenges still exist.In addition,tumors may exhibit primary or acquired resistance to immunotherapy in the tumor immune microenvironment(TIME);thus,understanding the TIME is urgent and crucial,especially given the importance of an immunosuppressive microenvironment in tumor progression.The aim of this review was to better elucidate the mechanisms of the suppressive TIME,including cell infiltration,immune cell subsets,cytokines and signaling pathways in the tumor microenvironment of EC patients,as well as the downregulated expression of major histocompatibility complex molecules in tumor cells,to obtain a better understanding of the differences in EC patient responses to immunotherapeutic strategies and accurately predict the efficacy of immunotherapies.Therefore,personalized treatments could be developed to maximize the advantages of immunotherapy.

Update on the reciprocal interference between immunosuppressive therapy and gut microbiota after kidney transplantation

Gut microbiota is often modified after kidney transplantation.This principally happens in the first period after transplantation.Antibiotics and,most of all,immunosuppressive drugs are the main responsible.The relationship between immunosuppressive drugs and the gut microbiota is bilateral.From one side immunosuppressive drugs modify the gut microbiota,often generating dysbiosis;from the other side microbiota may interfere with the immunosuppressant pharmacokinetics,producing products more or less active with respect to the original drug.These phenomena have influence over the graft outcomes and clinical consequences as rejections,infections,diarrhea may be caused by the dysbiotic condition.Corticosteroids,calcineurin inhibitors such as tacrolimus and cyclosporine,mycophenolate mofetil and mTOR inhibitors are the immunosuppressive drugs whose effect on the gut microbiota is better known.In contrast is well known how the gut microbiota may interfere with glucocorticoids,which may be transformed into androgens.Tacrolimus may be transformed by microbiota into a product called M1 that is 15-fold less active with respect to tacrolimus.The pro-drug mycophenolate mofetil is normally transformed in mycophenolic acid that according the presence or not of microbes producing the enzyme glucuronidase,may be transformed into the inactive product.

Inflammation and immunosuppression in severe acute pancreatitis

Acute pancreatitis(AP) is a common disease,which usually exists in its mild form.However,in a fifth of cases,the disease is severe,with local pancreatic complications or systemic organ dysfunction or both.Because the development of organ failure is the major cause of death in AP,early identification of patients likely to develop organ failure is important.AP is initiated by intracellular activation of pancreatic proenzymes and autodigestion of the pancreas.Destruction of the pancreatic parenchyma first induces an inflammatory reaction locally,but may lead to overwhelming systemic production of inflammatory mediators and early organ failure.Concomitantly,anti-inflammatory cytokines and specific cytokine inhibitors are produced.This anti-inflammatory reaction may overcompensate and inhibit the immune response,rendering the host at risk of systemic infection.At present,there is no specific treatment for AP.Increased understanding of the pathogenesis of systemic inflammation and development of organ dysfunction may provide us with drugs to ameliorate physiological disturbances.

Inflammatory bowel disease and cancer: The role of inflammation, immunosuppression, and cancer treatment

In patients with inflammatory bowel disease(IBD), chronic inflammation is a major risk factor for the development of gastrointestinal malignancies. The pathogenesis of colitis-associated cancer is distinct from sporadic colorectal carcinoma and the critical molecular mechanisms underlying this process have yet to be elucidated. Patients with IBD have also been shown to be at increased risk of developing extra-intestinal malignancies. Medical therapies that diminish the mucosal inflammatory response represent the foundation of treatment in IBD, and recent evidence supports their introduction earlier in the disease course. However, therapies that alter the immune system, often used for long durations, may also promote carcinogenesis. As the population of patients with IBD grows older, with longer duration of chronic inflammation and longer exposure to immunosuppression, there is an increasing risk of cancer development. Many of these patients will require cancer treatment, including chemotherapy, radiation, hormonal therapy, and surgery. Many patients will require further treatment for their IBD. This review seeks to explore the characteristics and risks of cancer in patients with IBD, and to evaluate the limited data on patients with IBD and cancer, including management of IBD after a diagnosis of cancer, the effects of cancer treatment on IBD, and the effect of IBD and medications for IBD on cancer outcomes.

Role of IL-10 and TGF-β1 in local immunosuppression in HPV-associated cervical neoplasia

Cervical cancer is a worldwide disease that constitutes a significant public health problem, especially in developing countries, not only due to its high incidence but also because the most affected population comprises women who belong to marginalized socio-economic classes. Clinical and molecular research has identified immunological impairment in squamous intraepithelial cervical lesions and cervical cancer patients. Human Papillomavirus(HPV) has several mechanisms for avoiding the immune system: it down-regulates the expression of interferon and upregulates interleukin(IL)-10and transforming growth factor(TGF)-β1 to produce a local immunosuppressive environment, which, along with altered tumor surface antigens, forms an immunosuppressive network that inhibits the antitumor immune response. In this review we analyzed the available data on several deregulated cellular immune functions in patients with NIC Ⅰ, NIC Ⅱ and NIC Ⅲ and cervical cancer. The effects of immunosuppressive cytokines on innate immune response, T-cell activation and cellular factors that promote tumor cell proliferation in cervical cancer patients are summarized. We discuss the functional consequences of HPV E2, E6, and E7 protein interactions with IL-10 and TGF-β1 promoters in the induction of these cytokines and postulate its effect on the cellular immune response in squamous intraepithelial cervical lesions and cervical cancer patients. This review provides a comprehensive picture of the immunological functions of IL-10 and TGF-β1 in response to HPV in humans.

De novo malignancies after liver transplantation: The effect of immunosuppression-personal data and review of literature

BACKGROUND Immunosuppression has undoubtedly raised the overall positive outcomes in the post-operative management of solid organ transplantation. However, long-term exposure to immunosuppression is associated with critical systemic morbidities. De novo malignancies following orthotopic liver transplants (OLTs) are a serious threat in pediatric and adult transplant individuals. Data from different experiences were reported and compared to assess the connection between immunosuppression and de novo malignancies in liver transplant patients. AIM To study the role of immunosuppression on the incidence of de novo malignancies in liver transplant recipients. METHODS A systematic literature examination about de novo malignancies and immunosuppression weaning in adult and pediatric OLT recipients was described in the present review. Worldwide data were collected from highly qualified institutions performing OLTs. Patient follow-up, immunosuppression discontinuation and incidence of de novo malignancies were reported. Likewise, the review assesses the differences in adult and pediatric recipients by describing the adopted immunosuppression regimens and the different type of diagnosed solid and blood malignancy.RESULTS Emerging evidence suggests that the liver is an immunologically privileged organ able to support immunosuppression discontinuation in carefully selected recipients. Malignancies are often detected in liver transplant patients undergoing daily immunosuppression regimens. Post-transplant lymphoproliferative diseases and skin tumors are the most detected de novo malignancies in the pediatric and adult OLT population, respectively. To date, immunosuppression withdrawal has been achieved in up to 40% and 60% of well-selected adult and pediatric recipients, respectively. In both populations, a clear benefit of immunosuppression weaning protocols on de novo malignancies is difficult to ascertain because data have not been specified in most of the clinical experiences. CONCLUSION The selected populations of tolerant pediatric and adult liver transplant recipients greatly benefit from immunosuppression weaning. There is still no strong clinical evidence on the usefulness of immunosuppression withdrawal in OLT recipients on malignancies. An interesting focus is represented by the complete reconstitution of the immunological pathways that could help in decreasing the incidence of de novo malignancies and may also help in treating liver transplant patients suffering from cancer.

Review on immunosuppression in liver transplantation

The optimal level of immunosuppression in solid organ transplantation,in particular for the liver,is a delicate balance between the benefit of preventing rejection and the adverse side effects of immunosuppression. There is uncertainty about when this level is achieved in any individual recipient. Immunosuppression regimens vary between individual centers and changes with time asnew agents and data are available. Presently concerns about the adverse side effects of calcineurin inhibitor,the main class of immunosuppressive agents used in liver transplantation(LT),has led to consideration of the use of antibody induction therapies for patients at higher risk of developing adverse side effects. The longevity of the transplanted organ is potentially improved by better management of rejection episodes and special consideration for tailoring of immunosuppression to the individual with viral hepatitis C,hepatocellular carcinoma or pregnancy. This review provides an overview of the current strategies for post LT immunosuppression and discusses modifications to consider for special patient populations.

Hepatitis B virus reactivation in hepatitis B virus surface antigen negative patients receiving immunosuppression: A hidden threat

AIM: To present the characteristics and the course of a series of anti- hepatitis B virus core antibody (HBc) antibody positive patients, who experienced hepatitis B virus (HBV) reactivation after immunosuppression. METHODS: We retrospectively evaluated in our tertiary centers the medical records of hepatitis B virus surface antigen (HBsAg) negative patients who suffered from HBV reactivation after chemotherapy or immunosuppression during a 3-year period (2009-2011). Accordingly, the clinical, laboratory and virological characteristics of 10 anti-HBc (+) anti-HBs (-)/HBsAg (-) and 4 anti-HBc (+)/antiHBs (+)/HBsAg (-) patients, who developed HBV reactivation after the initiation of chemotherapy or immunosuppressive treatment were analyzed. Quantitative determination of HBV DNA during reactivation was performed in all cases by a quantitative real time polymerase chain reaction kit (COBAS Taqman HBV Test; cut-off of detection: 6 IU/mL). RESULTS: Twelve out of 14 patients were males; median age 74.5 years. In 71.4% of them the primary diagnosis was hematologic malignancy; 78.6% had received rituximab (R) as part of the immunosuppressive regimen. The median time from last chemotherapy schedule till HBV reactivation for 10 out of 11 patients who received R was 3 (range 2-17) mo. Three patients (21.4%) deteriorated, manifesting ascites and hepatic encephalopathy and 2 (14.3%) of them died due to liver failure. CONCLUSION: HBsAg-negative anti-HBc antibody positive patients can develop HBV reactivation even 2 years after stopping immunosuppression, whereas prompt antiviral treatment on diagnosis of reactivation can be lifesaving.

Individualized immunosuppression: new strategies from pharmacokinetics,pharmacodynamics and pharmacogenomics

The ultimate goal of transplantation is the donor-specific immune tolerance, but at least in the first 15 to 20 years of this century, immunosuppressive agents are still the determinant of clinical outcome of transplant recipients. Individualizing patient's immunosuppression to optimize the balance between therapeutic efficacy and the occurrence of adverse events poses a great challenge to physicians. DATA SOURCES:The data in this article were taken mostly from MEDLINE (2000-2004), part of which were from the research of the authors. RESULTS:Individualized immunosuppression remains a problem because of the narrow therapeutic index and wide inter- and intra-patient variation of commonly-used im- munosuppressants. Recent progress in study of pharmaco-kinetics and pharmacodynamics improved the clinical outcome of transplant recipients. More importantly, the emergence of pharmacogenomics might provide a promising and complementary tool for traditional therapeutic drug monitoring (TDM). CONCLUSIONS:Individualizing organ recipient's immunosuppression to balance the therapeutic efficacy and the adverse events represents a great challenge to transplant clinicians. Pharmacogenomics shows great promise for an interesting and hopefully better future.

Catastrophic gastrointestinal complication of systemic immunosuppression

We present a case of acute upper gastrointestinal haemorrhage in a patient with systemic vasculitis immunosuppressed on cyclophosphamide and prednisolone.The patient presented with a diffuse haemorrhagic oesophagitis and a non-specific duodenitis.Biopsies taken from the oesophagus and duodenum demonstrated infection with herpes simplex virus(HSV)and cytomegalovirus(CMV)respectively.Viral infection of the upper gastrointestinal tract is a recognised complication of immunosuppression and HSV is one of the most common pathogens.CMV on the other hand most commonly causes a colitis or less commonly oesophagitis.CMV enteritis is rare as is the synchronous infection with two viral agents in an immunocompromised patient having being described in a few case series only.Viral infection of the gastrointestinal tract in immunocompromised patients should be treated with systemic anti-viral medication and consideration to withdrawal of the immunosuppressive therapy if possible and appropriate.The authors highlight the need for a high suspicion of viral infection in immunosuppressed patients presenting with upper gastrointestinal bleeding.

Efficacy of immunosuppression monotherapy after liver transplantation:A meta-analysis

AIM:To assess the advantages and disadvantages of immunosuppression monotherapy after transplantation and the impact of monotherapy on hepatitis C virus(HCV)recurrence.METHODS:Articles from Cochrane Hepato-Biliary Group Controlled Trials Register,the Cochrane Central Register of Controlled Trials in The Cochrane Library,MEDLINE,EMBASE,and Science Citation Index Expanded,including non-English literature identified in these databases,were searched up to January 2013.We included randomized clinical trials comparing various immunosuppression monotherapy and prednisone-based immunosuppression combinations for liver transplantation.The modified Jadad scale score or the Oxford quality scoring system was used.Meta-analyses were performed with weighted random-effects models.RESULTS:A total of 14 randomized articles including 1814 patients were identified.Eight trials including1214 patients compared tacrolimus monotherapy(n=610)vs tacrolimus plus steroids or triple therapy regarding acute rejection and adverse events(n=604).Five trials,including 285 patients,compared tacrolimus monotherapy(n=143)vs tacrolimus plus steroids or triple therapy regarding hepatitis C recurrence(n=142).Four trials including 273 patients compared cyclosporine monotherapy(n=148)vs cyclosporine and steroids regarding acute rejection and adverse events(n=125).Two trials including 170 patients compared mycophenolate mofetil monotherapy(n=86)vs combinations regarding acute rejection(n=84).There were no significant differences in the acute rejection rates between tacrolimus monotherapy(RR=1.04,P=0.620),and cyclosporine monotherapy(RR=0.89,P=0.770).Mycophenolate mofetil monotherapy had a significant increase in the acute rejection rate(RR=4.50,P=0.027).Tacrolimus monotherapy had no significant effects on the recurrence of hepatitis C(RR=1.03,P=0.752).More cytomegalovirus infection(RR=0.48,P=0.000)and drug-related diabetes mellitus(RR=0.54,P=0.000)were observed in the immunosuppression combination therapy groups.CONCLUSION:Tacrolimus and cyclosporine monotherapy may be as effective as immunosuppression combination therapy.Mycophenolate mofetil monotherapy was not considerable.Tacrolimus monotherapy does not increase recurrence of HCV.