Mycophenolate mofetil-based immunosuppression and cytokine genotypes: effects on monokine secretion and antigen presentation in long-term renal transplant recipients

Skin cancer prevention - Recent advances and unmet challenges

Cutaneous squamous cell carcinoma (cSCC) is the second most common malignancy in the world. Among many identified risk factors, immunosuppression is a major factor that contributes to cSCC development. Organ transplant recipients (OTRs) are at markedly increased risk of developing multiple cSCCs with a propensity for advanced metastatic disease, leading to significant morbidity and mortality. The severity of the cSCC phenotype in OTRs highlights the urgent need to identify effective preventive modalities in this population. Despite recent advances in skin cancer prevention (e.g., nicotinamide) and treatment (e.g., immune checkpoint blockade), these modalities have limited utility in OTRs due to the lack of efficacy or significant side effect. Topical treatments against precancerous skin lesions, actinic keratosis (AK), remain the primary strategy to prevent cSCC in OTRs, which also have significant deficiencies in this population. Herein, we review the epidemiology, risk factors, and current cSCC prevention strategies. We highlight the gaps and future clinical strategies to address cSCC risk in high-risk populations.

Multiple Shades of Gray-Macrophages in Acute Allograft Rejection

Long-term results following solid organ transplantation do not mirror the excellent short-term results achieved in recent decades. It is therefore clear that current immunosuppressive maintenance protocols primarily addressing the adaptive immune system no longer meet the required clinical need. Identification of novel targets addressing this shortcoming is urgently needed. There is a growing interest in better understanding the role of the innate immune system in this context. In this review, we focus on macrophages, which are known to prominently infiltrate allografts and, during allograft rejection, to be involved in the surge of the adaptive immune response by expression of pro-inflammatory cytokines and direct cytotoxicity. However, this active participation is janus-faced and unspecific targeting of macrophages may not consider the different subtypes involved. Under this premise, we give an overview on macrophages, including their origins, plasticity, and important markers. We then briefly describe their role in acute allograft rejection, which ranges from sustaining injury to promoting tolerance, as well as the impact of maintenance immunosuppressants on macrophages. Finally, we discuss the observed immunosuppressive role of the vitamin-like compound tetrahydrobiopterin and the recent findings that suggest the innate immune system, particularly macrophages, as its target.

Role of donor macrophages after heart and lung transplantation

Since the 1960s, heart and lung transplantation has remained the optimal therapy for patients with end-stage disease, extending and improving quality of life for thousands of individuals annually. Expanding donor organ availability and immunologic compatibility is a priority to help meet the clinical demand for organ transplant. While effective, current immunosuppression is imperfect as it lacks specificity and imposes unintended adverse effects such as opportunistic infections and malignancy that limit the health and longevity of transplant recipients. In this review, we focus on donor macrophages as a new target to achieve allograft tolerance. Donor organ-directed therapies have the potential to improve allograft survival while minimizing patient harm related to global suppression of recipient immune responses. Topics highlighted include the role of ontogenically distinct donor macrophage populations in ischemia-reperfusion injury and rejection, including their interaction with allograft-infiltrating recipient immune cells and potential therapeutic approaches. Ultimately, a better understanding of how donor intrinsic immunity influences allograft acceptance and survival will provide new opportunities to improve the outcomes of transplant recipients.

Dissecting the Multiplicity of Immune Effects of Immunosuppressive Drugs to Better Predict the Risk of de novo Malignancies in Solid Organ Transplant Patients

De novo malignancies constitute an emerging cause of morbidity after solid organ transplant (SOT), significantly affecting the long-term survival of transplant recipients. Pharmacologic immunosuppression may functionally impair the immunosurveillance in these patients, thereby increasing the risk of cancer development. Nevertheless, the multiplicity and heterogeneity of the immune effects induced by immunosuppressive drugs limit the current possibilities to reliably predict the risk of de novo malignancy in SOT patients. Therefore, there is the pressing need to better characterize the immune dysfunctions induced by the different immunosuppressive regimens administered to prevent allograft rejection to tailor more precisely the therapeutic schedule and decrease the risk of de novo malignancies. We herein highlight the impact exerted by different classes of immunosuppressants on the most relevant immune cells, with a particular focus on the effects on dendritic cells (DCs), the main regulators of the balance between immunosurveillance and tolerance.

The Effect of Immunosuppressive Drugs on MDSCs in Transplantation

Myeloid-derived suppressor cells (MDSCs) are a group of innate immune cells that regulates both innate and adaptive immune responses. In recent years, MDSCs were shown to play an important negative regulatory role in transplant immunology even upstream of regulatory T cells. In certain cases, MDSCs are closely involved in transplantation immune tolerance induction and maintenance. It is known that some immunosuppressant drugs negatively regulate MDSCs but others have positive effects on MDSCs in different transplant cases. We herein summarized our recent insights into the regulatory roles of MDSCs in transplantation specially focusing on the effects of immunosuppressive drugs on MDSCs and their mechanisms of action. Studies on the effects of immunosuppressive drugs on MDSCs will significantly expand our understanding of immunosuppressive drugs on immune regulatory cells in transplantation and offer new insights into transplant tolerance. We hope to emphasize our concern for the negative effects of immunosuppressive agents on MDSCs, which may potentially attenuate the immune tolerance induction in transplanted recipients.

Spleen-derived classical monocytes mediate lung ischemia-reperfusion injury through IL-1β

Ischemia-reperfusion injury, a form of sterile inflammation, is the leading risk factor for both short-term mortality following pulmonary transplantation and chronic lung allograft dysfunction. While it is well recognized that neutrophils are critical mediators of acute lung injury, processes that guide their entry into pulmonary tissue are not well understood. Here, we found that CCR2+ classical monocytes are necessary and sufficient for mediating extravasation of neutrophils into pulmonary tissue during ischemia-reperfusion injury following hilar clamping or lung transplantation. The classical monocytes were mobilized from the host spleen, and splenectomy attenuated the recruitment of classical monocytes as well as the entry of neutrophils into injured lung tissue, which was associated with improved graft function. Neutrophil extravasation was mediated by MyD88-dependent IL-1β production by graft-infiltrating classical monocytes, which downregulated the expression of the tight junction-associated protein ZO-2 in pulmonary vascular endothelial cells. Thus, we have uncovered a crucial role for classical monocytes, mobilized from the spleen, in mediating neutrophil extravasation, with potential implications for targeting of recipient classical monocytes to ameliorate pulmonary ischemia-reperfusion injury in the clinic.

Pharmacodynamic Monitoring of Tacrolimus-Based Immunosuppression in CD14+ Monocytes After Kidney Transplantation

BACKGROUND

Monocytes significantly contribute to ischemia-reperfusion injury and allograft rejection after kidney transplantation. However, the knowledge about the effects of immunosuppressive drugs on monocyte activation is limited. Conventional pharmacokinetic methods for immunosuppressive drug monitoring are not cell type-specific. In this study, phosphorylation of 3 signaling proteins was measured to determine the pharmacodynamic effects of immunosuppression on monocyte activation in kidney transplant patients.

METHODS

Blood samples from 20 kidney transplant recipients were monitored before and during the first year after transplantation. All patients received induction therapy with basiliximab, followed by tacrolimus (TAC), mycophenolate mofetil, and prednisolone maintenance therapy. TAC whole-blood predose concentrations were determined using an antibody-conjugated magnetic immunoassay. Samples were stimulated with phorbol 12-myristate 13-acetate (PMA)/ionomycin, and phosphorylation of p38MAPK, ERK, and Akt in CD14 monocytes was quantified by phospho-specific flow cytometry.

RESULTS

Phosphorylation of p38MAPK and Akt in monocytes of immunosuppressed recipients was lower after 360 days compared with before transplantation in the unstimulated samples [mean reduction in median fluorescence intensity 36%; range -28% to 77% for p-p38MAPK and 20%; range -22% to 53% for p-Akt; P < 0.05]. P-ERK was only decreased at day 4 after transplantation (mean inhibition 23%; range -52% to 73%; P < 0.05). At day 4, when the highest whole-blood predose TAC concentrations were measured, p-p38MAPK and p-Akt, but not p-ERK, correlated inversely with TAC (rs = -0.65; P = 0.01 and rs = -0.58; P = 0.03, respectively).

CONCLUSIONS

Immunosuppressive drug combination therapy partially inhibits monocyte activation pathways after kidney transplantation. This inhibition can be determined by phospho-specific flow cytometry, which enables the assessment of the pharmacodynamic effects of immunosuppressive drugs in a cell type-specific manner.

Peri- and Postoperative Treatment with the Interleukin-1 Receptor Antagonist Anakinra Is Safe in Patients Undergoing Renal Transplantation: Case Series and Review of the Literature

In patients undergoing solid organ transplantation, the presence of an interleukin-1 (IL-1) driven disease may require the addition of IL-1 inhibiting drugs to the standard immunosuppressive regimen to protect against inflammation and negative graft outcome. Three patients undergoing renal transplantation were treated perioperatively with the interleukin-1 receptor antagonist anakinra. Kidney function increased rapidly in all three and the only complications seen were minor infections. In vitro studies report associations between serum and urinary levels of IL-1β and IL-1 receptor antagonist and negative graft outcome, and studies in animals and two small human trials illustrate a possible protective effect of anti-IL-1 therapy after solid organ transplantation. Peri- and postoperative use of anakinra is safe and effective in patients undergoing renal transplantation.

Targeting the Monocyte-Macrophage Lineage in Solid Organ Transplantation

There is an unmet clinical need for immunotherapeutic strategies that specifically target the active immune cells participating in the process of rejection after solid organ transplantation. The monocyte–macrophage cell lineage is increasingly recognized as a major player in acute and chronic allograft immunopathology. The dominant presence of cells of this lineage in rejecting allograft tissue is associated with worse graft function and survival. Monocytes and macrophages contribute to alloimmunity via diverse pathways: antigen processing and presentation, costimulation, pro-inflammatory cytokine production, and tissue repair. Cross talk with other recipient immune competent cells and donor endothelial cells leads to amplification of inflammation and a cytolytic response in the graft. Surprisingly, little is known about therapeutic manipulation of the function of cells of the monocyte–macrophage lineage in transplantation by immunosuppressive agents. Although not primarily designed to target monocyte–macrophage lineage cells, multiple categories of currently prescribed immunosuppressive drugs, such as mycophenolate mofetil, mammalian target of rapamycin inhibitors, and calcineurin inhibitors, do have limited inhibitory effects. These effects include diminishing the degree of cytokine production, thereby blocking costimulation and inhibiting the migration of monocytes to the site of rejection. Outside the field of transplantation, some clinical studies have shown that the monoclonal antibodies canakinumab, tocilizumab, and infliximab are effective in inhibiting monocyte functions. Indirect effects have also been shown for simvastatin, a lipid lowering drug, and bromodomain and extra-terminal motif inhibitors that reduce the cytokine production by monocytes–macrophages in patients with diabetes mellitus and rheumatoid arthritis. To date, detailed knowledge concerning the origin, the developmental requirements, and functions of diverse specialized monocyte–macrophage subsets justifies research for therapeutic manipulation. Here, we will discuss the effects of currently prescribed immunosuppressive drugs on monocyte/macrophage features and the future challenges.

The Effect of Tacrolimus and Mycophenolic Acid on CD14+ Monocyte Activation and Function

Monocytes and macrophages play key roles in many disease states, including cellular and humoral rejection after solid organ transplantation (SOT). To suppress alloimmunity after SOT, immunosuppressive drug therapy is necessary. However, little is known about the effects of the immunosuppressive drugs tacrolimus and mycophenolic acid (MPA) on monocyte activation and function. Here, the effect of these immunosuppressants on monocytes was investigated by measuring phosphorylation of three intracellular signaling proteins which all have a major role in monocyte function: p38MAPK, ERK and Akt. In addition, biological functions downstream of these signaling pathways were studied, including cytokine production, phagocytosis and differentiation into macrophages. To this end, blood samples from healthy volunteers were spiked with diverse concentrations of tacrolimus and MPA. Tacrolimus (200 ng/ml) inhibited phosphorylation of p38MAPK by 30% (mean) in CD14+ monocytes which was significantly less than in activated CD3+ T cells (max 60%; p < 0.05). This immunosuppressive agent also partly inhibited p-AKT (14%). MPA, at a therapeutic concentration showed the strongest effect on p-AKT (27% inhibition). p-ERK was inhibited with a maximum of 15% after spiking with either tacrolimus or MPA. The production of IL-1β and phagocytosis by monocytes were not affected by tacrolimus concentrations, whereas MPA did inhibit IL-1β production by 50%. Monocyte/macrophage polarization was shifted to an M2-like phenotype in the presence of tacrolimus, while MPA increased the expression of M2 surface markers, including CD163 and CD200R, on M1 macrophages. These results show that tacrolimus and MPA do not strongly affect monocyte function, apart from a change in macrophage polarization, to a clinically relevant degree.

Effects of mycophenolate mofetil on kidney function and phosphorylation status of renal proteins in Alport COL4A3-deficient mice

Background

We investigated the effects of mycophenolate mofetil (MMF) on kidney function and on protein phosphorylation in a mouse model for the human Alport syndrome.

Methods

COL4A3-deficient (COL4A3−/−) mice were randomly allocated to receive a placebo (PLC COL4A3−/−) or MMF treatment (MMF COL4A3−/−). Wild type mice (WT) were used as controls. Changes in serum creatinine, total protein and blood urea nitrogen (BUN), concentrations of mycophenolic acid (MPA) and its glucuronide metabolite (MPAG), serum protein electrophoresis, urine dipstick chemistry and sediment were measured. Changes in the phosphorylation status of renal proteins and histology were analyzed.

Results

MMF influenced kidney function and protein phosphorylation. Serum creatinine and BUN were lower in MMF treated compared to PLC treated COL4A3−/− mice. Serum albumin and alpha-1 globulins were significantly decreased while serum creatinine, alpha-2 globulins, urine dipstick protein, leukocyte esterase, hemoglobin and red blood cells were all increased in both COL4A3−/− groups compared to WT. Differential 2DE-gel analysis identified six phosphorylated kidney protein spots that were significantly altered by MMF.

Conclusions

These data suggest that the MMF treatment in this murine model moderately improved kidney function and reversed the phosphorylation status of six renal phosphoprotein spots to that seen in WT mice.

Electronic supplementary material

The online version of this article (doi:10.1186/s12953-014-0056-z) contains supplementary material, which is available to authorized users.

Moderate-dose glucocorticoids as salvage therapy for severe pneumonia in renal transplant recipients: a single-center feasibility study

This study aimed to assess the effectiveness and safety of moderate-dose glucocorticoids (GCs) with mechanical ventilation as salvage therapy for renal transplant recipients with severe pneumonia, which was non-responsive to conventional treatment. A retrospective study was conducted involving renal transplant recipients diagnosed with severe pneumonia and did not respond to conventional treatment. All immunosuppressants were then completely withdrawn, and the patients were initially administered with methylprednisolone at doses of 2.0-2.5 mg/kg/day once every 12 h. This dosage was continued until oxygenation improved, and the treatment was gradually tapered (by 20 mg every 2-3 days) to the previous maintenance dosage. Ten patients were recruited from year 2008 to 2012. Two patients who underwent emergency endotracheal intubation were intubated on days 3 and 8, respectively, another one died from recurrent pneumothorax. The mean PaO2/FiO2 of the nine survivors was significantly increased by the increasing treatment duration; whereas the lung injury scores (LIS) and the sequential organ failure assessment (SOFA) score were both significantly decreased. The use of moderate-dose GCs may play a role as salvage therapy for renal transplant recipients with severe pneumonia. However, further study with larger trials to is needed.

Evidence of an anti-inflammatory effect of mycophenolate mofetil in a murine model of pleurisy

A promising therapeutic approach to reducing inflammation is to inhibit the production of proinflammatory cytokines (e.g., tumor necrosis factor alpha [TNF-α], interleukin 1 beta [IL-1β], vascular endothelial growth factor alpha (VEGF-α), and, as shown more recently, interleukin-17 [IL-17]). In the present study, the authors have demonstrated the anti-inflammatory effects of mycophenolate mofetil (MMF) in in vivo experiments and have investigated the mechanism of action underlying those effects. Oral administration of MMF significantly inhibited leukocyte influx during the first (4 hours) and second (48 hours) phases of inflammation in a mouse model of pleurisy caused by carrageenan (P < .01). As expected, MMF suppressed protein levels of TNF-α, IL-1β, VEGF-α, and IL-17A (P < .01). This inhibitory effect was due to down-regulation of mRNA expression for these proinflammatory cytokines (P < .01). These results provide evidence of MMF-mediated inhibition of proinflammatory cytokines, and these anti-inflammatory effects are assumed to result mainly from the inhibition of the synthesis and release of TNF-α, IL-1β, VEGF-α, and IL-17A from activated leukocytes. These findings suggest that MMF might be an applicable therapeutic in the regulation of the inflammatory response-a response in which the humoral system plays a pivotal role.

Inhibition of mTOR blocks the anti-inflammatory effects of glucocorticoids in myeloid immune cells

A central role for the mammalian target of rapamycin (mTOR) in innate immunity has been recently defined by its ability to limit proinflammatory mediators. Although glucocorticoids (GCs) exert potent anti-inflammatory effects in innate immune cells, it is currently unknown whether the mTOR pathway interferes with GC signaling. Here we show that inhibition of mTOR with rapamycin or Torin1 prevented the anti-inflammatory potency of GC both in human monocytes and myeloid dendritic cells. GCs could not suppress nuclear factor-κB and JNK activation, the expression of proinflammatory cytokines, and the promotion of Th1 responses when mTOR was inhibited. Interestingly, long-term activation of monocytes with lipopolysaccharide enhanced the expression of TSC2, the principle negative regulator of mTOR, whereas dexamethasone blocked TSC2 expression and reestablished mTOR activation. Renal transplant patients receiving rapamycin but not those receiving calcineurin inhibitors displayed a state of innate immune cell hyper-responsiveness despite the concurrent use of GC. Finally, mTOR inhibition was able to override the healing phenotype of dexamethasone in a murine lipopolysaccharide shock model. Collectively, these data identify a novel link between the glucocorticoid receptor and mTOR in innate immune cells, which is of considerable clinical importance in a variety of disorders, including allogeneic transplantation, autoimmune diseases, and cancer.

Genetic polymorphisms influence mycophenolate mofetil-related adverse events in pediatric heart transplant patients

BACKGROUND

Mycophenolate mofetil (MMF) is an effective and commonly used immunosuppressant but has frequent adverse events. Genetic polymorphisms may contribute to variability in MMF efficacy and related complications. In this study we explore the distribution frequencies of common single nucleotide polymorphisms (SNPs) of IMPDH1, IMPDH2 and ABCC2 and investigate whether these SNPs influence MMF adverse events in 59 pediatric heart recipients.

METHODS

Genotypes were assessed by TaqMan analysis of: ABCC2 rs717620; IMPDH2 rs11706052; and IMPDH1 rs2288553, rs2288549, rs2278293, rs2278294 and rs2228075. Gastrointestinal (GI) intolerance was defined as diarrhea, vomiting, nausea or abdominal pain requiring dose-holding for >48 hours or MMF discontinuation. Bone marrow toxicity was evaluated using Common Terminology Criteria for Adverse Events Version 3 (CTCAE).

RESULTS

GI intolerance occurred in 21 patients, and 21 had bone marrow toxicity. The ABCC2 rs717620 A variant was significantly associated with GI intolerance leading to drug discontinuation (p < 0.001); the IMPDH1 rs2278294 A variant and rs2228075 A variant were also associated with greater GI intolerance (p = 0.029 and p = 0.002, respectively). The IMPDH2 rs11706052 G variant was associated with more frequent neutropenia requiring dose-holding (p = 0.046).

CONCLUSIONS

In this small sample of pediatric heart transplant patients receiving MMF, ABCC2, IMPDH1 and IMPDH2 SNPs were associated with MMF GI intolerance and bone marrow toxicity. Thus, genetic polymorphisms may directly influence MMF adverse events.

Mycophenolate mofetil prevents lethal acute liver failure in mice induced by bacille Calmette-Guérin and lipopolysaccharide

BACKGROUND/AIMS

To investigate the effect of mycophenolate mofetil (MMF) on acute liver injury induced by bacille Calmette-Guérin (BCG) and lipopolysaccharide (LPS).

METHODS

Acute liver failure was induced in male Kunming strain mice by injecting the animals with BCG 2.5 mg per mouse, and LPS 10 microg per mouse 10 days later. The mice in the treatment groups were given MMF 2 h before, simultaneous with, or 2 h after administration of LPS, and the mice in the control group were given the same dose of saline. The 24-h survival rate, serum alanine aminotransferase (ALT), and aspartate aminotransferase (AST) levels were compared. Serum levels of tumor necrosis factor alpha (TNF-alpha), interferon gamma (IFN-gamma), and interleukin 6 (IL-6) were measured and the expressions of TNF-alpha, IFN-gamma, and IL-6 mRNA in the liver tissue were determined by reverse transcription-polymerase chain reaction (RT-PCR). Concanavalin A (Con A)-induced splenocyte proliferation were determined by methods of methyl thiazolyl tetrazolium.

RESULTS

Injecting a small dose of LPS into BCG-primed mice caused a lethal hepatic injury mimicking acute hepatitis, from which 16 of the 20 mice died within 24 h (20% survival rate). Massive necrosis of parenchymal hepatocytes with marked inflammatory cell infiltration was observed by histological examination. In parallel, serum ALT and TNF-alpha, IFN-gamma, and IL-6 levels were increased. Expression of TNF-alpha, IFN-gamma, and IL-6 mRNA in the liver were significantly increased also. Treatment with MMF markedly reduced the death rate in a dose-dependent manner. It reached its maximal effect at the dosage of 150 mg per kg of body weight when pretreated 2 h before LPS injection, with improvement of histological feather and survival rate (84.2%, 16/19). MMF significantly inhibited serum levels of TNF-alpha, IFN-gamma, and IL-6, and significantly reduced TNF-alpha, IFN-gamma, and IL-6 expression in the liver, which increased after BCG and LPS injection. Moreover, splenocyte proliferation response induced by Con A was also inhibited by MMF treatment.

CONCLUSIONS

Treatment with MMF has a protective effect on endotoxin-induced fatal liver failure by regulating the production of inflammatory cytokines and T-cell proliferation.

Post-transplant sCD30 and neopterin as predictors of chronic allograft nephropathy: impact of different immunosuppressive regimens

Immunological monitoring for chronic allograft nephropathy (CAN) is of great potential interest. We assessed serum soluble CD30 (sCD30) together with in vitro Th2-type responses (IL-4, IL-10, CD4 helper activity) and neopterin in a prospective study of 84 renal transplant recipients with 2-year follow-up. Patients were randomized to CsA/Aza, CsA/MMF and Tacr/Aza, respectively, to analyze the effect of immunosuppression on posttransplant sCD30 and neopterin. ATG induction and acute rejections did not alter sCD30 levels whereas CMV disease was associated with transient upregulation of sCD30 (p = 0.003 at 4 months) and sustained upregulation of neopterin (corrected for graft function (Neo/CR) p = 0.005 at 2 years). Tacr versus CsA treatment proved to be an independent variable associated with downregulation of 1-year sCD30, which was positively related to Neo/CR (p = 0.007 and 0.01, respectively; logistic regression). Importantly, increased 1-year sCD30 and Neo/CR were associated with decreased glomerular filtration rate at 2 years (p = 0.02 and p < 0.0005, respectively) and evidence of CAN (p < 0.0005). High 1-year sCD30 could not be attributed to enhanced Th2-type responses and was not associated with HLA antibody formation. Our data suggest that elevated sCD30 and neopterin predict graft deterioration by CAN. Tacr effectively downregulates these responses and might be of advantage in patients with elevated sCD30 or neopterin.

IL-6 Promoter Polymorphism −174 Is Associated with New-Onset Diabetes after Transplantation

New-onset diabetes after transplantation (NODAT) is a serious complication of transplantation. This study tested whether IL-6 production capacity may influence the development of NODAT in two different groups of patients. The occurrence of NODAT was analyzed with respect to IL-6 gene promoter polymorphism at position -174 (G-->C) and other relevant risk factors retrospectively in 217 renal transplant recipients and prospectively in 132. A linear increase in both circulating IL-6 (P = 0.09) and C-reactive protein (an indicator of basal IL-6 secretion; P = 0.03) concentrations from the CC genotype to the GG genotype was observed. In the multivariate model, the CC genotype was associated with a decreased risk for NODAT compared with the GG genotype in the two cohorts. Homeostasis Model Assessment for Insulin Resistance also revealed lesser insulin sensitivity in the GG carriers than in the CC carriers (2.15 +/- 2 versus 1.32 +/- 1.03; P = 0.03). Subgroup analysis showed that the influence of IL-6 gene promoter polymorphism on the development of NODAT was restricted mostly to overweight patients. These results highly suggest that IL-6 production capacity influences the development of NODAT and that diabetes-inducing drug administration should be limited in overweight patients who carry the GG genotype.

Urine Cytokines Profile in Renal Transplant Patients with Asymptomatic Bacteriuria

BACKGROUND

The role of asymptomatic bacteriuria in kidney transplant recipients is unknown. There is no clear evidence of its effect on transplanted kidney.

METHODS

We studied urine cytokines profile among kidney transplant recipients with bacteriuria found in screening examination. Urine cultures were collected in 269 patients with stable graft function and serum creatinine level <2 mg/dl, during their routine visits. Interleukin (IL)-6 and IL-8 levels were measured in urine samples from patients with asymptomatic bacteriuria, symptomatic urinary tract infection and patients without bacteriuria (control group). Changes in serum creatinine level in patients with asymptomatic bacteriuria and in the control group were observed during 12 months follow up.

RESULTS

Urinary tract infection (UTI) was diagnosed in five patients and asymptomatic bacteriuria in 22 patients. Urine IL-6 level was significantly higher in symptomatic UTI group (median 15.71 pg/mg) but there were no differences between group of patients with asymptomatic bacteriuria (3.92 pg/mg) and control group (2.54 pg/mg). Urine IL-8 level was higher in symptomatic UTI group (median 146.8 pg/mg) and was also significantly higher in asymptomatic bacteriuria group (33.49 pg/mg) in comparison to control group (2.97 pg/mg; P=0.0002). During 1-year follow up, incidence of UTI was higher in the asymptomatic bacteriuria group than in the control group but graft function was not different in both groups.

CONCLUSIONS

Elevated urine IL-8 level in kidney transplant patients with asymptomatic bacteriuria may reflect impaired immune response to bacterial infection and occult inflammatory process in urinary tract.

The Relative Importance of Cytokine Gene Polymorphisms in the Development of Early and Late Acute Rejection and Six-Month Renal Allograft Pathology

BACKGROUND

Acute rejection episodes and 6-month protocol biopsy acute pathology are highly correlated with long-term outcomes in renal transplant recipients. Recurrent, vascular, and late rejections are particularly deleterious.

METHODS

We determined the relative contribution of human leukocyte antigen matching, cytokine genotypes, delayed graft function (DGF), and baseline immunosuppression to the development of acute rejection and allograft pathology in 118 renal transplant recipients.

RESULTS

Multivariate logistic regression modeling demonstrated that the adjusted odds ratio and 95% confidence interval for recurrent (> or =2) early rejections (0-3 months) increased linearly for high (H) > intermediate (I) > low (L) interferon-gamma (1.8; 1.1-3.2) and tumor necrosis factor (TNF)alpha (3.0; 1.3-6.9) genotype, whereas every 1 microg/L increase in the cyclosporine A level was protective (0.991; 0.984-0.999). The odds ratio for recurrent late rejections (4-6 months) increased for H > I > L TNFalpha (5.1; 1.8-14.7) genotype and DGF (7.1; 1.6-30.2), whereas H > I/L transforming growth factor-beta1 genotype decreased the relative risk (0.09: 0.02-0.49). Vascular rejection was only predicted by H > I > L TNFalpha phenotype (3.0; 1.2-7.9). The odds ratio for the 6-month Banff Acute Score (6A > or= 4) increased for H > I > L TNFalpha (2.7; 1.1-6.7) and interleukin-10 (3.4; 1.2-6.2) genotype, and DGF (3.4; 1.1-11.5). Treatment of early subclinical rejection decreased the relative risk (0.20; 0.07-0.62).

CONCLUSIONS

High transforming growth factor-beta1 producer phenotype seems to be protective against acute inflammation, whereas H and I interferon-gamma, TNFalpha, and interleukin-10 producer genotypes correlate with adverse outcomes. Cytokine genotyping identifies individuals who may benefit from more intensive surveillance and treatment posttransplant.

Cytokine Gene Polymorphisms and Risks of Acute Rejection and Delayed Graft Function after Kidney Transplantation

BACKGROUND

Pretransplantation identification of patients at an increased risk for adverse events would allow more individualized treatment strategies possibly improving long-term outcome. We studied cytokine gene polymorphisms of kidney allograft recipients and their donors to identify factors predisposing for acute rejection (AR) and delayed graft function (DGF).

METHODS

A total of 291 adult cadaver kidney recipients transplanted at a single transplantation centre between 1999 and 2002 were investigated. Recipients and donors were typed for TNF-alpha(-308G/A), TGF-beta1(codon 10T/C, codon 25C/G), IL-10(-1082G/A, -819C/T, -592C/A), IL-6(-174C/G), and IFN-gamma(+874T/A) polymorphisms using a SSP-PCR kit. An AR episode was defined based on clinical and histological findings (Banff criteria). RESULTS.: The incidence of AR was 17%. In univariate statistical analyses recipients with TNF-alpha -308AA-genotype were found to be at a significantly increased risk for rejection (odds ratio [OR] 5.0, 95% CI 3.0-8.3, P = 0.003). The association was independent from the patient-donor HLA-mismatch status. In addition, patients with IL-10 ACCACC, ATAATA, GCCATA (-1082A/G, -819C/T, -592C/A, respectively) haplotypes were predisposed to rejection (OR 1.9, 95% CI 1.1-3.1, P = 0.016). Further, the combination of recipient TGF-beta1 25GG-genotype and donor IL-10 -819T-allele was associated with rejection (OR 1.8, 95% CI 1.1-3.0, P = 0.027). These variables remained significant risk factors also in a multivariate logistic regression analysis. The incidence of DGF was 22%. The risk was increased by a donor TNF-alpha -308GA-genotype (OR 1.6, 95% CI 1.1-2.6, P = 0.040).

CONCLUSIONS

Our results confirm that cytokine gene polymorphisms influence the outcome of kidney transplantation. Our data especially identify the TNF-alpha -308AA-genotype as a factor predisposing for AR episodes.

Review of the immunosuppressant enteric-coated mycophenolate sodium

Enteric-coated mycophenolate sodium (EC-MPS; myfortic, Novartis Pharma AG) is an advanced formulation delivering mycophenolic acid (MPA). EC-MPS was designed to improve MPA-related upper gastrointestinal adverse events by delaying the release of MPA until reaching the small intestine. At a dose of 720 mg, EC-MPS exhibits equivalent MPA exposure (area under the concentration curve [AUC]) and maximal MPA concentration (C(max)) to mycophenolate mofetil (MMF; CellCept, Roche AG) 1000 mg. The time to maximal MPA concentration (T(max)) for EC-MPS is delayed relative to that for MMF, consistent with a functioning enteric coating. EC-MPS 720 mg b.i.d. has demonstrated therapeutic equivalence to MMF 1000 mg b.i.d. in renal transplant patients. Recent clinical trials have demonstrated that EC-MPS is as effective and safe as MMF in both de novo and maintenance renal transplant patients. Furthermore, studies have confirmed that maintenance patients can be safely converted from MMF to EC-MPS with no compromise of efficacy or safety. EC-MPS therefore presents physicians and patients with a valid alternative MPA therapy with a comparable efficacy and safety profile to MMF.

Mycophenolate mofetil and reduced doses of cyclosporine in pediatric liver transplantation with chronic renal dysfunction: changes in the immune responses

The aim of this study was to study the incidence of chronic renal dysfunction in patients with more than 5 yr of follow-up following liver transplantation and to evaluate the benefit of decreasing cyclosporine A (CsA) dose combined with mycophenolate mofetil (MMF) on renal function and immune response in these patients. Between 1988 and 1994, 60 children were transplanted, and 86% survived >5 yr post-liver transplantation. Fourteen patients developed chronic renal dysfunction secondary to CsA toxicity as evaluated by renal biopsy. In 11 patients CsA dose was decreased to 40-90 mg/ml target levels and MMF 600 mg/m(2) twice daily was added to the immunosuppressive regimen. Plasma creatinine decreased (from 1.0 +/- 0.03 to 0.8 +/- 0.03 ng/dl, p < 0.007), creatinine clearance increased (from 66.8 +/- 3.0 to 99.2 +/- 6.3 ml/min/1.73 m(2), p < 0.002) and microalbuminuria decreased (from 21.0 +/- 8.6 to 3.6 +/- 1.1 mg/24 h, p < 0.05) after 12 months of CsA combined with MMF therapy. During combined therapy the proliferative, cytolytic response and cytotoxic antibodies showed no significant changes, whereas CD4/CD8 ratio increased (from 1.2 +/- 0.2 to 1.4 +/- 0.1, p < 0.05). Tumor necrosis factor-alpha secretion increased (p < 0.005) during MMF therapy. The release of interleukin-10 was strikingly augmented under both immunosuppressive regimens, but the release of transforming growth factor-beta and interferon-gamma did not change. Our findings indicate that initiation of MMF combined with reduced doses of CsA allowed the recovery of renal function with minor changes in the immune response.