Disturbances of acquired immunity in hemodialysis patients

Controlling Time-Dependent Confounding by Health Status and Frailty: Restriction Versus Statistical Adjustment

Nonexperimental studies of preventive interventions are often biased because of the healthy-user effect and, in frail populations, because of confounding by functional status. Bias is evident when estimating influenza vaccine effectiveness, even after adjustment for claims-based indicators of illness. We explored bias reduction methods while estimating vaccine effectiveness in a cohort of adult hemodialysis patients. Using the United States Renal Data System and linked data from a commercial dialysis provider, we estimated vaccine effectiveness using a Cox proportional hazards marginal structural model of all-cause mortality before and during 3 influenza seasons in 2005/2006 through 2007/2008. To improve confounding control, we added frailty indicators to the model, measured time-varying confounders at different time intervals, and restricted the sample in multiple ways. Crude and baseline-adjusted marginal structural models remained strongly biased. Restricting to a healthier population removed some unmeasured confounding; however, this reduced the sample size, resulting in wide confidence intervals. We estimated an influenza vaccine effectiveness of 9% (hazard ratio = 0.91, 95% confidence interval: 0.72, 1.15) when bias was minimized through cohort restriction. In this study, the healthy-user bias could not be controlled through statistical adjustment; however, sample restriction reduced much of the bias.

Crosstalk between peroxisome proliferator-activated receptor-γ and mineralcorticoid receptor in TNF-α activated renal tubular cell

INTRODUCTION

In our previous study, we observed the crosstalk between peroxisome proliferator-activated receptor-γ (PPAR-γ) and angiotensin II in activated renal tubular cells. The present study is aimed to further explore the crosstalk between PPAR-γ and mineralocorticoid receptor (MR) in tumor necrosis factor (TNF)-α activated renal tubular cells.

METHODS

Human proximal renal tubular epithelial cells HK-2 were cultured with the pre-treatment of PPAR-γ agonist, pioglitazone (5 μM), MR antagonist, eplerenone (5 μM), or their combined treatment, followed by activation with TNF-α (20 ng/ml). In the parallel experiment, PPAR-γ inhibitor GW9662 (25 µM) was used to study the independence of PPAR-γ. Gene expression and protein synthesis of intercellular adhesion molecule-1 (ICAM-1), interleukin-6 (IL-6), MR and PPAR-γ were measured by RT-PCR, ELISA and Western blot, respectively; nuclear factor κB (NF-κB) nuclear translocation activity in the nucleus was examined by EMSA assay.

RESULTS

TNF-α effectively activated HK-2 cells by up-regulating gene expression and protein synthesis of ICAM-1, IL-6 and MR and down-regulating PPAR-γ in a dose-dependent manner. TNF-α also significantly induced NF-κB nuclear translocation in HK-2 cells. Dual treatment of pioglitazone and eplerenone demonstrated synergistic effect on reducing ICAM-1 and IL-6 expression and alleviating NF-κB activation when compared with their monotherapies in TNF-α activated renal tubular cells. PPAR-γ antagonist, GW9662, significantly attenuated protective effect on ICAM-1, IL-6 and PPAR-γ expression by pioglitazone, eplerenone and their combined treatment.

CONCLUSIONS

Our data suggest that pioglitazone, in a PPAR-γ-dependent manner, trans-represses MR signaling by suppressing NF-κB activation. MR antagonist also restored PPAR-γ expression. Dual treatment of pioglitazone and eplerenone present better efficacy in attenuating excessive inflammatory response in activated renal tubular cells under stimulation of TNF-α than single treatment.

Hepatitis C in hemodialysis patients

Despite reduction of hepatitis C prevalence after recognition of the virus and testing of blood products, hemodialysis (HD) patients still comprise a high risk group. The natural history of hepatitis C virus (HCV) infection in dialysis is not fully understood while the clinical outcome differs from that of the general population. HD patients show a milder liver disease with lower aminotransferase and viral levels depicted by milder histological features on liver biopsy. Furthermore, the “silent” clinical course is consistent with a slower disease progression and a lower frequency of cirrhosis and hepatocellular carcinoma. Potential explanations for the “beneficial” impact of uremia and hemodialysis on chronic HCV infection are impaired immunosurveillance leading to a less aggressive host response to the virus and intradialytic release of “hepatoprotective” cytokines such as interferon (IFN)-α and hepatocyte growth factor. However, chronic hepatitis C is associated with a higher liver disease related cardiovascular and all-cause mortality of HD patients. Therapy is indicated in selected patients groups including younger patients with low comorbidity burden and especially renal transplant candidates, preferably after performance of a liver biopsy. According to current recommendations, choice of treatment is IFN or pegylated interferon with a reported sustained viral response at 30%-40% and a withdrawal rate ranging from 17% to 30%. New data regarding combination therapy with low doses of ribavirin which provide higher standard variable rates and good safety results, offer another therapeutic option. The new protease inhibitors may be the future for HCV infected HD patients, though data are still lacking.

The risk of hospitalization and modality failure with home dialysis

While home dialysis is being promoted, there are few comparative effectiveness studies of home-based modalities to guide patient decisions. To address this, we matched 1116 daily home hemodialysis (DHD) patients by propensity scores to 2784 contemporaneous USRDS patients receiving home peritoneal dialysis (PD), and compared hospitalization rates from cardiovascular, infectious, access-related or bleeding causes (prespecified composite), and modality failure risk. We performed similar analyses for 1187 DHD patients matched to 3173 USRDS patients receiving in-center conventional hemodialysis (CHD). The composite hospitalization rate was significantly lower with DHD than with PD (0.93 vs. 1.35/patient-year, hazard ratio=0.73 (95% CI=0.67–0.79)). DHD patients spent significantly fewer days in hospital than PD patients (5.2 vs. 9.2 days/patient-year), and significantly more DHD patients remained admission-free (52% DHD vs. 32% PD). In contrast, there was no significant difference in hospitalizations between DHD and CHD (DHD vs. CHD: 0.93 vs. 1.10/patient-year, hazard ratio 0.92 (0.85–1.00)). Cardiovascular hospitalizations were lower with DHD than with CHD (0.68 (0.61–0.77)), while infectious and access hospitalizations were higher (1.15 (1.04–1.29) and 1.25 (1.08–1.43), respectively). Significantly more PD than DHD patients switched back to in-center HD (44% vs. 15% 3.4 (2.9–4.0)). In this prevalent cohort, home DHD was associated with fewer admissions and hospital days than PD, and a substantially lower risk of modality failure.

Serum vitamin D levels are positively associated with varicella zoster immunity in chronic dialysis patients

Uremia results in a relatively immunocompromised status, and patients under chronic dialysis have an elevated risk of developing herpes zoster (HZ). We sought to investigate the relationship between vitamin D status and immunity to varicella-zoster virus (VZV). A multicenter prevalent hemodialysis cohort was assembled between 2012 and 2013. We assayed the biochemical parameters, 25-hydroxy- (25-OH-D) and 1,25-dihydroxyvitamin D, vitamin D-binding protein levels in the sera. VZV immunity was quantitated using VZV-specific glycoprotein IgG and IgM titers. Eighty-eight patients were enrolled and their sera were analyzed. Chronic hemodialysis patients with 25-OH-D < 30 ng/ml (insufficiency or deficiency) had significantly lower VZV-IgG than those with sufficient 25-OH-D (p = 0.04). This discrepancy became more prominent if active vitamin D users alone were analyzed (p = 0.01). Generalized additive modeling showed that those with 25-OH-D higher than 27.8 ng/ml or bioavailable 25-OH-D higher than 3.88 ng/ml had significantly higher VZV-IgG levels than those with lower values. Linear regression suggested that both total and bioavailable 25-OH-D were significantly associated with higher VZV-IgG levels (p = 0.003 [total] and 0.01 [bioavailable]), whereas patients with cancer had lower VZV-IgG. Vitamin D may therefore be a potentially useful choice for raising VZV immunity in chronic dialysis patients.

Biology of sepsis: its relevance to pediatric nephrology

Because of its multi-organ involvement, the syndrome of sepsis provides clinical challenges to a wide variety of health care providers. While multi-organ dysfunction triggered by sepsis requires general supportive critical care provided by intensivists, the impact of sepsis on renal function and the ability of renal replacement therapies to modulate its biologic consequences provide a significant opportunity for pediatric nephrologists and related care providers to impact outcomes. In this review, we aim to highlight newer areas of understanding of the pathobiology of sepsis with special emphasis on those aspects of particular interest to pediatric nephrology. As such, we aim to: (1) review the definition of sepsis and discuss advances in our mechanistic understanding of sepsis; (2) review current hypotheses regarding sepsis-induced acute kidney injury (AKI) and describe its epidemiology based on evolving definitions of AKI; (3) review the impact of renal failure on the immune system, highlighting the sepsis risk in this cohort and strategies that might minimize this risk; (4) review how renal replacement therapeutic strategies may impact sepsis-induced AKI outcomes. By focusing the review on these specific areas, we have omitted other important areas of the biology of sepsis and additional interactions with renal function from this discussion; however, we have aimed to provide a comprehensive list of references that provide contemporary reviews of these additional areas.

Parasites and chronic renal failure

Suppression of the human immune system results in an increase in susceptibility to infection by various infectious agents. Conditions such as AIDS, organ transplantation and chronic renal insufficiency (CRI) are the most important cause of insufficient immune response against infections. Long term renal disorders result in uremia, which can suppress human immune system. Parasitic infections are one of the most important factors indicating the public health problems of the societies. These infections can be more hostile and life threatening in susceptible individuals than in the normal people. In these patients some parasitic infections such as blastocystiosis, cryptosporidiosis and toxoplasmosis have been reported to be more prevalent. This review aimed to give an overview about parasitic infections in patients with renal disorders.

Rates of and Factors Associated With Infection in 200 909 Medicare Implantable Cardioverter-Defibrillator Implants

Background—

The rate of implantable cardioverter-defibrillator (ICD) infections has been increasing faster than that of implantation. We sought to determine the rate and predictors of ICD infection in a large cohort of Medicare patients.

Methods and Results—

Cases submitted to the ICD Registry from 2006 to 2009 were matched to Medicare fee-for-service claims data using indirect patient identifiers. ICD infections occurring within 6 months of hospital discharge after implantation were identified by ICD-9 codes. Logistic regression was used to examine factors associated with risk of ICD infection. Of 200 909 implants, 3390 patients (1.7%) developed an ICD infection. The infection rate was 1.4%, 1.5%, and 2.0% for single, dual, and biventricular ICDs, respectively ( P <0.001). Generator replacement had a higher rate compared with initial implant (1.9% versus 1.6%, P <0.001). The factors associated with infection were adverse event during implant requiring reintervention (odds ratio [OR], 2.692; 95% confidence interval [CI], 2.304–3.145), previous valvular surgery (OR, 1.525; 95% CI, 1.375–1.692), reimplantation for device upgrade, malfunction, or manufacturer advisory (OR, 1.354; 95% CI, 1.196–1.533), renal failure on dialysis (OR, 1.342; 95% CI, 1.123–1.604), chronic lung disease (OR, 1.215; 95% CI, 1.125–1.312), cerebrovascular disease (OR, 1.172; 95% CI, 1.076–1.276), and warfarin (OR, 1.155; 95% CI, 1.060–1.257).

Conclusions—

Patients who developed an ICD infection were more likely to have had peri-ICD implant complications requiring early reintervention, previous valve surgery, device replacement for reasons other than battery depletion, and increased comorbidity burden. Efforts should be made to carefully consider when to reenter the pocket at any time other than battery replacement.

Factors affecting effectiveness of vaccination against hepatitis B virus in hemodialysis patients

Hepatitis B virus (HBV) is a major global health problem. Despite the success of the general measures against blood transmitted infections in hemodialysis (HD) units, the prevalence of HBV infection among the HD patients is still high. Thus vaccination against HBV is indicating in this population. However, compared with the general population the seroprotection achieved in HD patients remains relatively low, at about 70%. In this review patient, HD procedure and vaccine-associated factors that affect the efficacy of HBV vaccination are analyzed. Also alternative routes of HBV vaccine administration as well as new and more immunogenic vaccine formulations are discussed. However, besides scientific progress, vigilance of HD physicians and staff regarding the general measures against the transmission of blood borne infections and the vaccination against HBV is also required for reducing the prevalence of this viral infection.

Alterations of intestinal barrier and microbiota in chronic kidney disease

Recent studies have highlighted the close relationship between the kidney and the gastrointestinal (GI) tract--frequently referred to as the kidney--gut axis--in patients with chronic kidney disease (CKD). In this regard, two important pathophysiological concepts have evolved: (i) production and accumulation of toxic end-products derived from increased bacterial fermentation of protein and other nitrogen-containing substances in the GI tract, (ii) translocation of endotoxins and live bacteria from gut lumen into the bloodstream, due to damage of the intestinal epithelial barrier and quantitative/qualitative alterations of the intestinal microbiota associated with the uraemic milieu. In both cases, these gut-centred alterations may have relevant systemic consequences in CKD patients, since they are able to trigger chronic inflammation, increase cardiovascular risk and worsen uraemic toxicity. The present review is thus focused on the kidney-gut axis in CKD, with special attention to the alterations of the intestinal barrier and the local microbiota (i.e. the collection of microorganisms living in a symbiotic coexistence with their host in the intestinal lumen) and their relationships to inflammation and uraemic toxicity in CKD. Moreover, we will summarize the most important clinical data suggesting the potential for nutritional modulation of gut-related inflammation and intestinal production of noxious by-products contributing to uraemic toxicity in CKD patients.

Serum copper and ferroportin in monocytes of hemodialysis patients are both decreased but unassociated

PURPOSE

Disturbed iron homeostasis contributes to resistance to recombinant human erythropoietin (rHuEpo) in hemodialysis (HD) patients. Although increased hepcidin, which downregulates the iron exporter ferroportin, had been incriminated, such an association has not been confirmed. Albeit not universally accepted, it has been supported that in case of copper deficiency, decreased activity of multicopper oxidases induces endocytosis and degradation of ferroportin. Ferroportin in monocytes, serum copper, ceruloplasmin and markers of iron status were measured, and associations with rHuEpo resistance index (ERI) were evaluated.

METHODS

After a 4-week washout period from iron treatment, 34 HD patients and 20 healthy volunteers enrolled in the study. Ferroportin was assessed by means of Western blotting, copper colorimetrically, whereas ceruloplasmin with enzyme-linked immunosorbent assay. Hemoglobin, serum iron, ferritin and transferrin saturation (TSAT) were also measured.

RESULTS

Ferroportin in monocytes of HD patients was decreased. Serum copper, ceruloplasmin, iron and TSAT were decreased. No correlation between copper or ceruloplasmin and ferroportin was detected. ERI was negatively correlated with ferroportin and all the markers of iron adequacy, but not with copper or ceruloplasmin.

CONCLUSION

Although copper deficiency and decreased ferroportin are common in HD patients, copper might not play role in ferroportin level in monocytes and in iron metabolism in this population.

Problems associated with hemodialysis and travel

BACKGROUND

While there is a recognized risk of hepatitis C acquisition associated with dialysis away from the "home" center, there is little documented data on the effect that dialysis while traveling has on the dialysis patient's health. This study was designed to examine the incidence of travel within a hemodialysis population and to ascertain whether travel was associated with morbidity for patients on hemodialysis.

METHODS

Travel data were collected prospectively over a 6-month period, from April 2009, for all patients receiving maintenance hemodialysis across our dialysis centers. Biochemical, microbiological, and hematological parameters as well as hepatitis serology and antibiotic starts were recorded for 12 weeks prior to and following dialysis away from center.

RESULTS

A total of 172 individuals traveled on 200 occasions. The blood stream infection rate for travelers with a central venous catheter was 0.25 versus 0.83/1,000 access days (p = 0.038) in the 12 weeks pre-travel versus post-travel. Parenteral and oral antibiotic starts were both significantly elevated post-travel and were mainly instituted for either chest or urinary sepsis. There was evidence of raised inflammatory markers and anemia on return to center but no evidence of hepatitis B or hepatitis C seroconversion.

CONCLUSIONS

Travel and dialysis away from a patient's usual hemodialysis unit is a common occurrence but is associated with an increased risk of bacterial infection, anemia, and inflammatory response. This study provides evidence for the concern that hemodialysis away from center is associated with increased morbidity.

Costimulatory pathways in kidney transplantation: pathogenetic role, clinical significance and new therapeutic opportunities

Costimulatory pathways play a key role in immunity, providing the second signal required for a full activation of adaptive immune response. Different costimulatory families (CD28, TNF-related, adhesion and TIM molecules), characterized by structural and functional analogies, have been described. Costimulatory molecules modulate T cell activation, B cell function, Ig production, cytokine release and many other processes, including atherosclerosis. Patients suffering from renal diseases present significant alterations of the costimulatory pathways, which might make them particularly liable to infections. These alterations are further pronounced in patients undergoing kidney transplantation. In these patients, different costimulatory patterns have been related to distinct clinical features. The importance that costimulation has gained during the last years has led to development of several pharmacological approaches to modulate this critical step in the immune activation. Different drugs, mainly monoclonal antibodies targeting various costimulatory molecules (i.e. anti-CD80, CTLA-4 fusion proteins, anti-CD154, anti-CD40, etc.) were designed and tested in both experimental and clinical studies. The results of these studies highlighted some criticisms, but also some promising findings and now costimulatory blockade is considered a suitable strategy, with belatacept (a CTLA-4 fusion protein) being approved as the first costimulatory blocker for use in renal transplantation. In this review, we summarize the current knowledge on costimulatory pathways in the setting of kidney transplantation. We describe the principal costimulatory molecule families, their role and clinical significance in patients undergoing renal transplantation and the new therapeutic approaches that have been developed to modulate the costimulatory pathways.

Invariant natural killer T cells are depleted in renal impairment and recover after kidney transplantation

BACKGROUND

Altered immune function in patients with renal failure results in both susceptibility to infection and increased inflammatory response. Invariant natural killer T (iNKT) cells are a conserved, immunoregulatory T lymphocyte subset that responds to lipid antigens with near-immediate cytokine production and cytotoxicity. iNKT cells are required for the antibacterial host response. Whether renal failure and renal replacement therapy alter iNKT cell abundance or phenotype has not been investigated.

METHODS

iNKT cells were studied by flow cytometry in the peripheral blood of patients with acute renal failure, chronic haemo- and peritoneal dialysis (PD), chronic kidney disease and after renal transplantation.

RESULTS

A very marked reduction in iNKT lymphocytes was found in acute renal failure before the first haemodialysis (HD) session. iNKT cells were depleted in end-stage renal disease patients receiving either HD or PD. iNKT cell depletion was accentuated after an HD session. Lesser degrees were observed in patients with non-dialysis-dependent chronic kidney disease. CD56 and CD161 NK cell marker expression was decreased in renal impairment. CD56(+) and CD161(+) iNKT cells produced more interferon-γ than negative cells of the same donor. Within the first year after kidney transplantation, the decrease in iNKT cells and their NK cell markers was reverted.

CONCLUSIONS

We describe for the first time that iNKT lymphocytes are reduced in end-stage renal disease and further depleted by HD. iNKT cells are important for early host response including activation of other immune cells and their depletion may contribute to immune dysfunction in renal disease.

Evidence for anti-inflammatory effects of exercise in CKD

CKD is associated with a complex state of immune dysfunction characterized by immune depression, predisposing patients to infections, and immune activation, resulting in inflammation that associates with higher risk of cardiovascular disease. Physical exercise may enhance immune function and exert anti-inflammatory effects, but such effects are unclear in CKD. We investigated the separate effects of acute and regular moderate-intensity aerobic exercise on neutrophil degranulation (elastase release), activation of T lymphocytes (CD69 expression) and monocytes (CD86 and HLA-DR expression), and plasma inflammatory markers (IL-6, IL-10, soluble TNF-receptors, and C-reactive protein) in patients with predialysis CKD. A single 30-minute (acute) bout of walking induced a normal pattern of leukocyte mobilization and had no effect on T-lymphocyte and monocyte activation but improved neutrophil responsiveness to a bacterial challenge in the postexercise period. Furthermore, acute exercise induced a systemic anti-inflammatory environment, evidenced by a marked increase in plasma IL-10 levels (peaked at 1 hour postexercise), that was most likely mediated by increased plasma IL-6 levels (peaked immediately postexercise). Six months of regular walking exercise (30 min/d for 5 times/wk) exerted anti-inflammatory effects (reduction in the ratio of plasma IL-6 to IL-10 levels) and a downregulation of T-lymphocyte and monocyte activation, but it had no effect on circulating immune cell numbers or neutrophil degranulation responses. Renal function, proteinuria, and BP were also unaffected. These findings provide compelling evidence that walking exercise is safe with regard to immune and inflammatory responses and has the potential to be an effective anti-inflammatory therapy in predialysis CKD.

Dialysis-requiring acute kidney injury increases risk of long-term malignancy: a population-based study

BACKGROUND

Acute kidney injury (AKI) is gaining worldwide attention recently, emerging as a major public health threat. However, the association between the development of AKI and subsequent malignancy has not been studied before.

METHODS

We conducted a population study based on the Taiwan National Health Insurance database, using 1,000,000 representative database during 2000-2008. All patients' survival to discharge from index hospitalization with recovery from dialysis-requiring AKI were identified (recovery group), and matched with those without recovery and those without AKI, at a 1:1:1 ratio.

RESULTS

We identified 625 individuals more than 18 years old [352 male (56.5%); mean age, 63.3 years] in recovery group and matched 625 individuals in each group. During a mean followed-up of 3.7 years, the incidences of new-onset malignancy were 4.2, 2.9, and 2.6 per 100 person-year among the non-recovery, the recovery, and the non-AKI group, respectively. After adjustment, the recovery group was more likely to develop long-term de novo malignancy than those without AKI [hazard ratio (HR) 1.44, 95% confidence interval (CI) 1.02-2.03; p = 0.04], while less likely than those who did not recover (HR 0.66, 95% CI 0.45-0.98; p = 0.04).

CONCLUSIONS

Dialysis-requiring AKI can post a long-term risk of de novo malignancy for those who survive from the initial insult. Even patients who have recovered from dialysis still carry a significantly higher possibility of developing malignancy than those without AKI episode.

Successful withdrawal of antiviral treatment in kidney transplant recipients with chronic hepatitis B viral infection

BACKGROUND

The optimal duration of antiviral therapy for kidney transplant recipients (KTR) with chronic hepatitis B virus (HBV) infection remains unclear. We reported the long-term outcomes after withdrawal of antiviral agent in KTR with chronic HBV infection.

METHODS

We retrospectively investigated the hepatitis B surface antigen (HBsAg)-positive KTR with antiviral agents between January 2002 and January 2012. Antiviral treatments were withdrawn in patients who met all of the following 7 criteria: (i) no clinical and histologic evidence of cirrhosis, (ii) normal liver biochemistry, (iii) negative for both HBV DNA and hepatitis B envelope antigen (HBeAg), (iv) no resistance to antiviral agent, (v) antiviral therapy > 9 months, (vi) maintenance dosage of immunosuppressant for > 3 months, and (vii) no history of acute rejection during recent 6 months. All patients were followed regularly at approximately 3-6 months for liver enzyme, viral markers, and HBV DNA level after antiviral withdrawal.

RESULTS

Among a total of 445 KTR, 14 HBsAg-positive patients were included in this study. Antiviral agents were used, with lamivudine in 11 patients, and with adefovir, entecavir, and telbivudine in 3 patients, respectively. Discontinuation of antiviral agent was attempted in 6 (42.9%) of 14 patients who satisfied the criteria. The median duration of antiviral therapy before withdrawal was 14.3 months (range, 9-24 months). Four (66.7%) of 6 patients were successfully withdrawn and remained negative for HBV DNA for a median 60.5 months (range, 47-82 months). The baseline HBV DNA level was not related to maintenance of remission after withdrawal. Two reactivated patients resumed antiviral treatment immediately, with subsequent normalization of HBV DNA. During the follow-up, 1 patient developed hepatocellular carcinoma; however, no patient death or graft failure was reported for all HBsAg-positive KTR.

CONCLUSIONS

Antiviral therapy can be discontinued successfully and safely in selected KTR with chronic HBV infection, after complete suppression of HBV and sufficient duration of antiviral therapy.

Genetic diversity of hepatitis C virus quasispecies in chronic renal failure patients in Midwest Brazil

Hepatitis C virus (HCV) quasispecies constitute a dynamic population in a continuous process of variation and selection. To investigate effect of the immune system on the genetic variability of HCV, we compared the hypervariable region 1 (HVR1) of immunosuppressed patients with chronic renal failure (CRF group) to immunocompetent patients with HCV chronic infection (control group). The HVR1 from ten samples of each group was amplified, cloned and sequenced. The HCV quasispecies from the control group had a higher frequency of variable sites in HVR1 (83.9 % vs 59.3 %, p < 0.05), as well as a greater diversity within (intra-patient) and between samples, compared to the CRF group. The clustering of the majority of the quasispecies of the CRF group in the phylogenetic tree also showed the limited diversity of the quasispecies in immunosuppressed patients. Moreover, a higher variability of amino acids at positions 384, 386, 391, 394, 397, 398, 400, 405 and 410 was observed in the control group than in the CRF group, which showed a greater variability only at position 388 (p < 0.05). These data corroborates the hypothesis that the major selective pressure factor is the immune system, which promotes a high degree of diversity in the viral progeny and contributes to a constant evolution of HCV.

Incidence of nosocomial hemodialysis-associated bloodstream infections at a county teaching hospital

BACKGROUND

Infections are an important cause of morbidity and mortality in patients undergoing hemodialysis. Limited information is to be found regarding nosocomial hemodialysis-associated bloodstream infections (HABSI).

METHODS

We sought to determine the rate of nosocomial HABSI and its associated risk factors at Riverside County Regional Medical Center. Inpatients who received hemodialysis during 2011 and 2012 were included, and outcomes were recorded along with risk factors. Data was analyzed with SPSS Inc software.

RESULTS

A total of 619 patients was included. Fourteen HABSI were detected, with a rate of 3.33/1,000 hemodialysis sessions and 1.03/1,000 patient-days. An association was detected between HABSI and vascular access type (highest risk with nontunneled catheters), length of hospital stay, number of hemodialysis sessions, and hemoglobin A1c level. A correlation was also noted between HABSI because of MRSA and colonization of nares with MRSA. A predominance of staphylococci infections was detected.

CONCLUSION

The rate of HABSI observed at Riverside County Regional Medical Center was lower than similar studies (2.5 per 1,000 patient-days and 3.95 per 1,000 hemodialysis sessions). The most important risk factors were determined to be nontunneled catheters, hemoglobin A1c greater than 7%, and nares colonization for HABSI because of MRSA. Infection prevention efforts in the inpatient hemodialysis population should focus on control of hyperglycemia and decolonization of nares from MRSA.

Vitamin D and the Immune System from the Nephrologist's Viewpoint

Vitamin D and its analogues are widely used as treatments by clinical nephrologists, especially when treating chronic kidney disease (CKD) patients with secondary hyperparathyroidism. As CKD progresses, the ability to compensate for elevations in parathyroid hormone (PTH) and fibroblast growth factor-23 and for decreases in 1,25(OH)₂D₃ becomes inadequate, which results in hyperphosphatemia, abnormal bone disorders, and extra-skeletal calcification. In addition to its calciotropic effect on the regulation of calcium, phosphate, and parathyroid hormone, vitamin D has many other noncalciotropic effects, including controlling cell differentiation/proliferation and having immunomodulatory effects. There are several immune dysregulations that can be noted when renal function declines. Physicians need to know well both the classical and nonclassical functions of vitamin D. This review is an analysis from the nephrologist's viewpoint and focuses on the relationship between the vitamin D and the immune system, together with vitamin's clinical use to treat kidney diseases.

Correlation of interleukin-17-producing effector memory T cells and CD4+CD25+Foxp3 regulatory T cells with the phosphate levels in chronic hemodialysis patients

Background and Objectives. Hyperparathyroidism and hyperphosphatemia contribute to the inflammatory effects in chronic hemodialysis (HD) patients. Interleukin-17-producing CD₄⁺ effector memory T (Th17) cells and CD4⁺CD25⁺Foxp3 regulatory T (Treg) cells both play critical roles in immune activation and inflammation. We investigated the relationship between the Treg and Th17 cells and the phosphate level in chronic HD patients. Methods. 105 patients aged ≥35 years on chronic HD over 3 months were enrolled. The peripheral blood mononuclear cells were collected, cultured, and stimulated by phytohemagglutinin-L, phorbol myristate acetate, and ionomycin at different time points for T cell differentiation. Results. The T cell differentiation was as follows: Th17 cells (mean ± standard deviation (SD): 25.61% ± 10.2%) and Treg cells (8.45% ± 4.3%). The Th17 cell differentiation was positively correlated with the phosphate and albumin levels and negatively correlated with age. The Treg cell differentiation was negatively correlated with albumin level and age. In the nondiabetes group (n = 53), the Th17 cell differentiation was predominantly correlated with the phosphate and iPTH (intact parathyroid hormone) levels as well as the dialysis vintage. Conclusion. Higher phosphate and iPTH levels and longer dialysis duration may increase Th17 cell differentiation, especially in the nondiabetic chronic HD patients.

MTHFR and HFE, but not preproghrelin and LBP, polymorphisms as risk factors for all-cause end-stage renal disease development

End-stage renal disease (ESRD) is a serious health problem worldwide. The high prevalence of cardiovascular diseases and chronic inflammation remains a major cause of morbidity and mortality in haemodialysed patients. Beside some external factors, genetic predisposition both to renal failure and poor prognosis has been assumed. We have collected a total of 1,014 haemodialysed patients and 2,559 unrelated healthy Caucasians. Single-nucleotide polymorphisms (SNPs) in genes for preproghrelin (GHRL), lipopolysaccharide-binding protein (LBP), HFE and MTHFR were genotyped. In the group of patients, significantly more carriers presented the MTHFR T667T (P = 0.002) and HFE Asp63Asp (P = 0.001) and Cys282Cys (P = 0.01) genotypes. The frequencies of individual SNPs within GHRL and LBP genes did not differ between the patients and controls. The trends in genotype frequencies did not differ between the subgroups of patients with different time on haemodialysis. Common variants in MTHFR and HFE could be a risk factor for all-cause ESRD development, but are not predictors for the survival on haemodialysis.

Impaired immune defense in hemodialysis patients: role of α-defensins?

The mechanisms underlying the impaired immune response in hemodialysis (HD) patients are not completely understood. The α-defensins human neutrophil peptides-1, 2, and 3 are low molecular weight peptides with antimicrobial activity and important effector molecules of innate immune responses. We now examined the expression of these peptides in HD patients. Seventy-six patients on chronic HD treatment (mean time on HD 5.8 years; mean age 70 years) were studied and compared with 38 healthy volunteers and 20 patients with infections and normal renal function. Expression of α-defensins was analyzed semiquantitatively in leukocytes on the messenger RNA (mRNA) level by reverse transcriptase polymerase chain reaction; the α-defensin protein levels in serum were detected by enzyme-linked immunosorbent assay. α-Defensin concentrations (140 ± 10.5 ng/mL; mean ± standard error of the mean) as well as mRNA levels in leukocytes (82.9 ± 7.9 arbitrary units [a.u.]) in HD patients were not significantly different from those in healthy volunteers (156 ± 15.2 ng/mL; 81.4 ± 11.3 a.u.). Defensin levels were independent of the time of the patient on HD and their age. During infection periods (mean increase of the C-reactive protein to 161 ± 17.3 mg/L), defensin serum levels increased to 321 ± 65 ng/mL (P < 0.005) and mRNA expression in leukocytes to 159 ± 19.2 a.u. (P < 0.05). These increases were not significantly different from those in patients with normal renal function (298 ± 46.8 ng/mL and 128 ± 9.1 a.u., respectively) suffering from infections (C-reactive protein 222 ± 26.6 mg/L). Our results suggest that the impaired immune defense in dialysis patients is not due to a deficiency in α-defensins in these patients as neither basal levels nor expression during infections were reduced compared with subjects with normal renal function.

Description and predictive factors of infection in patients with chronic kidney disease admitted to the critical care unit

OBJECTIVES

To describe the spectrum of infection and multidrug-resistant bacterial colonization, and to identify early predictors of infection in patients with chronic kidney disease (CKD) admitted to the critical care unit (CCU).

METHODS

A 7-month observational prospective single-centre study in a French university hospital.

RESULTS

791 patients were admitted to the CCU, 135 of whom (17%) had severe CKD. Among these, 41 (30%) were infected on admission. Infection was microbiologically documented in 32 patients (78%), of which 7 (22%) were related to Pseudomonas aeruginosa. There was no infection related to extended-spectrum β-lactamase-producing enterobacteriaceae despite a 12% carriage rate on admission. A temperature ≥37.6 °C and a leukocyte count >12.000/mm³ were specific but poorly sensitive of infection (91% and 80%, and 45% and 39%, respectively). Using the threshold of 0.85 ng/ml, procalcitonin was a strong independent predictor of infection on admission (OR 12.8, 95% CI 4.4-37.3). Age (≥60 years) and the cause of CKD were two other predictors.

CONCLUSIONS

Infection accounts for one-third of CCU admissions in CKD patients, with a high prevalence of P. aeruginosa. The usual diagnostic criteria are inaccurate for diagnosing infection in this population. A procalcitonin ≥0.85 ng/ml might be helpful for early identifying CKD patients with infection.

Influence of renal replacement therapy on immune response after one and two doses of the A(H1N1) pdm09 vaccine

BACKGROUND

Patients with end-stage renal disease have a reduced response to vaccination because of the general suppression of the immune system associated with uraemia.

OBJECTIVES

We evaluated the immune response and differential factors in the immunogenicity to an adjuvanted A(H1N1) pdm09 vaccine (Pandemrix(®) ) in four populations of renal patients after one and two doses of vaccine. PATIENTS METHODS: 151 patients were included in this study: 58 chronic haemodialysis patients, 52 renal allograft recipients, 14 peritoneal dialysis patients and 27 patients with advanced chronic kidney disease in preparation for kidney replacement therapy. Influenza-specific antibody levels were measured by monitoring A(H1N1) pdm09 titres using a haemagglutination inhibition assay.

RESULTS

The seroconversion rate at 42 days after two vaccine doses was 80% in the haemodialysis group, 64.9% in the renal allograft recipients group, 100% in the advanced chronic kidney disease group and 71.4% in the peritoneal dialysis group (P = 0.041).

CONCLUSIONS

Immune response to two doses of the influenza A H1N1 vaccine is dissimilar in the four renal conditions, confirming that seroprotection in pre-dialysis, haemodialysis and peritoneal dialysis is similar to that in the general population vaccinated with one dose. In contrast, renal transplant recipients with good allograft function showed inadequate protection and triple immunosuppressive therapy including calcineurin inhibitors, mycophenolate and steroids negatively influenced seroconversion after vaccination in renal recipients.

Acute myeloid leukemia in a 38-year-old hemodialyzed patient with von Hippel-Lindau disease

Von Hippel-Lindau disease (VHL disease) is a hereditary cancer predisposition syndrome caused by mutations of the von Hippel-Lindau tumor suppressor gene. The gene product, pVHL, regulates the level of proteins that play a central role in protecting cells against hypoxia. Clinical hallmarks of von Hippel-Lindau disease are the development of central nervous system hemangioblastomas, renal cell carcinoma, pheochromocytoma, neuroendocrine tumors and endolymphatic sac tumors.

In this article the case of a 38-year old hemodialyzed patient who became ill with acute myeloid leukemia (AML) three years after being diagnosed with von Hippel-Lindau disease is presented.

After cytostatic treatment the patient went into complete hematologic remission but there was still residual disease at the genetic level. After consolidation therapy patient developed bone marrow aplasia and severe pneumonia. Despite intensive treatment the patient died from acute respiratory failure.

In this paper we present for the first time a case of von Hippel-Lindau disease associated with acute myeloid leukemia. No evidence of relationship between VHL disease and blood cancers has been demonstrated so far. Despite the fact that there is an increased risk of cancer development in hemodialyzed patients, cancer is a relatively rare cause of death in the dialysed population, and the most common malignancies are genitourinary cancers. It seems likely that development of acute myeloid leukemia in patient with VHL disease can be related to epigenetic alterations of the VHL gene, but further studies are needed.

Increased visfatin in hemodialysis patients is associated with decreased demands for recombinant human erythropoietin

BACKGROUND

Studies detected an association between visfatin and markers of iron metabolism in patients with insulin resistance. In this study, such a relation was evaluated in hemodialysis (HD) patients. Also relations between visfatin and hepcidin, demands for recombinant human erythropoietin (rHuEpo), inflammation, and situations characterized by insulin resistance were evaluated.

METHODS

After a four-week washout period from iron treatment, 33 HD patients and 20 healthy volunteers enrolled in the study. Serum visfatin, hepcidin, and interleukin-6 (IL-6) were assessed by means of enzyme-linked immunosorbent assay. Hemoglobin, serum iron, ferritin, and transferrin saturation (TSAT) were also measured.

RESULTS

Visfatin was markedly increased in HD patients. Visfatin levels did not differ between diabetics and non-diabetics. No relation was detected between visfatin and body mass index or IL-6 in HD patients. From the markers of iron metabolism, the hepcidin included, visfatin was related only to TSAT. A strong positive relation was revealed between visfatin and hemoglobin, whereas visfatin was inversely related to rHuEpo dose. Resistance to rHuEpo index was inversely and independently of TSAT related to visfatin.

CONCLUSION

Visfatin is increased in HD patients and it is associated with decreased demands for rHuEpo.

Ferroportin in monocytes of hemodialysis patients and its associations with hepcidin, inflammation, markers of iron status and resistance to erythropoietin

PURPOSE

Disturbed iron homeostasis contributes to resistance to recombinant human erythropoietin (rHuEpo) in hemodialysis (HD) patients. Increased hepcidin, which downregulates the iron exporter ferroportin, has been incriminated. However, other factors also control ferroportin expression in mononuclear phagocyte system. Ferroportin in monocytes, as well as serum hepcidin, interleukin-6 (IL-6) and common markers of iron status were measured and correlations with rHuEpo resistance index (ERI) were evaluated.

METHODS

After a 4-week washout period from iron treatment, 34 HD patients and 20 healthy volunteers enrolled in the study. Ferroportin was assessed by means of western blotting, whereas hepcidin and IL-6 with enzyme-linked immunosorbent assay. Hemoglobin, serum iron, ferritin and transferrin saturation (TSAT) were also measured.

RESULTS

Ferroportin in monocytes of HD patients was decreased. Serum hepcidin and IL-6 were increased, whereas serum iron and TSAT were decreased. ERI was negatively correlated with ferroportin and all the markers of iron adequacy, but not with hepcidin.

CONCLUSION

Decreased ferroportin in monocytes of HD patients accompanies increased hepcidin, inflammation, decreased iron availability and is correlated with resistance to rHuEpo treatment.

Altered molecular repertoire of immune system by renal dysfunction in the elderly: is prediction and targeted prevention in the horizon?

Background

Patients on chronic hemodialysis (HD) have impaired cellular and humoral immunity. The percentage of elderly people among the total population in Taiwan is increasing dramatically, and HD is the primary alternative for renal replacement therapy when renal function declines. Activated vitamin D is widely used in HD patients with secondary hyperparathyroidism (SHPT) and is a well-known immunomodulatory agent. Personalized medicine and integrative medical approach has been a trend in current clinical practice. Can we improve their immune function using vitamin D in spite of the mineral aspect? Here, we investigated the relationship between serum 25-hydroxyvitamin D (25(OH)D) level and T cell differentiation in chronic HD patients.

Methods

Forty patients with chronic HD were enrolled. HD patients with SHPT had been treated with activated vitamin D for 3 months. Peripheral blood mononuclear cells obtained from the patients were cultured and stimulated by mitogens, and T cells were analyzed by flow cytometry. Serum 25(OH)D levels were detected by enzyme-linked immunosorbent assay.

Results

The incidence of T cell differentiation to the T helper cell (Th)2 subtype was more prevalent in the elderly group than in the controls (p = 0.001). Th2 differentiation was also correlated with age (p = 0.004) and serum 25(OH)D levels (p < 0.05). After treated with activated vitamin D, the level of Th1 cytokines decreased while the Th2 cytokine level increased in the sera (p < 0.05). The T cell differentiation tended toward the Th2 subtype (p = 0.027) after treatment of activated vitamin D in SHPT patients.

Conclusions

These results demonstrated that Th2 differentiation is correlated with age and the serum 25(OH)D level of patients. Treatment with activated vitamin D influenced T cell differentiation and cytokine expression in SHPT patients. Taking vitamin D is the possible prediction and targeted treatment in the immune dysfunction in chronic HD patients.

A specific immune transcriptomic profile discriminates chronic kidney disease patients in predialysis from hemodialyzed patients

BACKGROUND

Chronic kidney disease (CKD) patients present a complex interaction between the innate and adaptive immune systems, in which immune activation (hypercytokinemia and acute-phase response) and immune suppression (impairment of response to infections and poor development of adaptive immunity) coexist. In this setting, circulating uremic toxins and microinflammation play a critical role. This condition, already present in the last stages of renal damage, seems to be enhanced by the contact of blood with bioincompatible extracorporeal hemodialysis (HD) devices. However, although largely described, the cellular machinery associated to the CKD- and HD-related immune-dysfunction is still poorly defined. Understanding the mechanisms behind this important complication may generate a perspective for improving patients outcome.

METHODS

To better recognize the biological bases of the CKD-related immune dysfunction and to identify differences between CKD patients in conservative (CKD) from those in HD treatment, we used an high-throughput strategy (microarray) combined with classical bio-molecular approaches.

RESULTS

Immune transcriptomic screening of peripheral blood mononuclear cells (1030 gene probe sets selected by Gene-Ontology) showed that 275 gene probe sets (corresponding to 213 genes) discriminated 9 CKD patients stage III-IV (mean±SD of eGFR: 32.27+/-14.7 ml/min) from 17 HD patients (p<0.0001, FDR=5%). Seventy-one genes were up- and 142 down-regulated in HD patients. Functional analysis revealed, then, close biological links among the selected genes with a pivotal role of PTX3, IL-15 (up-regulated in HD) and HLA-G (down-regulated in HD). ELISA, performed on an independent testing-group [11 CKD stage III-IV (mean±SD of eGFR: 30.26±14.89 ml/min) and 13 HD] confirmed that HLA-G, a protein with inhibition effects on several immunological cell lines including natural killers (NK), was down-expressed in HD (p=0.04). Additionally, in the testing-group, protein levels of CX3CR1, an highly selective chemokine receptor and surface marker for cytotoxic effector lymphocytes, resulted higher expressed in HD compared to CKD (p<0.01).

CONCLUSION

Taken together our results show, for the first time, that HD patients present a different immune-pattern compared to the un-dialyzed CKD patients. Among the selected genes, some of them encode for important biological elements involved in proliferation/activation of cytotoxic effector lymphocytes and in the immune-inflammatory cellular machinery. Additionally, this study reveals new potential diagnostic bio-markers and therapeutic targets.

Comparison of regulatory T cells in hemodialysis patients and healthy controls: implications for cell therapy in transplantation

BACKGROUND AND OBJECTIVES

Cell-based therapy with natural (CD4(+)CD25(hi)CD127(lo)) regulatory T cells to induce transplant tolerance is now technically feasible. However, regulatory T cells from hemodialysis patients awaiting transplantation may be functionally/numerically defective. Human regulatory T cells are also heterogeneous, and some are able to convert to proinflammatory Th17 cells. This study addresses the suitability of regulatory T cells from hemodialysis patients for cell-based therapy in preparation for the first clinical trials in renal transplant recipients (the ONE Study).

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Healthy controls and age- and sex-matched hemodialysis patients without recent illness/autoimmune disease on established, complication-free hemodialysis for a minimum of 6 months were recruited. Circulating regulatory T cells were studied by flow cytometry to compare the regulatory T cell subpopulations. Regulatory T cells from members of each group were compared for suppressive function and plasticity (IL-17-producing capacity) before and after in vitro expansion with and without Rapamycin, using standard assays.

RESULTS

Both groups had similar total regulatory T cells and subpopulations I and III. In each subpopulation, regulatory T cells expressed similar levels of the function-associated markers CD27, CD39, HLA-DR, and FOXP3. Hemodialysis regulatory T cells were less suppressive, expanded poorly compared with healthy control regulatory T cells, and produced IL-17 in the absence of Rapamycin. However, Rapamycin efficiently expanded hemodialysis regulatory T cells to a functional and stable cell product.

CONCLUSIONS

Rapamycin-based expansion protocols should enable clinical trials of cell-based immunotherapy for the induction of tolerance to renal allografts using hemodialysis regulatory T cells.

The relationship between red cell distribution width with erythropoietin resistance in iron replete hemodialysis patients

BACKGROUND

Recently, erythropoietin resistance (ER) has been shown to be related with cardiovascular and overall mortality in hemodialysis (HD) patients. Red blood cell distribution width (RDW) has also shown to be associated with cardiovascular and all cause mortality in general population. Thus in the current study we tested the hypothesis that RDW and erythropoietin resistance as determined by erythropoiesis stimulating agents (ESA) hyporesponsiveness index (EHRI) may be related with each other in iron replete HD patients.

METHODS

Study participants underwent medical history taking, physical examination, calculation of dialysis adequacy and biochemical analysis. EHRI was calculated as the weekly dose of EPO divided by per kilogram of body weight divided by the hemoglobin level.

RESULTS

Two separate analyses were performed. In the first analysis performed in 94 HD patients; the stepwise linear regression analysis revealed that being female (P=0.031), HD duration (P=0.021), presence of diabetes mellitus (P=0.008), RDW (P=0.023), and predialysis sodium (P=0.05) were independently related with logarithmically converted EHRI. We made second analysis after 4 months. The second analysis revealed that when compared to first EHRI, the EHRI was increased in 40, unchanged in one and decreased in 40 patients The second stepwise regression analysis also showed that the independent relationship with RDW and EHRI was persisted (β=0.050, CI: 0.022-0.078, P=0.001).

CONCLUSION

Red blood cell distribution width was independently related with EHRI in iron replete HD patients.

Damage-associated molecular patterns derived from mitochondria may contribute to the hemodialysis-associated inflammation

PURPOSE

Inflammation is common in hemodialysis (HD) patients. Mitochondrial damage-associated molecular patterns (DAMPs) are released during cell necrosis or apoptosis and induce inflammation. Cell apoptosis is increased in HD patients. The mitochondrial protein cytochrome c, as a marker of released mitochondrial DAMPs, and interleukin-6 (IL-6), as a marker of inflammation, were evaluated in HD patients.

METHODS

Thirty-four HD patients and 20 controls were enrolled in the study. Serum cytochrome c and IL-6 were measured by means of enzyme-linked immunosorbent assay.

RESULTS

Compared to controls, cytochrome c was markedly increased in HD patients (1392.88 ± 905.24 pg/mL vs. 212.95 ± 91.71 pg/mL). IL-6 was also significantly increased in HD patients (50.32 ± 35.89 pg/mL vs. 14.27 ± 6.83 pg/mL). In HD patients serum IL-6 was positively related to serum cytochrome c (r = 0.458).

CONCLUSION

Both circulating cytochrome c and IL-6 are markedly increased in HD patients. Cytochrome c is positively related to IL-6.

Plasma vascular endothelial growth factor and angiogenin are positively related to erythropoietin dose in hemodialysis patients

PURPOSE

Experimental data confirmed that erythropoietin (EPO) administration alters the course of various pathological situations such as heart failure and tumor growth by inducing vascular endothelial growth factor-A (VEGF-A) expression. The effect of EPO dose on plasma VEGF-A level in hemodialysis (HD) patients was evaluated. The effect of EPO dose on plasma angiogenin level in HD patients was also evaluated, since angiogenin is necessary for angiogenesis induced by VEGF-A.

METHODS

Thirty two HD patients (10 diabetics) enrolled into the study. Patients were iron replete and did not suffer from infections, autoimmune diseases or malignancies. Plasma VEGF-A and angiogenin, as well as serum interleukin-6 and tumor necrosis factor-α were measured by means of ELISA.

RESULTS

Weekly EPO dose per kg of dry body weight was positively related to both VEGF-A and angiogenin, whereas no relation was detected among VEGF-A or angiogenin and hemoglobin, inflammation or presence of diabetes mellitus. These relations among EPO dose and VEGF-A or angiogenin remained after adjustment for hemoglobin concentration or inflammation or presence of diabetes mellitus.

CONCLUSIONS

EPO dose may affect plasma VEGF-A and angiogenin concentrations in HD patients.

Antibody response after single H1N1 influenza vaccine in chronic dialysis patients

The first influenza pandemic of this century happened through a rapid spread of a novel swine-derived H1N1 influenza virus. Vaccines are produced in order to avoid the infection. Children and other high risk groups are highly recommended for vaccination due to the high probability of contracting the virus. Chronic kidney disease patients were also accepted as a risk group and vaccination of all patients undergoing hemodialysis or peritoneal dialysis was recommended. The results of H1N1 influenza virus vaccine on patients receiving hemodialysis and peritoneal dialysis are analyzed. Antibody titers of both hemodialysis and peritoneal dialysis patients were elevated after vaccination. Peritoneal dialysis patients responded better.

Association of response to hepatitis B vaccination and survival in dialysis patients

Background

The status of immunocompromised patients is well recognized in end stage renal disease (ESRD). As described recently, this acquired immune dysfunction in the uremic milieu may be one of the main pathogenic factors for mortality in ESRD. The aim of this study was to determine the relationship between the immune response following a hepatitis B vaccination (HBV vaccination) and the survival of maintenance dialysis patients.

Methods

A total of 156 patients (103 on hemodialysis and 53 on continuous ambulatory peritoneal dialysis) were recruited. After receiving a full dose of the HBV vaccination, all patients were followed up for to 5 years to evaluate the association of patient survival, cause of mortality, and immune response.

Results

The response rate to the hepatitis B vaccination was 70.5%. There was no significant association between the immune response and the 5-year survival rate (p =0.600) or between the post-vaccination anti-HBs titers and the 5-year survival rate (p = 0.201). The logistic prediction model with the coefficient as non-response following HBV vaccination, diabetes mellitus, old age, and low albumin level could significantly predict infection-cause mortality (sensitivity = 0.842, specificity = 0.937).

Conclusion

There was no significant association between the immune response to HBV vaccination and the 5-year survival rate. However, non-response following HBV vaccination might be associated with infection-cause mortality in dialysis patients.

Plasma indoleamine 2,3-dioxygenase and arginase type I may contribute to decreased blood T-cell count in hemodialysis patients

BACKGROUND

Acquired immunity is impaired in hemodialysis (HD) patients, and decreased T-cell number may contribute. Indoleamine 2,3-dioxygenase (IDO) and arginase type I (ARG) catabolize tryptophane and arginine, respectively, and exert proapoptotic and antiproliferative effects on T-cells. Plasma levels of IDO and ARG and their relation to blood T-cell number were evaluated in HD patients.

METHODS

Thirty-two HD patients and 20 healthy controls participated in the study. Plasma IDO and ARG were measured by means of enzyme-linked immunosorbent assay. T-cell number was assessed by means of flow cytometry.

RESULTS

IDO concentration was significantly higher in HD patients than in healthy volunteers (44.30 ± 31.83 ng/mL vs. 21.28 ± 26.21 ng/mL, p = 0.009). There was a trend for higher ARG concentration in HD patients (13.43 ± 11.91 ng/mL) than in healthy volunteers (9.56 ± 4.03 ng/mL), which, however, did not reach statistic significance (p = 0.099). Absolute T-cell count was significantly lower in HD patients than in healthy controls (1176.99 ± 567.71 cells/mm3 vs. 1519.85 ± 594.96 cells/mm3, p = 0.040). Absolute blood T-cell number was inversely related to plasma IDO (r = -0.490, p = 0.004) and to plasma ARG (r = -0.387, p = 0.029) concentrations.

CONCLUSIONS

Plasma IDO and ARG may contribute to decreased blood T-cell count in HD patients.

Perilipin-1 in hemodialyzed patients: association with history of coronary heart disease and lipid profile

Perilipin-1 surrounds lipid droplets in both adipocytes and in atheroma plaque foam cells and controls access of lipases to the lipid core. In hemodialysis (HD) patients, dyslipidemia, malnutrition, inflammation and atherosclerosis are common. Thirty-six HD patients and 28 healthy volunteers were enrolled into the study. Ten HD patients suffered from coronary heart disease (CHD). Perilipin-1, triglycerides, total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol (HDL-C), body mass index, albumin, geriatric nutritional risk index, normalized protein catabolic rate, interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) were measured. Perilipin-1 did not differ between HD patients and healthy volunteers. IL-6 and TNF-α were higher in HD patients. The evaluated nutritional markers and the markers of inflammation did not differ between HD patients with high perilipin-1 levels and HD patients with low perilipin-1 levels. Regarding the lipid profile, only HDL-C differed between HD patients with high perilipin-1 levels and HD patients with low perilipin-1 levels, and it was higher in the first subgroup. Perilipin-1 was significantly higher in HD patients without CHD. Perilipin-1 is detectable in the serum of HD patients and it is associated with increased HDL-C and decreased incidence of CHD.

Mechanisms underlying sCD40 production in hemodialysis patients

CD40 and its ligand (CD40L) regulate several cellular functions, including T and B-cell activation. The soluble form of CD40 (sCD40) antagonizes CD40/CD40L interaction. Patients undergoing hemodialysis (HD) present elevated sCD40 serum levels, which underlying molecular mechanisms are unknown. We studied sCD40 serum and urinary levels, CD40 membrane and gene expression and membrane shedding in HD, uremic not-HD patients (UR) and healthy subjects (N). We found that in HD sCD40 serum levels were higher than UR and N, being significantly elevated in anuric patients, and that sCD40 correlated to renal function in UR subjects, who presented also a reduced sCD40 urinary excretion rate. HD and UR presented reduced CD40 membrane and gene expression. The concentration of TNF-α converting enzyme (TACE), responsible for CD40 cleavage was not different between HD and N. Therefore the reduced renal clearance is the main cause of elevated sCD40 levels in HD. This finding could have relevant clinical implications.