Early T cell activation correlates with expression of apoptosis markers in patients with end-stage renal disease

The inactivated herpes zoster vaccine HZ/su induces a varicella zoster virus specific cellular and humoral immune response in patients on dialysis

BACKGROUND

To evaluate the immunogenicity of the inactivated herpes-zoster vaccine HZ/su in patients at increased risk for VZV-reactivation, we analysed the quantity and quality of the vaccine-induced cellular and humoral immunity in patients on dialysis with uremic immunodeficiency.

METHODS

In this observational study, 29 patients and 39 immunocompetent controls underwent standard dual-dose vaccination. Blood samples were analysed before and two weeks after each vaccination, and after one year. Specific T-cells were characterized after stimulation with VZV-gE-peptides based on induction of cytokines and CTLA-4-expression using flow-cytometry. Antibodies were analysed using ELISA.

FINDINGS

Both groups showed an increase in VZV-gE-specific CD4 T-cell levels over time (p < 0.0001), although median levels reached after second vaccination were lower in patients (0.17% (IQR 0.21%)) than in controls (0.24% (IQR 0.3%), p = 0.042). VZV-gE specific CD8 T-cells were only poorly induced. CTLA-4 expression on VZV-gE-specific CD4 T-cells was strongest after second dose with no differences between the groups (p = 0.45). Multifunctional cells co-expressing IFNγ, IL-2, and TNF were higher in patients after first vaccination (p = 0.028). Median VZV-specific IgG-levels reached a maximum after second vaccination with significantly lower levels in patients (10796 (IQR 12482) IU/l) than in controls (16899 (IQR 14019) IU/l, p = 0.009). Despite similar CD4 T-cell levels after one year (p = 0.415), antibody levels remained significantly lower in patients (p = 0.0008).

INTERPRETATION

VZV-gE vaccination induced specific antibodies and CD4 T-cells in both patients and controls, whereas CD8 T-cell-induction was poor. Quantitative and qualitative differences in immunity may indicate reduced duration of protection which may necessitate booster vaccinations in patients on dialysis.

FUNDING

HOMFORexzellent (to D.S.).

Cutaneous adaptive immunity and uraemia: a narrative review

Chronic kidney disease affects 1 in 10 people globally, with a prevalence twenty times that of cancer. A subset of individuals will progress to end-stage renal disease (ESRD) where renal replacement therapy is required to maintain health. Cutaneous disease, including xerosis and pruritus, are endemic amongst patients with ESRD. In the uraemia-associated immune deficiency of ESRD, impaired circulating immune responses contribute to increased infection risk and poorer vaccination response. Clinical manifestations of dysregulated adaptive immunity within the skin have been well-described and have been posited to play a role in cutaneous features of ESRD. However, our understanding of the mechanisms by which adaptive immunity within the skin is affected by uraemia is relatively limited. We provide an overview of how the cutaneous adaptive immune system is impacted both directly and indirectly by uraemia, highlighting that much work has been extrapolated from the circulating immune system and often has not been directly evaluated in the skin compartment. We identify knowledge gaps which may be addressed by future research. Ultimately, greater understanding of these pathways may facilitate novel therapeutic approaches to ameliorate widespread cutaneous symptomatology in ESRD.

PMMA dialyzers modulate both humoral and cell-mediate immune response to anti-COVID-19 vaccine (BNT162b2) in a cohort of chronic hemodialyzed patients

Patients on hemodialysis (HD) have a high risk of death from COVID-19. We evaluated the humoral and cell-mediated immune response to BNT162b2 (Pfizer-BioNTech) vaccine in HD patients, comparing HD with Poly-methyl-methacrylate (PMMA) and HD with Polysulphone (PS). Samples were collected before vaccination (T0) and 14-days after the 2ndvaccine (T2) in a TG (TG, n = 16-Foggia) and in a VG (CG, n = 36-Novara). Anti-SARS-CoV-2-Ig were titrated in the cohort 2-weeks after the 2nddose of vaccine. In the Testing-Group, serum neutralizing antibodies (NAb) were assayed and PBMCs isolated from patients were thawed, counted and stimulated with SARS-CoV-2 IGRA stimulation tube set. All patients had a positive ab-response, except in a case. PMMA-patients had higher levels of anti-SARS-CoV-2 IgG (p = 0.031); VG data confirmed these findings (p < 0.05). NAb evaluation: PMMA patients passed the positive cut-off value, while in PS group only only 1/8 patient did not respond. PMMA patients showed higher percentages of anti-SARS-CoV-2 S1/RBD-Ig after a complete vaccine schedule (p = 0.028). Interferon-gamma release: PMMA patients showed significantly higher release of IFNγ (p = 0.014). The full vaccination course provided sufficient protection against SARS-CoV-2 across the entire cohort, regardless of dialyzer type. After vaccination, PMMA patients show a better immune response, both humoral and cellular, at the end of the vaccination course than PS patients.

CD73 as a T cell dysfunction marker predicting cardiovascular and infection events in patients undergoing hemodialysis

BACKGROUND

T cell dysfunction observed in patients undergoing hemodialysis (HD) has been linked to an extremely high morbidity of cardiovascular events (CVEs) and infections. The cell-surface 5'-nucleotidase CD73 sets the balance between pro-inflammatory nucleotides and anti-inflammatory adenosine.

METHODS

A total of 395 patients who had been receiving HD for at least six months were evaluated for proportions of CD73+ cells in both the CD4+ T cell and CD8+ T cell compartment and followed for one year to document CVEs and infections. Differences in the proportions of CD73-expressingT cells between healthy controls and patients undergoing HD were compared. The relationship between CD73+ T cells and clinical outcomes was analyzed using the Kaplan-Meier curve and Cox regression.

RESULTS

HD was significantly related to a lower fraction of CD4+CD73+ T cells. In patients on HD, lower proportions of CD4+ CD73+T cells and CD8+ CD73+T cells were both associated with systemic inflammation and T cell terminal differentiation. More importantly, a lower CD4+CD73+T cell ratio independently predicted CVEs and infection in these patients.

CONCLUSION

We identified CD73 as a T cell dysfunction marker predicting cardiovascular and infection events in patients undergoing HD, which provides a potential target in future studies of uremia-related immune dysfunction.

Determinants of vaccine adherence among non-dialysis chronic kidney disease patients in Qatar

INTRODUCTION

Chronic kidney disease (CKD) is a global health problem. Reduced innate and adaptive immunological responses predispose CKD patients to infections. Despite the clinical and epidemiological importance of CKD and the great value of vaccination as a prophylactic measure, the utilization of recommended vaccines in Qatar has not yet been evaluated.

METHODS

We conducted a cross-sectional study to estimate the level of influenza, pneumococcal, and hepatitis B vaccination and the predictors of adherence to these recommended vaccines among non-dialysis CKD patients receiving renal ambulatory care in Qatar from 1 September 2020 to 30 April 2021. Complete vaccination was defined as receiving the three vaccines, and partial vaccination was defined as receiving one or two vaccines. The full and partial vaccination predictors were assessed using multivariate logistic regression and reported as odds ratio (OR) with p<0.05 indicating statistical significance.

RESULTS

416 non-dialysis CKD patients were included in our analysis. 73% were males; the mean age was 56 ± 15 years. More than 50% of the patients were from the Middle East, followed by 36% from Asia. Most patients had concurrent hypertension, concurrent diabetes mellitus, and were stage V CKD. Only 12% of the patients were fully vaccinated, while 73% received partial vaccination. The predictors of vaccination included age, gender, Asian origin, employment, living conditions, concurrent medical conditions, CKD stage, allergy to medications, and use of injectable medications. Only stage V CKD positively predicted adherence to full and partial vaccinations in non-dialysis CKD patients.

CONCLUSION

There is very low adherence to the recommended vaccines in CKD patients, with a prevalence of complete vaccination of 12% only. Increased public awareness about the importance of vaccination in CKD may improve the adherence rates among these patients in Qatar.

Immunological features of ESRD patients undergoing hemodialysis of various ages

AIMS

To investigate the immunological characteristics of hemodialysis (HD) patients with end-stage renal disease (ESRD) of various ages, and the impact of age-related immune alterations on these patients, with a focus on peripheral T cells.

METHODS

From September 2016 to September 2019, HD patients were enrolled and followed prospectively for 3 years. Patients were divided into three groups based on their ages: < 45, 45 to 64, and ≥ 65. The distribution of T cell subsets in different age groups was investigated and compared. The effects of altered T cell subsets on overall survival were also investigated.

RESULTS

A total of 371 HD patients were enrolled. The reduced number of naive CD8+ T cells (P < 0.001) and increased number of EMRA CD8+ T cells (P = 0.024) were independently associated with the advanced age among all T cell subsets studied. Patient survival may be affected by numerical changes in naive CD8+ T cells. However, when HD patients were < 45 or ≥ 65 years, the reduction had no significant impact on survival. Only in HD patients aged 45 to 64 years, the number of naïve CD8+ T cells found to be insufficient but not deficient, identified as an independent predictor of poor survival.

CONCLUSIONS

The most significant age-related immune change in HD patients was a decrease in peripheral naive CD8+ T cells, which was an independent predictor of 3-year overall survival in HD patients aged 45 ~ 64 years.

Immunophenotypic Characterization of Citrate-Containing A Concentrates in Maintenance Hemodialysis: A Pre-Post Study

Introduction

Due to chronic inflammation, maintenance hemodialysis (MHD) patients continue to show excess mortality. Acetate-free citrate-buffered A concentrates could be a way to improve the biocompatibility of the procedure, reduce chronic inflammation, and thus in the long term improve the prognosis of patients.

Methods

Using a pre-post design (3 months of acetate followed by 3 months of citrate-acidified A concentrates in standard bicarbonate-based dialysate hemodialysis, CiaHD) and linear mixed model analysis in 61 stable HD patients, we assessed the impact of CiaHD on counts and phenotypes of peripheral T cells and monocytes by flow cytometry.

Results

Switching to CiaHD left C-reactive protein (CRP) levels and leucocyte counts unaffected. However, CiaHD increased lymphocyte counts ex vivo. Furthermore, we found a decrease in total CD3+CD4+CD69+ ((109/L), mean ± SD: acetate, 0.04 ± 1.0 versus citrate, 0.02 ± 0.01; P = 0.02) activated cells, while the number of CD28+ T cells remained stable. No differences were noted regarding T-cell exhaustion marker expression, CD14+CD16+ monocyte counts, and PMN-MDSCs.

Conclusion

Compared with acetate, CiaHD has a minor impact on lymphocyte counts and CD4+T-cell activation, which was independent of systemic CRP and ionized magnesium, calcium levels, and other dialysis prescription modalities.

Roles of extracellular vesicles in ageing-related chronic kidney disease: demon or angel

Ageing is a universal and unavoidable phenomenon that significantly increases the risk of developing chronic kidney disease (CKD). It has been reported that ageing is associated with functional disruption and structural damage to the kidneys. Extracellular vesicles (EVs), which are nanoscale membranous vesicles containing lipids, proteins, and nucleic acids, are secreted by cells into the extracellular spaces. They have diverse functions such as repairing and regenerating different forms of ageing-related CKD and playing a crucial role in intercellular communication. This paper reviews the etiology of ageing in CKD, with particular attention paid to the roles of EVs as carriers of ageing signals and anti-ageing therapeutic strategies in CKD. In this regard, the double-edged role of EVs in ageing-related CKD is examined, along with the potential for their application in clinical settings.

Enhancing Immune Protection in Hemodialysis Patients: Role of the Polymethyl Methacrylate Membrane

End-stage renal disease (ESRD) is characterized by deep disorders in both innate and adaptive immune systems that imply unbalance deactivation and immunosuppression. The central, widely recognized factors responsible for this immune dysregulation are uremia, uremic toxin retention, hemodialysis membrane biocompatibility, and related cardiovascular complications. Recently, several studies strengthened the concept that dialysis membranes are not considered as a simple diffusive/adsorptive device but as a platform to personalize a dialysis approach to improve the quality of life of ESRD patients. Therefore, understanding of the molecules associated with altered immune response is crucial and could lead to therapeutically intervention or adaptation of the dialysis procedure itself for the management of immunological dysfunction of ESRD patients. The polymethyl methacrylate (PMMA)-based membrane is characterized by a symmetrical structure with large-sized pores, providing a better hydrophobic and cationic adsorption capacity compared to the other synthetic membranes. Together with hydrophobic interactions, the high adsorption rate of cytokines (i.e., IL-6) can also be enhanced by the size of nano-pores placed on the membrane surface. PMMA membranes exhibit adsorptive properties for a large amount of uremic toxins including p-cresol and indoxyl sulfate, as well as β2-microglobulin characterized by higher molecular weight, maintaining the diffusive clearance of small molecules like urea with a great biocompatibility. Besides exerting a strong anti-inflammatory effects in line with the improvement of immune responses in patients undergoing dialysis, PMMA also plays a role in modulating adaptive immune response, i.e., can clear blood from soluble CD40, a natural antagonist of the CD40/CD40L signaling that acts inhibiting immunoglobulin production by B cells. This review provides an overview of the main concepts and current understanding of immune dysfunction in hemodialysis and summarizes the recent findings regarding PMMA-based dialysis as potential strategy to restore immune balance in ESRD patients.

Hemodialysis-Associated Immune Dysregulation in SARS-CoV-2-Infected End-Stage Renal Disease Patients

Patients on hemodialysis show dysregulated immunity, basal hyperinflammation and a marked vulnerability to COVID-19. We evaluated the immune profile in COVID-19 hemodialysis patients and the changes associated with clinical deterioration after the hemodialysis session. Recruited patients included eight hemodialysis subjects with active, PCR-confirmed SARS-CoV-2 infection, five uninfected hemodialysis patients and five healthy controls. In SARS-CoV-2-infected hemodialysis patients TNF-α, IL-6 and IL-8 were particularly increased. Lymphopenia was mostly due to reduction in CD4+ T, B and central memory CD8+ T cells. There was a predominance of classical and intermediate monocytes with reduced HLA-DR expression and enhanced production of pro-inflammatory molecules. Immune parameters were analysed pre- and post-hemodialysis in three patients with COVID-19 symptoms worsening after the hemodialysis session. There was a higher than 2.5-fold increase in GM-CSF, IFN-γ, IL-1β, IL-2, IL-6, IL-17A and IL-21 in serum, and augmentation of monocytes-derived TNF-α, IL-1β and IL-8 and CXCL10 (p < 0.05). In conclusion, COVID-19 in hemodialysis patients associates with alteration of lymphocyte subsets, increasing of pro-inflammatory cytokines and monocyte activation. The observed worsening during the hemodialysis session in some patients was accompanied by augmentation of particular inflammatory cytokines, which might suggest biomarkers and therapeutic targets to prevent or mitigate the hemodialysis-related deterioration during SARS-CoV-2 infection.

Vaccination in patients with kidney failure: lessons from COVID-19

Infection is the second leading cause of death in patients with chronic kidney disease (CKD). Adequate humoral (antibody) and cellular (T cell-driven) immunity are required to minimize pathogen entry and promote pathogen clearance to enable infection control. Vaccination can generate cellular and humoral immunity against specific pathogens and is used to prevent many life-threatening infectious diseases. However, vaccination efficacy is diminished in patients with CKD. Premature ageing of the immune system and chronic systemic low-grade inflammation are the main causes of immune alteration in these patients. In the case of SARS-CoV-2 infection, COVID-19 can have considerable detrimental effects in patients with CKD, especially in those with kidney failure. COVID-19 prevention through successful vaccination is therefore paramount in this vulnerable population. Although patients receiving dialysis have seroconversion rates comparable to those of patients with normal kidney function, most kidney transplant recipients could not generate humoral immunity after two doses of the COVID-19 vaccine. Importantly, some patients who were not able to produce antibodies still had a detectable vaccine-specific T cell response, which might be sufficient to prevent severe COVID-19. Correlates of protection against SARS-CoV-2 have not been established for patients with kidney failure, but they are urgently needed to enable personalized vaccination regimens.

The role of neuroimmune and inflammation in pediatric uremia-induced neuropathy

Uremic neuropathy in children encompasses a wide range of central nervous system (CNS), peripheral nervous system (PNS), autonomic nervous system (ANS), and psychological abnormalities, which is associated with progressive renal dysfunction. Clinically, the diagnosis of uremic neuropathy in children is often made retrospectively when symptoms improve after dialysis or transplantation, due to there is no defining signs or laboratory and imaging findings. These neurological disorders consequently result in increased morbidity and mortality among children population, making uremia an urgent public health problem worldwide. In this review, we discuss the epidemiology, potential mechanisms, possible treatments, and the shortcomings of current research of uremic neuropathy in children. Mechanistically, the uremic neuropathy may be caused by retention of uremic solutes, increased oxidative stress, neurotransmitter imbalance, and disturbance of the blood-brain barrier (BBB). Neuroimmune, including the change of inflammatory factors and immune cells, may also play a crucial role in the progression of uremic neuropathy. Different from the invasive treatment of dialysis and kidney transplantation, intervention in neuroimmune and targeted anti-inflammatory therapy may provide a new insight for the treatment of uremia.

Vitamin D for Recovery of COVID-19 in Patients With Chronic Kidney Disease

The severity of coronavirus disease 2019 (COVID-19) is determined not only by viral damage to cells but also by the immune reaction in the host. In addition to therapeutic interventions that target the viral infection, immunoregulation may be helpful in the management of COVID-19. Vitamin D exerts effects on both innate and adaptive immunity and subsequently modulates immune responses to bacteria and viruses. Patients with chronic kidney disease (CKD) frequently have vitamin D deficiency and increased susceptibility to infection, suggesting a potential role of vitamin D in this vulnerable population. In this paper, we review the alterations of the immune system, the risk of COVID-19 infections and mechanisms of vitamin D action in the pathogenesis of COVID-19 in CKD patients. Previous studies have shown that vitamin D deficiency can affect the outcomes of COVID-19. Supplementing vitamin D during treatment may be protective against COVID-19. Future studies, including randomized control trials, are warranted to determine the effect of vitamin D supplementation on the recovery from COVID-19 in CKD patients.

Synergistic immunosuppressive effect of hispidulin and nepetin mixtures on human T lymphocytes

BACKGROUND

Clerodendrum petasites S. Moore predominantly contains hispidulin (His) and nepetin (Nep) which are immunosuppressive potentials. Although the effect of individual compounds was previously confirmed, a cumulative suppression of these flavonoid mixtures is unknown. This study thus investigated their inhibitory effects and cytotoxicity on T cells by using His:Nep ratios following a naturally-occurring dose (3:1) and optimized doses (1:1 and 1:3).

MATERIALS AND METHODS

Anti-CD3/28 stimulated peripheral blood mononuclear cells were treated with individual compounds and their mixtures. Changes in early cell activation markers in activated T cells and apoptosis were analyzed by a flow cytometer.

RESULTS

Mixtures at 3:1 suppressed CD69 and CD25 expression in CD4⁺ and CD8⁺ T cells in a dose-dependent manner. At the highest concentration of 200 µM His +66.7 µM Nep, over 90% inhibition was observed for CD25 expression in CD4⁺ and CD8⁺ T cells, whereas a lesser effect was observed for CD69 expression. A dose-dependent inhibition was still observed when using 1:1 and 1:3 ratios. Interestingly, 80-97% inhibition were observed in CD69 and CD25 expression without inducing cell death after treated with the highest doses of each ratio (66.7 µM His +200 µM Nep and 200 µM His +200 µM Nep). These mixtures were also exhibited a better suppression than individual compounds.

CONCLUSIONS

The optimized mixture of His and Nep at 66.7:200 µM is suggested for further study due to a greater suppressive effect than a single compound or a naturally-occurring dose.

T cell subpopulations and cytokine levels in hemodialysis patients

HD patients have impaired adaptive immune responses, which might depend on the primary cause of chronic kidney disease (CKD). We analyzed percentages of T cells subpopulations with the expression of CD69, CD25, CD95, and HLA-DR antigens in HD patients to determine the status of T cell activation. Also, we determined serum levels of cytokines: IL12p70, TNF, IL-10, IL-6, IL-1β, IL-8. HD patients had increased percentages of CD4⁺CD25⁺, CD4⁺CD69⁺, CD4⁺HLA-DR⁺, CD8⁺CD69⁺, and CD8⁺HLA-DR⁺ cells compared to healthy people. Also, their IL-6 and IL-8 serum levels were higher. Changes in T cell subpopulations were seen in patients with diabetic nephropathy (DN) or ischemic nephropathy (IN) but not with glomerulonephritis (GN). HD patients dialyzed for more than six months had a lower percentage of CD4⁺CD69⁺, CD8⁺HLA-DR⁺, CD8⁺CD95⁺ cells, higher IL-12p70 levels, and lower IL-8 levels. Our results show that HD treatment and CKD cause influence T cell activation status.

T-Lymphocyte Subsets Alteration, Infection and Renal Outcome in Advanced Chronic Kidney Disease

Background: T-lymphocyte subsets reflect patients' immune status and are associated with adverse outcomes in various diseases. However, the association between T-lymphocyte subsets and major infection and renal outcome in chronic kidney disease (CKD) patients has not been well-addressed.

Methods: Patients diagnosed with stage 3–5 of non-dialysis CKD were recruited, and healthy subjects were selected as the controls. T-lymphocyte subsets (CD3⁺, CD4⁺, CD8⁺) were detected by flow cytometry, and the CD4⁺/CD8⁺ T cell ratio was then calculated. Patients were divided into the normal-level group and the low-level group according to the clinical reference value. The primary outcomes were the major infection and renal outcome.

Results: A total of 410 CKD patients were enrolled; the average age was 47.25 years. Compared to the healthy controls, the level of CD3⁺, CD4⁺, CD8⁺ T cells, and the CD4⁺/CD8⁺ T cell ratio were significantly decreased in CKD patients (p < 0.05). During the median follow-up of 2.56 (quartile interval 1.24–3.46) years, major infections occurred in 15.10% of the CKD patients. The incidence of infection was significantly higher in the low-level group of CD3⁺, CD4⁺ T cells, and CD4⁺/CD8⁺ T cell ratio compared with the normal level groups. Kaplan-Meier analysis showed that the lower level of CD3⁺, CD4⁺ T cells, and CD4⁺/CD8⁺T cell ratio is associated with a greater risk of infection. Cox regression analysis further confirmed that low CD3⁺, CD4⁺ T cells, and CD4⁺/CD8⁺ T cell ratio were independent risk factors of infection in CKD patients. Moreover, during the follow-up, renal events occurred in 37.50% of patients. Kaplan-Meier analysis indicated that low levels of CD3⁺, CD4⁺, and CD8⁺ T cells are significantly associated with renal outcome in CKD patients. Cox regression analysis showed that low level of CD3⁺ T cells (HR = 2.407, 95% CI: 1.664–3.482, p < 0.001), CD4⁺ T cells (HR = 2.397, 95% CI: 1.633–3.518, p < 0.001) and CD8⁺ T cells (HR = 2.416, 95% CI: 1.476–3.955, p < 0.001) were independent risk factors for renal outcome after multivariable-adjusted.

Conclusion: CKD patients had a defect in T-lymphocyte subpopulation. T-lymphocyte subsets were closely associated with infection and renal outcome in CKD patients. Suggesting T-lymphocyte subsets are independent predictors of infection and renal outcome in CKD patients.

Hepatocellular carcinoma in patients with renal dysfunction: Pathophysiology, prognosis, and treatment challenges

The population of patients with hepatocellular carcinoma (HCC) overlaps to a high degree with those for chronic kidney disease (CKD) and end-stage renal disease (ESRD). The degrees of renal dysfunction vary, from the various stages of CKD to dialysis-dependent ESRD, which often affects the prognosis and treatment choice of patients with HCC. In addition, renal dysfunction makes treatment more difficult and may negatively affect treatment outcomes. This study summarized the possible causes of the high comorbidity of HCC and renal dysfunction. The possible mechanisms of CKD causing HCC involve uremia itself, long-term dialysis status, immunosuppressive agents for postrenal transplant status, and miscellaneous factors such as hormone alterations and dysbiosis. The possible mechanisms of HCC affecting renal function include direct tumor invasion and hepatorenal syndrome. Finally, we categorized the risk factors that could lead to both HCC and CKD into four categories: Environmental toxins, viral hepatitis, metabolic syndrome, and vasoactive factors. Both CKD and ESRD have been reported to negatively affect HCC prognosis, but more research is warranted to confirm this. Furthermore, ESRD status itself ought not to prevent patients receiving aggressive treatments. This study then adopted the well-known Barcelona Clinic Liver Cancer guidelines as a framework to discuss the indicators for each stage of HCC treatment, treatment-related adverse renal effects, and concerns that are specific to patients with pre-existing renal dysfunction when undergoing aggressive treatments against CKD and ESRD. Such aggressive treatments include liver resection, simultaneous liver kidney transplantation, radiofrequency ablation, and transarterial chemoembolization. Finally, focusing on patients unable to receive active treatment, this study compiled information on the latest systemic pharmacological therapies, including targeted and immunotherapeutic drugs. Based on available clinical studies and Food and Drug Administration labels, this study details the drug indications, side effects, and dose adjustments for patients with renal dysfunction. It also provides a comprehensive review of information on HCC patients with renal dysfunction from disease onset to treatment.

Neutralizing Antibody Responses After SARS-CoV-2 Infection in End-Stage Kidney Disease and Protection Against Reinfection

INTRODUCTION

Patients with end-stage kidney disease (ESKD) represent a vulnerable group with multiple risk factors that are associated with poor outcomes after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Despite established susceptibility to infectious complications and the importance of humoral immunity in protection against SARS-CoV-2, few studies have investigated the humoral immune response to SARS-CoV-2 within this population. Here, we evaluate the seroprevalence of SARS-CoV-2 in patients awaiting renal transplantation and determine whether seroconverted patients with ESKD have durable and functional neutralizing activity against SARS-CoV-2.

METHODS

Serum samples were obtained from 164 patients with ESKD by August 2020. Humoral immune responses were evaluated by SARS-CoV-2 spike S1 subunit and nucleoprotein semiquantitative enzyme-linked immunosorbent assay (ELISA) and SARS-CoV-2 spike pseudotype neutralization assay.

RESULTS

All patients with ESKD with reverse-transcriptase polymerase chain reaction (RT-PCR)-confirmed infection (n = 17) except for 1 individual seroconverted against SARS-CoV-2. Overall seroprevalence (anti-S1 and/or anti-N IgG) was 36% and was higher in patients on hemodialysis (44.2%). A total of 35.6% of individuals who seroconverted were asymptomatic. Seroconversion in the absence of a neutralizing antibody (nAb) titer was observed in 12 patients, all of whom were asymptomatic. Repeat measurements at a median of 93 days from baseline sampling revealed that most individuals retained detectable responses although a significant drop in S1, N and nAb titers was observed.

CONCLUSION

Patients with ESKD, including those who develop asymptomatic disease, routinely seroconvert and produce detectable nAb titers against SARS-CoV-2. Although IgG levels wane over time, the neutralizing antibodies remain detectable in most patients, suggesting some level of protection is likely maintained, particularly in those who originally develop stronger responses.

Decreased Peripheral Naïve T Cell Number and Its Role in Predicting Cardiovascular and Infection Events in Hemodialysis Patients

Patients with end-stage renal disease (ESRD) are at high risk of morbidity and mortality from cardiovascular and infectious diseases, which have been found to be associated with a disturbed immune response. Accelerated T-cell senescence is prevalent in these patients and considered a significant factor contributing to increased risk of various morbidities. Nevertheless, few studies have explicated the relevance of T-cell senescence to these fatal morbidities in ESRD patients. In this study, we designed a longitudinal prospective study to evaluate the influence of T-cell senescence on cardiovascular events (CVEs) and infections in hemodialysis (HD) patients. Clinical outcomes of 404 patients who had been on HD treatment for at least 6 months were evaluated with respect to T-cell senescence determined using flow cytometry. We found that T-cell senescence was associated with systemic inflammation. High-sensitivity C-reactive protein was positively associated with decreased naïve T cell levels. Elevated tumor necrosis factor-α and interleukin 6 levels were significantly associated with lower central memory T cell and higher T effector memory CD45RA cell levels. Decreased CD4⁺ naïve T cell count was independently associated with CVEs, whereas decreased CD8⁺ naïve T cell count was independently associated with infection episodes in HD patients. In conclusion, HD patients exhibited accelerated T-cell senescence, which was positively related to inflammation. A reduction of naïve T cell could be a strong predictor of CVEs and infection episodes in HD patients.

Longitudinal proteomic profiling of dialysis patients with COVID-19 reveals markers of severity and predictors of death

End-stage kidney disease (ESKD) patients are at high risk of severe COVID-19. We measured 436 circulating proteins in serial blood samples from hospitalised and non-hospitalised ESKD patients with COVID-19 (n = 256 samples from 55 patients). Comparison to 51 non-infected patients revealed 221 differentially expressed proteins, with consistent results in a separate subcohort of 46 COVID-19 patients. Two hundred and three proteins were associated with clinical severity, including IL6, markers of monocyte recruitment (e.g. CCL2, CCL7), neutrophil activation (e.g. proteinase-3), and epithelial injury (e.g. KRT19). Machine-learning identified predictors of severity including IL18BP, CTSD, GDF15, and KRT19. Survival analysis with joint models revealed 69 predictors of death. Longitudinal modelling with linear mixed models uncovered 32 proteins displaying different temporal profiles in severe versus non-severe disease, including integrins and adhesion molecules. These data implicate epithelial damage, innate immune activation, and leucocyte-endothelial interactions in the pathology of severe COVID-19 and provide a resource for identifying drug targets.

Systematic Review and Meta-analysis of Herpes Zoster Vaccine in Patients With CKD

Introduction

Chronic kidney disease (CKD) is a risk factor for herpes zoster (HZ) infection. Few studies have examined HZ vaccine (HZV) in this population. We conducted a systematic review and meta-analysis investigating the efficacy and safety of HZV in patients with renal disease (CKD, dialysis, and transplant).

Methods

MEDLINE, Embase, and Cochrane Central Register of Controlled Trials (CENTRAL) databases (up to May 2020) were searched for randomized controlled trials and nonrandomized controlled studies evaluating HZV in patients with CKD for effectiveness and adverse event risks. Studies without a control group (placebo or no vaccine) were excluded. Extraction of prespecified data and risk of bias assessments using the Newcastle-Ottawa scale for cohort studies and the Cochrane Risk of Bias Tool for randomized controlled trials were done by 3 authors. Random-effects meta-analysis was used to generate pooled treatment effects and 95% confidence intervals.

Results

Included were 404,561 individuals from 8 studies (3 randomized controlled trials and 5 nonrandomized). All 8 studies examined HZ as an outcome, with 3 reporting adverse events. Risk of HZ was lower in patients who received HZV compared with controls (hazard ratio, 0.55; 95% confidence interval, 0.37–0.82; P < 0.01); however, heterogeneity was high (I² = 88%, P < 0.01). There was no significant difference in adverse events associated with HZV (hazard ratio, 1.03; 95% confidence interval, 0.54–1.28; P = 0.8).

Conclusions

HZV compared with control significantly lowers the risk of HZ without an increase in adverse events in CKD patients. However, significant heterogeneity was present. HZV should be actively considered in CKD patients because the prevalence of HZ is higher in this population.

Protein-Bound Uremic Toxins and Immunity

Protein-bound uremic toxins (PBUTs) are bioactive microbiota metabolites originated exclusively from protein fermentation of the bacterial community resident within the gut microbiota, whose composition and function is profoundly different in the chronic kidney disease (CKD) population. PBUTs accumulate in the later stages of CKD because they cannot be efficiently removed by conventional hemodialysis due to their high binding affinity for albumin, worsening their toxic effects, especially at the cardiovascular level. The accumulation of uremic toxins, along with oxidative stress products and pro-inflammatory cytokines, characterizes the uremic status of CKD patients which is increasingly associated to a state of immune dysfunction including both immune activation and immunodepression. Furthermore, the links between immune activation and cardiovascular disease (CVD), and between immunodepression and infection diseases, which are the two major complications of CKD, are becoming more and more evident. This review summarizes and discusses the current state of knowledge on the role of the main PBUTs, namely indoxyl sulfate and p-cresyl sulfate, as regulators of immune response in CKD, in order to understand whether a microbiota modulation may be useful in the management of its main complications, CVD, and infections. Summarizing the direct effects of PBUT on immune system we may conclude that PCS seemed to be associated to an immune deficiency status of CKD mainly related to the adaptative immune response, while IS seemed to reflect the activation of both innate and adaptative immune systems likely responsible of the CKD-associated inflammation. However, the exact role of IS and PCS on immunity modulation in physiological and pathological state still needs in-depth investigation, particularly in vivo studies.

Outcomes of COVID-19 Among Hospitalized Patients With Non-dialysis CKD

Background: Coronavirus disease 2019 (COVID-19), caused by Severe Acute Respiratory Syndrome-Corona Virus 2 has generated significant impact on global health worldwide. COVID-19 can cause pneumonia and organ injury. Chronic kidney disease (CKD) has been associated with increased mortality in previous epidemics, but there is a paucity of data regarding actual risks for non-dialysis CKD patients with COVID-19.

Methods: Multicenter, observational cohort study including 136 non-dialysis CKD patients and 136 age- and sex-matched controls that required hospitalization due to COVID-19. Patients with end-stage renal disease, a kidney transplant or without registered baseline glomerular filtration rate prior to COVID-19 infection were excluded. CKD and acute kidney injury (AKI) were defined according to KDIGO criteria.

Results: CKD patients had higher white blood cell count and D-dimer and lower lymphocyte percentage. No differences were found regarding symptoms on admission. CKD was associated with higher rate of AKI (61 vs. 24.3%) and mortality (40.4 vs. 24.3%). Patients with AKI had the highest hazard for death (AKI/non-CKD HR:7.04, 95% CI:2.87–17.29; AKI/CKD HR:5.25, 95% CI: 2.29–12.02), followed by CKD subjects without AKI (HR:3.39, 95% CI:1.36–8.46). CKD status did not condition ICU admission or length of in-hospital stay.

Conclusions: CKD patients that require hospitalization due to COVID-19 are exposed to higher risk of death and AKI.

Current Knowledge of Vaccinations in Chronic Kidney Disease Patients

Chronic kidney disease (CKD) patients are at high risk for infectious complications. This is partly due to their dysfunctional immune system, especially in advanced CKD stages. Vaccination represents an important prevention strategy in these patients, as several studies have reported lower infection rates and significantly reduced morbidity and mortality in hospitals adopting vaccination protocols. However, vaccination rates are particularly low in these patients, and the diminished immune responsiveness remains the main issue of vaccination in CKD patients. Besides, there are various immunization protocols across the world in the absence of optimal vaccination policies. This paper aims to discuss the current knowledge of vaccination in this immunocompromised group of patients based on recent evidence and recommendations.

Coronavirus disease 2019 in chronic kidney disease

The clinical spectrum of coronavirus disease 2019 (COVID-19) infection ranges from asymptomatic infection to severe pneumonia with respiratory failure and even death. More severe cases with higher mortality have been reported in older patients and in those with chronic illness such as hypertension, diabetes or cardiovascular diseases. In this regard, patients with chronic kidney disease (CKD) have a higher rate of all-type infections and cardiovascular disease than the general population. A markedly altered immune system and immunosuppressed state may predispose CKD patients to infectious complications. Likewise, they have a state of chronic systemic inflammation that may increase their morbidity and mortality. In this review we discuss the chronic immunologic changes observed in CKD patients, the risk of COVID-19 infections and the clinical implications for and specific COVID-19 therapy in CKD patients. Indeed, the risk for severe COVID-19 is 3-fold higher in CKD than in non-CKD patients; CKD is 12-fold more frequent in intensive care unit than in non-hospitalized COVID-19 patients, and this ratio is higher than for diabetes or cardiovascular disease; and acute COVID-19 mortality is 15-25% for haemodialysis patients even when not developing pneumonia.

Molecular Mechanisms of Premature Aging in Hemodialysis: The Complex Interplay Between Innate and Adaptive Immune Dysfunction

Hemodialysis (HD) patient are known to be susceptible to a wide range of early and long-term complication such as chronic inflammation, infections, malnutrition, and cardiovascular disease that significantly affect the incidence of mortality. A large gap between the number of people with end-stage kidney disease (ESKD) and patients who received kidney transplantation has been identified. Therefore, there is a huge need to explore the underlying pathophysiology of HD complications in order to provide treatment guidelines. The immunological dysregulation, involving both the innate and adaptive response, plays a crucial role during the HD sessions and in chronic, maintenance treatments. Innate immune system mediators include the dysfunction of neutrophils, monocytes, and natural killer (NK) cells with signaling mediated by NOD-like receptor P3 (NLRP3) and Toll-like receptor 4 (TLR4); in addition, there is a significant activation of the complement system that is mediated by dialysis membrane-surfaces. These effectors induce a persistent, systemic, pro-inflammatory, and pro-coagulant milieu that has been described as inflammaging. The adaptive response, the imbalance in the CD4+/CD8+ T cell ratio, and the reduction of Th2 and regulatory T cells, together with an altered interaction with B lymphocyte by CD40/CD40L, have been mainly implicated in immune system dysfunction. Altogether, these observations suggest that intervention targeting the immune system in HD patients could improve morbidity and mortality. The purpose of this review is to expand our understanding on the role of immune dysfunction in both innate and adaptive response in patients undergoing hemodialysis treatment.

Chronic Kidney Disease-Associated Immune Dysfunctions: Impact of Protein-Bound Uremic Retention Solutes on Immune Cells

Regardless of the primary disease responsible for kidney failure, patients suffering from chronic kidney disease (CKD) have in common multiple impairments of both the innate and adaptive immune systems, the pathophysiology of which has long remained enigmatic. CKD-associated immune dysfunction includes chronic low-grade activation of monocytes and neutrophils, which induces endothelial damage and increases cardiovascular risk. Although innate immune effectors are activated during CKD, their anti-bacterial capacity is impaired, leading to increased susceptibility to extracellular bacterial infections. Finally, CKD patients are also characterized by profound alterations of cellular and humoral adaptive immune responses, which account for an increased risk for malignancies and viral infections. This review summarizes the recent emerging data that link the pathophysiology of CKD-associated immune dysfunctions with the accumulation of microbiota-derived metabolites, including indoxyl sulfate and p-cresyl sulfate, the two best characterized protein-bound uremic retention solutes.

Selected cardiovascular risk factors in early stages of chronic kidney disease

Cardiovascular diseases, including hypertension, congestive heart failure, myocardial infarction, stroke and atherosclerosis, are common in patients with chronic kidney disease. Aside from the standard biomarkers, measured to determine cardiovascular risk, new ones have emerged: markers of oxidative stress, apoptosis, inflammation, vascular endothelium dysfunction, atherosclerosis, organ calcification and fibrosis. Unfortunately, their utility for routine clinical application remains to be elucidated. A causal relationship between new markers and cardiovascular diseases in patients with chronic kidney disease remains to be established. First of all, there is a lack of large, randomized trials. Moreover, most studies focus on patients with end-stage renal disease as well as on dialysed patients. In such patients, cardiovascular diseases are already present and advanced while early detection of cardiovascular disease risk factor in patients with early-stages of chronic kidney disease would allow more precise prognosis and, as a result, changes in treatment algorithm. In this article, we conduct a comprehensive review of literature for publications relating to cardiovascular risk factors in patients with early-stages of chronic kidney disease. Overall, there are many encouraging advances in detection of cardiovascular risk factors that are making the future more promising for patients suffering from chronic kidney disease.

The difference of T cell phenotypes in end stage renal disease patients under different dialysis modality

Background

Impaired T cell immune function exists in end-stage renal disease (ESRD) patients. Dialysis treatment may lead to changes in T cell subsets. In the present study, we aimed to identify alterations of T cell phenotypes in ESRD patients, especially in those receiving peritoneal dialysis (PD), and analyze the potential associated factors.

Methods

In the present study, 110 PD patients and 110 age/gender-matched hemodialysis (HD) patients who met the inclusion criteria were studied. Pre-dialysis blood samples were obtained and analyzed by flow cytometry to detect the expression of CD45RO and CCR7. Univariate and multivariate regression analyses were used to determine the factors associated with the alteration of T cell phenotypes.

Results

In all dialysis patients, age was associated with the frequencies of both CD4+ and CD8+ naïve T cells, effector memory (EM) T cells and effector memory RA (EMRA) T cells but not central memory (CM) T cells. Dialysis modality was also associated with T cell subsets. Compared with HD patients, PD patients showed an increase in both CD4+ and CD8+ CM T cells and a reduction in both CD4+ and CD8+ EM and EMRA T cells. However, the number of CD4+ naïve T cells was lower and the number of CD8+ naïve T cells was higher in PD patients than those in HD patients. In PD patients, further multivariate analysis revealed that the frequency of CD4+ naïve T cells was positively associated with nPCR, while the frequency of CD8+ naïve T cells was negatively associated with age.

Conclusion

In dialysis patients, the dialysis modality and age influence T cell subsets. There is a progression from naïve to effector T cells in HD patients compared with PD patients. In PD patients, different factors may influence the frequencies of CD4+ and CD8+ naïve T cells.

Infectious Disease Risk in Dialysis Patients: A Transdisciplinary Approach

PURPOSE OF REVIEW

Infections are a major contributor to morbidity and mortality in end-stage renal disease (ESRD) patients. A better understanding of the interplay between infectious processes and ESRD may eventually lead to the development of targeted treatment strategies aimed at lowering overall disease morbidity and mortality. Monogenic causes are a major contributor to the development of adult chronic kidney disease (CKD). Recent studies identified a genetic cause in 10% to 20% of adults with CKD. With the introduction of whole-exome sequencing (WES) into clinical mainstay, this proportion is expected to increase in the future. Once patients develop CKD/ESRD due to a genetic cause, secondary changes, such as a compromised immune status, affect overall disease progression and clinical outcomes. Stratification according to genotype may enable us to study its effects on secondary disease outcomes, such as infectious risk. Moreover, this knowledge will enable us to better understand the molecular interplay between primary disease and secondary disease outcomes.

SOURCES OF INFORMATION

We conducted a literature review using search engines such as PubMed, PubMed central, and Medline, as well as cumulative knowledge from our respective areas of expertise.

METHODS

This is a transdisciplinary perspective on infectious complications in ESRD due to monogenic causes, such as autosomal dominant polycystic kidney disease (ADPKD), combining expertise in genomics and immunology.

KEY FINDINGS

In ADPKD, infection is a frequent complication manifesting primarily as lower urinary tract infection and less frequently as renal infection. Infectious episodes may be a direct consequence of a specific underlying structural abnormality, for example the characteristic cysts, among others. However, evidence suggests that infectious disease risk is also increased in ESRD due to secondary not-well-understood disease mechanisms. These disease mechanisms may vary depending on the underlying nature of the primary disease. While the infectious disease risk is well documented in ADPKD, there are currently insufficient data on the risk in other monogenic causes of ESRD. WES in combination with novel technologies, such as RNA sequencing and single-cell RNA sequencing, can provide insight into the molecular mechanisms of disease progression in different monogenic causes of CKD/ESRD and may lead to the development of novel risk-stratification profiles in the future.

LIMITATIONS

This is not a systematic review of the literature and the proposed perspective is tainted by the authors' point of view on the topic.

IMPLICATIONS

WES in combination with novel technologies such as RNA sequencing may enable us to fully unravel underlying disease mechanisms and secondary disease outcomes in monogenic causes of CKD and better characterize individual risk profiles. This understanding will hopefully facilitate the development of novel targeted therapies.

T Cells Play a Causal Role in Diastolic Dysfunction during Uremic Cardiomyopathy

BACKGROUND

Uremic cardiomyopathy, characterized by left ventricular hypertrophy, diastolic dysfunction, and impaired myocardial strain, contributes to increased cardiovascular mortality in patients with CKD. Emerging evidence suggests a pathogenic role for T cells during chronic heart failure.

METHODS

To determine whether T cells contribute to uremic cardiomyopathy pathogenesis, we modeled this condition by inducing CKD via 5/6th nephrectomy in mice. We used flow cytometry to assess expression of markers of T cell memory or activation by lymphocytes from CKD mice and controls, as well as lymphocyte capacity for cytokine production. Flow cytometry was also used to quantify immune cells isolated from heart tissue. To test effects of T cell depletion on cardiac function, we gave CKD mice anti-CD3 antibody injections to deplete T cells and compared heart function (assessed by echocardiography) with that of controls. Finally, we correlated T cell phenotypes with structural and functional measures on clinically acquired echocardiograms in children with CKD.

RESULTS

Mice with CKD accumulated T cells bearing markers of memory differentiation (CD44hi) and activation (PD-1, KLRG1, OX40), as reported previously in human CKD. In addition, mice with CKD showed T cells infiltrating the heart. T cell depletion significantly improved both diastolic function and myocardial strain in CKD mice without altering hypertension or degree of renal dysfunction. In children with CKD, increasing frequency of T cells bearing activation markers PD-1 and/or CD57 was associated with worsening diastolic function on echocardiogram.

CONCLUSIONS

CKD results in an accumulation of proinflammatory T cells that appears to contribute to myocardial dysfunction.

Immune Responses of HLA Highly Sensitized and Nonsensitized Patients to Genetically Engineered Pig Cells

BACKGROUND

We investigated in vitro whether HLA highly sensitized patients with end-stage renal disease will be disadvantaged immunologically after a genetically engineered pig kidney transplant.

METHODS

Blood was drawn from patients with a calculated panel-reactive antibody (cPRA) 99% to 100% (Gp1, n = 10) or cPRA 0% (Gp2, n = 12), and from healthy volunteers (Gp3, n = 10). Serum IgM and IgG binding was measured (i) to galactose-α1-3 galactose and N-glycolylneuraminic acid glycans by enzyme-linked immunosorbent assay, and (ii) to pig red blood cell, pig aortic endothelial cells, and pig peripheral blood mononuclear cell from α1,3-galactosyltransferase gene-knockout (GTKO)/CD46 and GTKO/CD46/cytidine monophosphate-N-acetylneuraminic acid hydroxylase-knockout (CMAHKO) pigs by flow cytometry. (iii) T-cell and B-cell phenotypes were determined by flow cytometry, and (iv) proliferation of T-cell and B-cell carboxyfluorescein diacetate succinimidyl ester-mixed lymphocyte reaction.

RESULTS

(i) By enzyme-linked immunosorbent assay, there was no difference in IgM or IgG binding to galactose-α1-3 galactose or N-glycolylneuraminic acid between Gps1 and 2, but binding was significantly reduced in both groups compared to Gp3. (ii) IgM and IgG binding in Gps1 and 2 was also significantly lower to GTKO/CD46 pig cells than in healthy controls, but there were no differences between the 3 groups in binding to GTKO/CD46/CMAHKO cells. (iii and iv) Gp1 patients had more memory T cells than Gp2, but there was no difference in T or B cell proliferation when stimulated by any pig cells. The proliferative responses in all 3 groups were weakest when stimulated by GTKO/CD46/CMAHKO pig peripheral blood mononuclear cell.

CONCLUSIONS

(i) End-stage renal disease was associated with low antipig antibody levels. (ii) Xenoreactivity decreased with increased genetic engineering of pig cells. (iii) High cPRA status had no significant effect on antibody binding or T-cell and B-cell response.

Immune Dysfunction and Risk of Infection in Chronic Kidney Disease

Cardiovascular disease and infections are directly or indirectly associated with an altered immune response, which leads to a high incidence of morbidity and mortality, and together, they account for up to 70% of all deaths among patients with chronic kidney dysfunction. Impairment of the normal reaction of the innate and adaptive immune systems in chronic kidney disease predisposes patients to an increased risk of infections, virus-associated cancers, and a diminished vaccine response. On the other hand, an abnormal, exaggerated reaction of the immune systems can also occur in this group of patients, resulting in increased production and decreased clearance of proinflammatory cytokines, which can lead to inflammation and its sequelae (eg, atherosclerotic cardiovascular disease). Epigenetically, modifications in hematopoietic stem cells involving a shift from lymphoid to myeloid cell lineage may underlie uremia-associated immunological senescence, which is not reversed by renal replacement therapy, including kidney transplantation. Measures aimed at attenuating the immune abnormalities in chronic kidney disease/end-stage renal disease should be an area of focused research as this could potentially lead to a better understanding and, thus, development of therapies that could reduce the disastrously high death rate in this patient population. The aim of the present article is to review the characteristics, causes, and mechanisms of the immune dysfunction related to chronic kidney disease.

A randomized trial of serological and cellular responses to hepatitis B vaccination in chronic kidney disease

BACKGROUND

Chronic kidney disease (CKD) is associated with an increased risk of hepatitis B infection and impaired seroconversion to hepatitis B vaccine (HBV). Studies examining augmented vaccine schedules to enhance seroconversion have so far been inconclusive. Furthermore, the defects responsible for impaired vaccine immunity in CKD have not yet been identified.

METHODS

We studied serological and cellular responses to HBV in CKD to identify a defect in vaccine-induced cellular responses that could account for impaired seroconversion in CKD and clarify the effects of an augmented vaccine dose schedule. We compared these results with responses to seasonal influenza vaccination (Fluvax).

RESULTS

We found a clear benefit in rates and magnitude of seroconversion after an augmented 40mcg HBV dose schedule in CKD. This permitted comparison of responders and non-responders. Serological non-responders with CKD exhibited reduction in CXCR3+CCR6- CXCR5+ memory T cells at baseline. Unlike Fluvax, HBV elicited a poor plasmablast (PB) response. Both vaccinations induced activation of the CXCR3+CCR6- CCR7- subset of circulating T follicular helper cells (cTFH), although this response was impaired in CKD after HBV.

CONCLUSIONS

CKD confers a specific T cell defect that contributes to the impaired seroconversion to HBV.

Clinical epidemiology of infectious disease among patients with chronic kidney disease

Infectious disease is recognized as an important complication among patients with end-stage renal disease, contributing to excess morbidity and health care costs. However, recent epidemiological studies have revealed that even mild to moderate stages of chronic kidney disease (CKD) substantially increase risk of infection. Regarding underlying mechanisms, evidence suggests various aspects of altered immune response in patients with CKD including impaired function of T cells, B cells and neutrophil. Multiple conditions surrounding CKD, such as older age, diabetes, and cardiovascular disease are important contributors in the increased susceptibility to infection in this population. In addition, several mechanisms impairing immune function have been hypothesized including accumulated uremic toxins, increased oxidative stress, endothelial dysfunction, low-grade inflammation, and mineral and bone disorders. In terms of prevention strategies, influenza and pneumococcal vaccines are most feasible and important. Nevertheless, the extent of vaccine utilization in CKD has not been well documented. In addition, antibody response to vaccination may be reduced in CKD patients, and thus a vaccine delivery strategy (e.g., dose and frequency) may need to be optimized among patients with CKD. Through this review, we demonstrate that infection is a major but underrecognized complication of CKD. As CKD is recognized as a serious public health issue, dedicated research is needed to better characterize the burden of infectious disease associated with CKD, understand the pathophysiology of infection in patients with CKD, and develop effective strategies to prevent infection and its sequela in this high risk population.

End-stage renal disease, dialysis, kidney transplantation and their impact on CD4+ T-cell differentiation

Premature aging of both CD4⁺ regulatory T (Treg) and CD4⁺ responder-T (Tresp) cells in patients with end-stage renal disease (ESRD) is expected to affect the success of later kidney transplantation. Both T-cell populations are released from the thymus as inducible T-cell co-stimulator-positive (ICOS⁺ ) and ICOS^- recent thymic emigrant (RTE) Treg/Tresp cells, which differ primarily in their proliferative capacities. In this study, we analysed the effect of ESRD and subsequent renal replacement therapies on the differentiation of ICOS⁺ and ICOS^- RTE Treg/Tresp cells into ICOS⁺  CD31^- or ICOS^-  CD31^- memory Treg/Tresp cells and examined whether diverging pathways affected the suppressive activity of ICOS⁺ and ICOS^- Treg cells in co-culture with autologous Tresp cells. Compared with healthy controls, we found an increased differentiation of ICOS⁺ RTE Treg/Tresp cells and ICOS^- RTE Treg cells through CD31⁺ memory Treg/Tresp cells into CD31^- memory Treg/Tresp cells in ESRD and dialysis patients. In contrast, ICOS^- RTE Tresp cells showed an increased differentiation via ICOS^- mature naive (MN) Tresp cells into CD31^- memory Tresp cells. Thereby, the ratio of ICOS⁺ Treg/ICOS⁺ Tresp cells was not changed, whereas that of ICOS^- Treg/ICOS^- Tresp cells was significantly increased. This differentiation preserved the suppressive activity of both Treg populations in ESRD and partly in dialysis patients. After transplantation, the increased differentiation of ICOS⁺ and ICOS^- RTE Tresp cells proceeded, whereas that of ICOS⁺ RTE Treg cells ceased and that of ICOS^- RTE Treg cells switched to an increased differentiation via ICOS^- MN Treg cells. Consequently, the ratios of ICOS⁺ Treg/ICOS⁺ Tresp cells and of ICOS^- Treg/ICOS^- Tresp cells decreased significantly, reducing the suppressive activity of Treg cells markedly. Our data reveal that an increased tolerance-inducing differentiation of ICOS⁺ and ICOS^- Treg cells preserves the functional activity of Treg cells in ESRD patients, but this cannot be maintained during long-term renal replacement therapy.

Factors associated with the elevated percentage of CD4CD69 T cells in maintained hemodialysis patients

Background: CD4 T-cell abnormality, influencing the outcome of the maintained hemodialysis (MHD), is common in patients on dialysis. We try to find out factors associated with the activated CD4 T cells, CD4CD69 T cells, to improve the dialysis quality.

Methods: A cross-sectional study was conducted to evaluate the change of CD4CD69 in MHD patients and healthy controls in our hospital from September 2015 to May 2016. A total of 164 MHD patients and 24 healthy controls were included according to the criteria. Univariate and multivariate logistic regression models after correlation analysis were executed to discover the related factors of CD4CD69 T-cell posterior to the division of the CD4CD69 T cell according to its median.

Results: The lymphocytes were lower, but the percentage of CD4CD69 T cells was higher in MHD patients compared with healthy controls, even after the propensity score matching based on age and sex. The percentage of CD4 T cells showed no significant difference between the two groups. Further multivariate logistic regression models revealed that CD4CD69 T cell was independently associated with serum total protein (OR 95%CI: 0.830[0.696, 0.990], p = .038), transferrin (OR 95%CI: 3.072[1.131, 8.342], p = .028) and magnesium (OR 95%CI: 16.960[1.030, 279.275], p = .048).

Conclusion: The percentage of CD4CD69 T cells, activated CD4 T cells, elevated in hemodialysis patients despite the decrease in lymphocytes. The elevated CD4CD69 T cells were independently associated with serum total protein negatively, but transferrin and magnesium positively. Strengthening nutrition, reducing the concentration of transferrin and magnesium might be beneficial to reduce the activation of CD4 T cells and improve the outcome of MHD patients.

Indoxyl sulfate (IS)-mediated immune dysfunction provokes endothelial damage in patients with end-stage renal disease (ESRD)

Progressive renal failure causes uremia-related immune dysfunction, which features a chronic inflammatory milieu. Given the central role of end-stage renal disease (ESRD)-related immune dysfunction in the pathogenesis of cardiovascular diseases (CVDs), much attention has been focused on how uremic toxins affect cellular immunity and the mechanisms underlying pathogenesis of atherosclerosis in ESRD patients. Here, we investigated the characteristics of monocytes and CD4+ T cells in ESRD patients and the immune responses induced by indoxyl sulfate (IS), a key uremic toxin, in order to explore the pathogenic effects of these cells on vascular endothelial cells. In ESRD patients, monocytes respond to IS through the aryl hydrocarbon receptor (AhR) and consequently produce increased levels of TNF-α. Upon stimulation with TNF-α, human vascular endothelial cells produce copious amounts of CX3CL1, a chemokine ligand of CX3CR1 that is highly expressed on CD4+CD28-T cells, the predominantly expanded cell type in ESRD patients. A migration assay showed that CD4+CD28- T cells were preferentially recruited by CX3CL1. Moreover, activated CD4+CD28- T cells exhibited cytotoxic capability allowing for the induction of apoptosis in HUVECs. Our findings suggest that in ESRD, IS-mediated immune dysfunction may cause vascular endothelial cell damage and thus, this toxin plays a pivotal role in the pathogenesis of CVD.

The effect of chronic kidney disease on T cell alloimmunity

PURPOSE OF REVIEW

Altered differentiation and activation of T-cell subsets occur in patients with chronic kidney disease (CKD), but the impact on graft rejection and protective immunity during transplantation are not fully understood.

RECENT FINDINGS

Patients with CKD have decreased frequency of naïve T cells, accumulation of activated, terminally differentiated memory cells, and skewed regulatory versus T helper 17 ratio. Naïve and memory T-cell subsets do not appear to improve following kidney transplantation. Retained thymic output is associated with acute rejection, whereas naïve lymphopenia and accumulation of CD8 TEMRA cells correlate with long-term graft dysfunction. CD28 memory cells accumulate during CKD and appear to confer protection against acute rejection under standard immunosuppression and possibly costimulation blockade. T cells bearing CD57 are also increased in patients with CKD and may underlie rejection during costimulation blockade.

SUMMARY

The mechanisms by which CKD alters the differentiation and activation status of T-cell subsets is poorly understood. Further research is also needed to understand which cell populations mediate rejection under various immunosuppressive regimens. To date, there is little use of animal models of organ failure in transplant immunology research. CKD mouse models may help identify novel pathways and targets to better control alloimmunity in posttransplant.

Latency for cytomegalovirus impacts T cell ageing significantly in elderly end-stage renal disease patients

The number of elderly patients with end-stage renal disease (ESRD) has increased significantly during the last decade. Elderly ESRD patients are vulnerable to infectious complications because of an aged immune system. Additional immunological ageing effects may be derived from the uraemic environment and cytomegalovirus (CMV) latency. Elderly patients may be affected by these factors in particular, but data in this age group are limited. To assess the degree of immunological ageing and proliferative capacity of T lymphocytes, 49 elderly ESRD patients (defined as aged ≥ 65 years) on the renal transplantation waiting list were recruited and compared to 44 elderly healthy individuals (HI), matched for age and CMV serostatus. CMV latency was associated with more highly differentiated CD4⁺ and CD8⁺ T cells in both elderly HI and patients. Elderly CMV seropositive ESRD patients showed a substantial reduction in the number of naive CD4⁺ and CD8⁺ T cells compared with age- and CMV serostatus-matched HI. Elderly ESRD patients also showed significantly decreased numbers of central memory CD4⁺ and CD8⁺ T cells compared with HI, independently of CMV serostatus. In addition, thymic output and relative telomere length of both CD4⁺ and CD8⁺ T cells were decreased in CMV seropositive ESRD patients compared with HI. The proliferative capacity of T cells was similar for patients and HI. Elderly ESRD patients have an advanced aged T cell compartment when compared to age-matched healthy controls, which is driven mainly by CMV latency.

Lymphocyte depletion and subset alteration correlate to renal function in chronic kidney disease patients

BACKGROUND

It is widely accepted that chronic renal failure is associated with severe alterations of immune system. However, few studies looked into the immune alteration in earlier stage of chronic kidney disease (CKD) patients. To characterize immune defect in CKD patients, we performed lymphocyte subset analysis and explored its relationship to renal function in this population.

METHODS

472 CKD patients were enrolled in this study. Lymphocyte subsets (CD19(+), CD3(+), CD3(+)CD4(+), CD3(+)CD8(+), CD56(+)CD16(+)) were determined by flow cytometry. Clinical and laboratory data were collected. Patterns of immune cells in different stages of CKD were compared. Multivariate linear regression was used to evaluate the relationship between lymphocyte subset group and renal function. Correlation analysis was used to assess the relationship between lymphocyte subset and other clinical and laboratory data.

RESULTS

Decreased lymphocyte counts occurred long before the end stage of renal disease. Increased NK cell percentage was negatively related to estimated glomerular filtration rate (eGFR) (r = -0.259, p < 0.001) while B cell percentage was positively related to eGFR (r = 0.249, p < 0.001). Further multivariate linear regression showed increased B cell percentage (β = 16.470, 95%CI [1.018-31.922], p = 0.037) and decreased NK cell percentage (β = -10.659, 95%CI [-20.063 to -1.254], p = 0.026) were independently correlated with higher eGFR, respectively. Patients with lower NK cell percentage and higher B cell percentage tended to have the best renal function.

CONCLUSIONS

Lymphocyte depletion and subset alteration occurred during the progress of CKD. Further studies are needed to clarify the role of immune system in CKD and to expand our knowledge about the effect of uremia on the structure and function of immune system.

Study of peripheral blood natural killer cells, T-cell helper/T-cell suppressor ratio and intercurrent infection frequency in hepatitis C seropositive prevalent hemodialysis patients

Hemodialysis (HD) may adversely affect the immune system. It is established that intercurrent infection rate and severity may be increased in prevalent HD patients. Moreover, hepatitis C viral infection, a common infection in many HD centers, may further inhibit the immune system. To our knowledge, no previous study in the literature has attempted to investigate the possible effects of hepatitis C seropositivity on rate and severity of intercurrent infection in prevalent HD patients. The aim of this study was to assess the peripheral blood CD16-natural killer cells, CD4/CD8 ratio, as well as rate of intercurrent infection in hepatitis C seropositive prevalent HD patients as compared with hepatitis C seronegative prevalent HD patients. Twenty hepatitis C seropositive stable prevalent HD patients (group A), as well as another twenty hepatitis C seronegative stable prevalent HD patients (group B), were randomly selected from our HD unit and enrolled in the study. Both groups were similar in age, sex, body mass index, and duration of HD. Diabetics, smokers, and cases with advanced liver disease (Child classification stages B and C) were excluded from the study. A third group (group C) of 10 apparently healthy subjects (of similar age, sex, and body mass index), was also enrolled in the study. All subjects were investigated by complete blood count, routine chemistry, assessment of peripheral lymphocytes CD3,CD16, CD4, CD8, CD4/CD8 ratio by flow cytometer, as well assessment of intercurrent infection frequency retrospectively (since the start of HD therapy and seroconversion in HD patients, and prospectively for a period of six months. Although we detected statistically significant higher frequency of intercurrent infection in both HD groups compared with the healthy group, we did not detect significant differences between hepatitis C seropositive and seronegative groups regarding frequency or severity of intercurrent infection. Moreover, we did not detect significant differences among the three studied groups regarding levels of CD16, CD3, CD4, CD8, CD4/CD8 ratio in peripheral lymphocytes. It may be concluded that hepatitis C seropositive prevalent HD patients are not at increased risk of intercurrent infection as compared with hepatitis C seronegative prevalent HD patients, contrary to what is reported in hepatitis C seroconverted organ transplant candidates.

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.

Lymphocyte populations and apoptosis of peripheral blood B and T lymphocytes in children with end stage renal disease

BACKGROUND

End stage renal disease (ESRD) is a worldwide devastating health problem due to its increased prevalence in the population and high association with several pathologic conditions including immunodeficiency, which makes a significant contribution to morbidity and mortality.

AIM

The present study aimed at analysis of T and B lymphocyte subpopulation and the detection of flowcytometric apoptosis markers on peripheral B and T lymphocytes in a cohort of children with ESRD.

SUBJECTS AND METHODS

A case-control study was conducted on 28 children with ESRD. In addition, 30 age and sex matched healthy children were included as a control group. We used Annexin V-FITC binding assay as a sensitive probe for identifying cells undergoing apoptosis.

RESULTS

Circulating neutrophils, T and B lymphocytes were lower in patient group. In addition, apoptotic B and T lymphocytes occurred more frequently in children with ESRD than in the control group.

CONCLUSION

Our finding of low numbers of circulating neutrophils, T and B lymphocytes, and increased portion of apoptotic B and T lymphocytes in children with ESRD, may emphasize the fact that these derangements are the main mechanisms responsible for the impairment of the immune system in ESRD children, also it adds to the fact that both cellular and humoral immunity affected in ESRD children. Finally, uremia and increased peripheral lymphocyte apoptosis were the major causes of lymphocyte populations' depletion in our ESRD patients.

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.

Modulation of LPS-induced CD4+ T-cell activation and apoptosis by antioxidants in untreated asymptomatic HIV infected participants: an in vitro study

Persistent immune activation characterises HIV infection and is associated with depletion of CD4+ T-cells and increased risk of disease progression. Early loss of gut mucosal integrity results in the translocation of microbial products such as lipopolysaccharide (LPS) into the systemic circulation. This is an important source of on-going immune stimulation. The purpose of this study was to determine levels of CD4+ T-cell activation (%CD25 expression) and apoptosis (% annexin V/7-AAD) in asymptomatic, untreated HIV infection at baseline and after stimulation with LPS and incubation with or without vitamin C and N-acetylcysteine. LPS induced a significant (P < 0.03) increase in %CD25 expression, annexin V, and 7-AAD in HIV positive individuals. NAC in combination with vitamin C, significantly (P = 0.0018) reduced activation and early apoptosis of CD4+ T-cells to a greater degree than with either antioxidant alone. Certain combinations of antioxidants could be important in reducing the harmful effects of chronic immune activation and thereby limit CD4+ T-cell depletion. Importantly, we showed that CD4+ T-cells of the HIV positive group responded better to a combination of the antioxidants at this stage than those of the controls. Therefore, appropriate intervention at this asymptomatic stage could rescue the cells before repetitive activation results in the death of CD4+ T-cells.

Deregulation from CD4+ memory T cells to regulatory cells in patients with chronic renal failure: a pilot study

BACKGROUND

The aim of this study was to elucidate whether the CD4+ memory T (Tm) cells differentiation to regulatory T cells (Tregs) play a role in the immunological defects in patients with chronic kidney disease (CKD), and if the oxidized low-density lipoprotein (oxLDL) had affect on on CD4+ Tm cells and Tregs apoptosis in these subjects.

METHODS

CD4+ Tm cells and Tregs were detected by flow cytometry in each group of ten subjects. Apoptosis was measured by flow cytometry and confirmed by Western blotting.

RESULTS

The oxLDL concentration was significantly higher in CKD stage 4 (CKD4) patients than in controls, particularly in hemodialysis (HD) subjects (P < 0.001, respectively). In total, 100 μg/ml oxLDL significantly inhibited the CD4+ Tm cell proliferation. oxLDL-induced Tm generated Tregs apoptosis in controls and CKD4 patients, especially in HD patients (P < 0.001, respectively).

CONCLUSION

Dysregulation of CD4+ Tm cells converting into Tregs played a role in the immune defects of CKD patients, and oxLDL induced the apoptosis of Tm generating Tregs in these subjects. Larger size of sample should be investigated to confirm the findings in further studies.