ESRD-associated immune phenotype depends on dialysis modality and iron status: clinical implications

Characteristics of T cell premature senescence in maintenance hemodialysis patients

BACKGROUND

Uremia-associated immunodeficiency, mainly characterized by T cell dysfunction, exists in patients on maintenance hemodialysis (MHD) and promotes systemic inflammation. However, T cell senescence, one of the causes of T cell dysfunction, has not been clearly revealed yet. In this cross-sectional research, we aimed to study the manifestation of T cell premature senescence in MHD patients and further investigate the associated clinical factors.

METHODS

76 MHD patients including 33 patients with cardiovascular diseases (CVD) and 28 patients with arteriovenous fistula (AVF) event history were enrolled in this study. Complementarity determining region 3 (CDR3) of T cell receptor (TCR) was analyzed by immune repertoire sequencing (IR-Seq). CD28- T cell subsets and expression of senescence marker p16 and p21 genes were detected by multicolor flow cytometry and RT-qPCR, respectively.

RESULTS

MHD patients had significantly decreased TCR diversity (P < 0.001), increased CDR3 clone proliferation (P = 0.001) and a left-skewed CDR3 length distribution. The proportion of CD4 + CD28- T cells increased in MHD patients (P = 0.014) and showed a negative correlation with TCR diversity (P = 0.001). p16 but not p21 expression in T cells was up-regulated in MHD patients (P = 0.039). Patients with CVD exhibited increased expression of p16 and p21 genes (P = 0.010 and 0.004, respectively), and patients with AVF events showed further TCR diversity and evenness reduction (P = 0.002 and 0.017, respectively) compared to patients without the comorbidities. Moreover, age, average convection volume, total cholesterol, high-density lipoprotein cholesterol and transferrin saturation were associated with TCR diversity or CD4 + CD28- T cell proportion (P < 0.05).

CONCLUSIONS

MHD patients undergo T cell premature senescence characterized by significant TCR diversity reduction and repertoire skew, as well as accumulation of the CD4 + CD28- subset and up-regulation of p16 gene. Patients with CVD or AVF events show higher level of immunosenescence. Furthermore, T cell senescence in MHD patients is associated with blood cholesterol and uremic toxin retention, suggesting potential intervention strategies in the future.

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.

Levels of Cell-Free DNA in Kidney Failure Patients before and after Renal Transplantation

Circulating cell-free DNA (cfDNA) has diverse applications in oncological, prenatal, toxicological, cardiovascular, and autoimmune diseases, diagnostics, and organ transplantation. In particular, mitochondrial cfDNA (mt-cfDNA) is associated with inflammation and linked to early vascular ageing (EVA) in end-stage kidney failure (ESKF), which could be a noninvasive marker for graft rejection and organ damage. Plasma samples from 44 ESKF patients, of whom half (n = 22) underwent either conservative therapy (non-HD) or hemodialysis (HD) before kidney transplantation (KT). These samples were analyzed at baseline and two years after KT. cfDNA was extracted from plasma and quantified using the fluorometric method. qPCR was used to quantify and differentiate the fractions of mt-cfDNA and nuclear cfDNA (nc-cfDNA). mt-cfDNA levels in KT patients decreased significantly from baseline to two years post-KT (p < 0.0268), while levels of total cfDNA and nc-cfDNA did not differ. Depending on therapy modality (HD vs. non-HD) before KT, total cfDNA levels were higher in HD patients at both baseline (p = 0.0133) and two years post-KT (p = 0.0421), while nc-cfDNA levels were higher in HD only at baseline (p = 0.0079). Males showed a nonsignificant trend of higher cfDNA levels. Patients with assessed vascular fibrosis (p = 0.0068), either alone or in combination with calcification plus fibrosis, showed reduced mt-cfDNA post-KT (p = 0.0195). Changes in mt-cfDNA levels suggests the impact of KT on the inflammatory state of ESKF, as evidenced via its correlation with high sensitivity C-reactive protein after KT. Further studies are warranted to assess if cfDNA could serve as a noninvasive method for monitoring the response to organ transplantation and even for amelioration of EVA status per se.

Immunosenescence and Immune Exhaustion Are Associated with Levels of Protein-Bound Uremic Toxins in Patients on Hemodialysis

BACKGROUND

The accumulation of protein-bound uremic toxins (PBUTs) in chronic kidney disease may affect patients' immune status. The aim of the study was to evaluate their potential impacts on lymphocyte alterations in patients on hemodialysis (HD).

METHODS

The plasma levels of PBUTs were assessed in 54 patients on HD and 31 healthy individuals, using ultra-performance liquid chromatography. The results correlated with the senescent and exhausted status of lymphocytes, based on certain surface molecules, analyzed by flow cytometry.

RESULTS

The plasma levels of PBUTs were significantly increased in the patients on HD compared with the healthy controls. The patients with residual kidney function had reduced hippuric acid (HA) levels, total (p = 0.03) and free (p = 0.04), and free IxS levels (p = 0.02). The total and free HA levels correlated negatively with less differentiated subpopulations, CD4+CD45RA+CD31+ (p = 0.037 and p = 0.027), CD8+CD28+CD57- (p = 0.01, p = 0.01), and naïve B cells (CD19+IgD+CD27-) (p = 0.04, p = 0.03). Both the total and the free pCS levels correlated positively with exhausted CD4 cells, p = 0.02 and p = 0.01, respectively. A multivariate analysis showed that IxS and age were the main independent parameters implicated in the reduction intotal CD4 and B lymphocytes and their naïve and early differentiated subsets.

CONCLUSIONS

Increased PBUTs levels are associated with immune disturbances of patients on HD, HA, and IxS in the immunosenescent and pCS in the immunoexhaustion alterations.

Bioinformatics led discovery of biomarkers related to immune infiltration in diabetes nephropathy

BACKGROUND

The leading cause of end-stage renal disease is diabetic nephropathy (DN). A key factor in DN is immune cell infiltration (ICI). It has been shown that immune-related genes play a significant role in inflammation and immune cell recruitment. However, neither the underlying mechanisms nor immune-related biomarkers have been identified in DNs. Using bioinformatics, this study investigated biomarkers associated with immunity in DN.

METHODS

Using bioinformatic methods, this study aimed to identify biomarkers and immune infiltration associated with DN. Gene expression profiles (GSE30528, GSE47183, and GSE104948) were selected from the Gene Expression Omnibus database. First, we identified 23 differentially expressed immune-related genes and 7 signature genes, LYZ, CCL5, ALB, IGF1, CXCL2, NR4A2, and RBP4. Subsequently, protein-protein interaction networks were created, and functional enrichment analysis and genome enrichment analysis were performed using the gene ontology and Kyoto Encyclopedia of Genes and Genome databases. In the R software, the ConsensusClusterPlus package identified 2 different immune modes (cluster A and cluster B) following the consistent clustering method. The infiltration of immune cells between the 2 clusters was analyzed by applying the CIBERSORT method. And preliminarily verified the characteristic genes through in vitro experiments.

RESULTS

In this study, the samples of diabetes nephropathy were classified based on immune related genes, and the Hub genes LYZ, CCL5, ALB, IGF1, CXCL2, NR4A2 and RBP4 related to immune infiltration of diabetes nephropathy were obtained through the analysis of gene expression differences between different subtypes.

CONCLUSIONS

This study was based on bioinformatics technology to analyze the biomarkers of immune related genes in diabetes nephropathy. To analyze the pathogenesis of diabetes nephropathy at the RNA level, and ultimately provide guidance for disease diagnosis, treatment, and prognosis.

Characterization of the Human Blood Virome in Iranian Multiple Transfused Patients

Blood transfusion safety is an essential element of public health. Current blood screening strategies rely on targeted techniques that could miss unknown or unexpected pathogens. Recent studies have demonstrated the presence of a viral community (virobiota/virome) in the blood of healthy individuals. Here, we characterized the blood virome in patients frequently exposed to blood transfusion by using Illumina metagenomic sequencing. The virome of these patients was compared to viruses present in healthy blood donors. A total number of 155 beta-thalassemia, 149 hemodialysis, and 100 healthy blood donors were pooled with five samples per pool. Members of the Anelloviridae and Flaviviridae family were most frequently observed. Interestingly, samples of healthy blood donors harbored traces of potentially pathogenic viruses, including adeno-, rota-, and Merkel cell polyomavirus. Viruses of the Anelloviridae family were most abundant in the blood of hemodialysis patients and displayed a higher anellovirus richness. Pegiviruses (Flaviviridae) were only observed in patient populations. An overall trend of higher eukaryotic read abundance in both patient groups was observed. This might be associated with increased exposure through blood transfusion. Overall, the findings in this study demonstrated the presence of various viruses in the blood of Iranian multiple-transfused patients and healthy blood donors.

The Situation and Influencing Factors of Depression and Anxiety in Patients of Hemodialysis during the COVID-19 Pandemic in China

OBJECTIVE

To investigate the incidence of depression and anxiety among maintenance hemodialysis (MHD) patients during the regular prevention and control stage of COVID-19 in China as well as the influencing factors.

METHODS

A cross-sectional study including 180 patients under the treatment of hemodialysis was conducted in the hemodialysis center of the 8th Affiliated Hospital of Sun Yat-Sen University. The questionnaire regarding the subject's general information, Self-Rating Anxiety Scale (SAS) and Self-Rating Depression Scale (SDS) was completed by the patients, and the laboratory test results were recorded.

RESULTS

The incidences of anxiety and depression were 35.6% and 38.9%, respectively, and the average scores of SAS and SDS were (48.03 ± 5.02) and (48.12 ± 5.42), respectively, in the subjects. The results showed that age, monthly income, vascular access of dialysis, feeling of pain and itching (within a week), worried about being infected by COVID-19, whether having health insurance and the levels of hemoglobin, parathyroid hormone, and phosphorus were the impact factors of both anxiety and depression in the MHD patients (p < 0.05 for all).

CONCLUSION

The proportion of depression and anxiety is relatively high in the MHD patients during the regular prevention and control stage of COVID-19.

Free Light Chains, High Mobility Group Box 1, and Mortality in Hemodialysis Patients

Background: Uremic toxins are associated with immune dysfunction and inflammation. The inadequate removal by hemodialysis (HD) of serum free light chains (FLCs) determines their accumulation. This study evaluated FLCs in HD patients, analyzing their relations with other biomarkers, such as serum high mobility group box 1 (HMGB1). Methods: FLC and HMGB1 were evaluated in a cohort of 119 HD patients. κFLC and λFLC were summated to give a combined (c) FLC concentration. Patients were followed prospectively until the end of the observation period of four years, or until the endpoint: the patient’s death. Results: cFLC values in HD patients were 244.4 (197.9−273.5) mg/L. We detected a significant reduction in CD8+ cells and a decreased CD4+/CD8+ ratio. HMGB1 levels were 94.5 (55−302) pg/mL. After multivariate analysis, cFLCs correlated with β2-microglobulin and the CD4+/CD8+ ratio. Subjects with cFLC values above 263 mg/L and with sHMGB1 values < 80 pg/mL experienced a significantly faster evolution to the endpoint (mean follow-up time to progression of 27.5 and 28.5 months, respectively; p < 0.001). After an adjusted multivariate Cox analysis, cFLCs were associated with 11% increased risk of death, whereas low sHMGB1 increased this risk by 5%. Conclusions: cFLCs and HMGB1 reflect the inflammation and immune dysfunction in HD patients representing two strong and independent risk markers of mortality.

COVID-19 Vaccination in Kidney Transplant Candidates and Recipients

Kidney transplant candidates and kidney transplant recipients (KTRs) are at particular risk of severe complications of COVID-19 disease. In Western countries, mortality in affected hospitalized KTRs ranges between 19% and 50%. COVID-19 vaccination remains the most important measure to prevent the severity of infection in candidates and recipients of kidney transplant. However, the uraemic condition may affect the vaccine-induced immunity in patients with advanced chronic kidney disease (CKD) and in KTRs. Retention of uraemic toxins, dysbiosis, dysmetabolism, and dialysis can diminish the normal response to vaccination, leading to dysfunction of inflammatory and immune cells. In KTRs the efficacy of vaccines may be reduced by the immunosuppressive medications, and more than half of kidney transplant recipients are unable to build an immune response even after four administrations of anti-COVID-19 vaccines. The lack of antibody response leaves these patients at high risk for SARS-CoV-2 infection and severe COVID-19 disease. The aim of the present review is to focus on the main reasons for the impaired immunological response among candidates and kidney transplant recipients and to highlight some of the present options available to solve the problem.

Local and Systemic Immunity Are Impaired in End-Stage-Renal-Disease Patients Treated With Hemodialysis, Peritoneal Dialysis and Kidney Transplant Recipients Immunized With BNT162b2 Pfizer-BioNTech SARS-CoV-2 Vaccine

Vaccination against COVID-19 in patients with end-stage renal disease (ESRD) on replacement therapy and kidney transplant recipients (KTRs) is particularly important due to the high mortality rate. Here, we tested the local and systemic immunity to the novel Pfizer BioNTech (BNT162b2) messenger RNA (mRNA) in ESRD, KTR patients, and healthy individuals (150 subjects). The ESRD group was divided into: hemodialysis (HD) and peritoneal dialysis (PD). We investigated the local and systemic immunity based on anti-N (nucleoprotein) and anti-S (spike1/2) Immunoglobulin A (IgA) and Immunoglobulin G (IgG) antibodies, respectively. Additionally, we performed an Interferon gamma (IFN-γ) release test Interferon-gamma release assay (IGRA) to monitor the cellular component of vaccine response. The control group had the highest level of anti-S IgG antibodies (153/2,080 binding antibody units (BAU)/ml) among all analyzed patients after the 1st and 2nd dose, respectively. The HD group (48/926 BAU/ml) had a diminished antibody level compared to PD (93/1,607 BAU/ml). Moreover, the seroconversion rate after the 1st dose was lower in HD than PD (56% vs. 86%). KTRs had extremely low seroconversion (33%). IgA-mediated immunity was the most effective in the control group, while other patients had diminished IgA production. We observed a lower percentage of vaccine responders based on the IFN-γ level in all research participants (100% vs. 85% in control, 100% vs. 80% in PD, 97% vs. 64% in HD). 63% of seropositive KTRs had a positive IGRA, while 28% of seronegative patients produced IFN-γ. Collectively, PD patients had the strongest response among ESRD patients. Two doses of the Pfizer vaccine are ineffective, especially in HD and KTRs. A closer investigation of ESRD and KTRs is required to set the COVID-19 vaccine clinical guidance.

Single-Cell RNA and ATAC Sequencing Reveal Hemodialysis-Related Immune Dysregulation of Circulating Immune Cell Subpopulations

Background

An increased risk of infection, malignancy, and cardiovascular diseases in maintenance hemodialysis patients is associated with hemodialysis-related immunity disturbances. Although defects in T-lymphocyte-dependent immune responses and preactivation of antigen-presenting cells have been documented in hemodialysis patients, the effects of long-term hemodialysis on the transcriptional program and chromosomal accessibility of circulating immune cell subpopulations remain poorly defined.

Methods

We integrated single-cell RNA sequencing (scRNA-seq) and single-cell assay for transposase-accessible chromatin sequencing (scATAC-seq) to characterize the transcriptome profiles of peripheral mononuclear cells (PBMCs) from healthy controls and maintenance hemodialysis patients. Validation of differentially expressed genes in CD4+ T cells and monocytes were performed by magnetic bead separation and quantitative real-time PCR.

Results

We identified 16 and 15 PBMC subgroups in scRNA-seq and scATAC-seq datasets, respectively. Hemodialysis significantly suppressed the expression levels of T cell receptor (TCR) genes in CD4+ T cell subsets (e.g., TRAV4, CD45, CD3G, CD3D, CD3E) and major histocompatibility complex II (MHC-II) pathway-related genes in monocytes (HLA-DRB1, HLA-DQA2, HLA-DQA1, HLA-DPB1). Downstream pathways of TCR signaling, including PI3K-Akt-mTOR, MAPK, TNF, and NF-κB pathways, were also inhibited in CD4+ T cell subpopulations during the hemodialysis procedure. Hemodialysis altered cellular communication patterns between PBMC subgroups, particularly TGF-TGFBR, HVEM-BTLA, and IL16-CD4 signalings between CD4+ T cells and monocytes. Additionally, we found that hemodialysis inhibited the expression of AP-1 family transcription factors (JUN, JUND, FOS, FOSB) by interfering with the chromatin accessibility profile.

Conclusions

Our study provides a valuable framework for future investigations of hemodialysis-related immune dysregulation and identifies potential therapeutic targets for reconstituting the circulating immune system in maintenance hemodialysis patients.

Erythropoiesis-independent effects of iron in chronic kidney disease

Chronic kidney disease (CKD) leads to alterations of iron metabolism, which contribute to the development of anemia and necessitates iron supplementation in patients with CKD. Elevated hepcidin accounts for a significant iron redistribution in CKD. Recent data indicate that these alterations in iron homeostasis coupled with therapeutic iron supplementation have pleiotropic effects on many organ systems in patients with CKD, far beyond the traditional hematologic effects of iron; these include effects of iron on inflammation, oxidative stress, kidney fibrosis, cardiovascular disease, CKD-mineral and bone disorder, and skeletal growth in children. The effects of iron supplementation appear to be largely dependent on the route of administration and on the specific iron preparation. Iron-based phosphate binders exemplify the opportunity for using iron for both traditional (anemia) and novel (hyperphosphatemia) indications. Further optimization of iron therapy in patients with CKD may inform new approaches to the treatment of CKD complications and potentially allow modification of disease progression.

Antibody responses to inactivated SARS-CoV-2 vaccine in peritoneal dialysis patients

INTRODUCTION

As end-stage renal disease (ESRD) patients generally have reduced responses to the vaccines, effectiveness of newly developed SARS-CoV-2 vaccines in ESRD are also matters of curiosity. We aimed to investigate the humoral responses of our peritoneal dialysis (PD) patients to the inactivated SARS-CoV-2 vaccine.

METHODS

Humoral immune responses of 23 PD patients who received two doses of the inactivated SARS-CoV-2 vaccine were investigated with a commercial test that measures IgG antibodies towards receptor binding domain of SARS-CoV-2 spike protein. Seropositivity rates, antibody titers, and ESRD related clinical data were compared with 51 hemodialysis (HD) patients and 29 healthy volunteers.

RESULTS

Seropositivity of PD patients with the inactivated vaccine was 95.6%. Both the rate of seropositivity and SARS-CoV-2 IgG antibody levels in PD patients were not different from the healthy controls (p = 0.85 and 0.19, respectively). While seropositivity rates were not different for PD or HD patients (p = 0.09), the magnitude of humoral responses was significantly higher in PD patients (p = 0.0001). There were no vaccine-related serious adverse events. In the 3-months clinical follow-up, none of the patients experienced SARS-CoV-2 infection.

CONCLUSION

Two doses of the inactivated vaccine generate adequate humoral immune response in PD patients without any serious adverse events.

The Humoral Immune Response to BNT162b2 Vaccine Is Associated With Circulating CD19+ B Lymphocytes and the Naïve CD45RA to Memory CD45RO CD4+ T Helper Cells Ratio in Hemodialysis Patients and Kidney Transplant Recipients

Background

The humoral and cellular immune responses to SARS-COV-2 vaccination remain to be elucidated in hemodialysis (HD) patients and kidney transplant recipients (KTRs), considering their baseline immunosuppressed status. The aim of our study was to assess the associations of vaccine-induced antibody responses with circulating lymphocytes sub-populations and their respective patterns of alterations in maintenance HD patients and KTRs.

Materials and Methods

We included 34 HD patients and 54 KTRs who received two doses of the mRNA-vaccine BNT162b2. Lymphocyte subpopulations were analyzed by flow cytometry before vaccination (T0), before the second vaccine dose (T1) and 2 weeks after the second dose (T2). The anti-SARS-CoV2 antibody response was assessed at T1 and at T2.

Results

31 HD patients (91.8%) and 16 KTRs (29.6%) became seropositive at T2. HD patients who became seropositive following the first dose displayed higher CD19+ B lymphocytes compared to their seronegative HD counterparts. A positive correlation was established between CD19+ B cells counts and antibody titers at all time-points in both groups (p < 0.001). KTRs showed higher naïve CD4+CD45RA+ T helper cells compared to HD patients at baseline and T2 whereas HD patients displayed higher memory CD45RO+ T cells compared to KTRs at T2. The naïve CD4+CD45RA to memory CD4+CD45RO+ T helper cells fraction was negatively associated with antibody production in both groups.

Conclusions

Our study provides a potential conceptual framework for monitoring vaccination efficacy in HD patients and KTRs considering the correlation established between CD19+ B cells, generation of memory CD4+ T helper cells and anti SARS-CoV2 antibody response to vaccination.

End-Stage Renal Disease-Related Accelerated Immune Senescence: Is Rejuvenation of the Immune System a Therapeutic Goal?

End-stage renal disease (ESRD) patients exhibit clinical features of premature ageing, including frailty, cardiovascular disease, and muscle wasting. Accelerated ageing also concerns the immune system. Patients with ESRD have both immune senescence and chronic inflammation that are resumed in the so-called inflammaging syndrome. Immune senescence is particularly characterised by premature loss of thymic function that is associated with hyporesponsiveness to vaccines, susceptibility to infections, and death. ESRD-related chronic inflammation has multiple causes and participates to accelerated cardiovascular disease. Although, both characterisation of immune senescence and its consequences are relatively well-known, mechanisms are more uncertain. However, prevention of immune senescence/inflammation or/and rejuvenation of the immune system are major goal to ameliorate clinical outcomes of ESRD patients.

Comparison of Humoral and Cellular CMV Immunity in Patients Awaiting Kidney Transplantation

Chronic kidney disease may alter antiviral T cell immunity. In the current study, we assessed in 63 patients prior to kidney transplantation how humoral and cellular immunity against cytomegalovirus (CMV) correlated using an interferon (IFN)-γ ELISpot (T-Track^® CMV, Mikrogen, Neuried, Germany). The cohort comprised 24 patients with negative and 39 with positive CMV IgG. Whereas none of the patients with negative CMV IgG showed detectable responses to the T-Track^® CMV, 26 out of 39 patients with positive CMV IgG had positive ELISpot responses. The median response to CMV pp65 in the CMV seronegative group was 0 spot forming units (SFU) per 200,000 PBMC (range 0–1) and in the seropositive group 43 SFU (range 0–750). Thus, 13 out of 39 patients with positive CMV serostatus (33%) had undetectable T cell immunity and may be at an increased risk of CMV reactivation. CMV pp65-specific ELISpot responses were 29.3-fold higher in seropositive patients with vs. without dialysis and 5.6-fold higher in patients with vs. without immunosuppressive therapy, but patients with dialysis and immunosuppressive therapy showed, as expected, lower responses to phytohemagglutinin, the positive control. This finding may be caused by (subclinical) CMV-DNAemia and a “booster” of CMV-specific T cells.

Oxidative Stress in Patients with Advanced CKD and Renal Replacement Therapy: The Key Role of Peripheral Blood Leukocytes

Oxidative stress plays a key role in the pathophysiology of chronic kidney disease (CKD). Most studies have investigated peripheral redox state focus on plasma, but not in different immune cells. Our study analyzed several redox state markers in plasma and isolated peripheral polymorphonuclear (PMNs) and mononuclear (MNs) leukocytes from advanced-CKD patients, also evaluating differences of hemodialysis (HD) and peritoneal dialysis (PD) procedures. Antioxidant (superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), reduced glutathione (GSH)) and oxidant parameters (xanthine oxidase (XO), oxidized glutathione (GSSG), malondialdehyde (MDA)) were assessed in plasma, PMNs and MNs from non-dialysis-dependent-CKD (NDD-CKD), HD and PD patients and healthy controls. Increased oxidative stress and damage were observed in plasma, PMNs and MNs from NDD-CKD, HD and PD patients (increased XO, GSSG and MDA; decreased SOD, CAT, GPX and GSH; altered GSSG/GSH balance). Several oxidative alterations were more exacerbated in PMNs, whereas others were only observed in MNs. Dialysis procedures had a positive effect on preserving the GSSG/GSH balance in PMNs. Interestingly, PD patients showed greater oxidative stress than HD patients, especially in MNs. The assessment of redox state parameters in PMNs and MNs could have potential use as biomarkers of the CKD progression.

Hemodialysis acutely altered interferon-gamma release assay test result and immune cell profile

Patients receiving hemodialysis (HD) are at risk of TB development. IGRA-positive patients showed significant decrease in quantitative IGRA result with alterations in CD3⁺CD4⁺CD45RO⁺, NK cell, and monocyte subsets immediately upon HD procedure. Our result suggested that the timing of IGRA testing is crucial in end-stage renal disease population.

Differences between exhausted CD8+ T cells in hepatocellular carcinoma patients with and without uremia

The purpose of this study was to explore the differences between exhausted CD8+ T cells in hepatocellular carcinoma (HCC) patients with and without uremia. We enrolled 45 uremic patients who were recently diagnosed with HCC into the HCC + uremia cohort and similar patients with HCC but without uremia into the HCC-only cohort. Lymphocytes were obtained from the two cohorts, and exhausted CD8+ T cells, comprising PD-1+CD8+, TIM-3+CD8+, and LAG-3+CD8+ T cells, were sorted and expanded in vitro. After expansion, the proportions of PD-1+CD8+, TIM-3+CD8+, and LAG-3+CD8+ T cells were significantly higher in the HCC-only cohort than in the HCC + uremia cohort. CD8+ T cells expressing PD-1, TIM-3, or LAG-3 showed increased tumor reactivity and release of interferon-γ in vitro; however, these cells demonstrated weaker anti-tumor activity in HCC + uremia patients than in HCC-only patients. Among the expanded lymphocytes, only the decreased proportion of PD-1+CD8+ T cells significantly correlated with the HCC + uremia cohort (odds ratio of 2.731, p = 0.009). We concluded that peripheral CD8+ T cells expressing PD-1, TIM-3, or LAG-3 from the HCC + uremia cohort were dysfunctional in vitro. Among these populations, PD-1+CD8+ T cells were most evident in HCC patients with uremia.

Completion and Adverse Drug Events of Latent Tuberculosis Infection Treatment in Patients Receiving Dialysis: Predictors and Impacts of Different Regimens in a Prospective Cohort Study

Although patients with end-stage renal disease receiving maintenance hemodialysis are at high risk for tuberculosis, the optimal treatment regimen for latent tuberculosis infection (LTBI) in this group has scarcely been studied for predictors of completion rate and adverse drug events (ADE). We prospectively enrolled dialysis patients for LTBI intervention from three medical centers in Taiwan. LTBI treatments were 3 months of weekly rifapentine plus isoniazid (3HP) and 9 months of daily isoniazid (9H). Completion rate, ADE, and reasons for treatment termination were recorded. Factors associated with treatment termination and ADE were analyzed using multivariate logistic regression. In all, 91 treatment courses (41 9H and 50 3HP) were surveyed. The completion rates were 61% for 9H and 82% for 3HP (P = 0.046). Use of 9H and development of ADE with a grade of ≥2 (≥grade 2 ADE) were associated with treatment termination. Hypersensitivity occurred in 29.2% of subjects in the 3HP group and 10.8% in the 9H group (P = 0.035) and independently correlated with 3HP regimen, diabetes mellitus (DM), and peritoneal dialysis (PD). Similarly, the independent predictors of ≥grade 2 ADE were use of 3HP regimen, presence of DM, and use of PD, whereas ≥grade 3 ADE were associated with eosinophil counts of >700/mm³ after 2 weeks of LTBI treatment even after adjustment for age and gender. In conclusion, for patients on dialysis, 3HP showed a higher rate of completion but also a higher rate of ≥grade 2 ADE than 9H. In addition, DM and PD were risk factors for ≥grade 2 ADE. Eosinophilia after 2-week treatment might be an alert for severe ADE.

T cell markers recount the course of immunosenescence in healthy individuals and chronic kidney disease

Aging results in substantial changes in almost all cellular subpopulations within the immune system, including functional and phenotypic alterations. T lymphocytes, as the main representative population of cellular immunity, have been extensively studied in terms of modifications and adjustments during aging. Phenotypic alterations are attributed to three main mechanisms; a reduction of naïve T cell population with a shift to more differentiated forms, a subsequent oligoclonal expansion of naïve T cells characterized by repertoire restriction, and replicative insufficiency after repetitive activation. These changes and the subsequent phenotypic disorders are comprised in the term "immunosenescence". Similar changes seem to occur in chronic kidney disease, with T cells of young patients resembling those of healthy older individuals. A broad range of surface markers can be utilized to identify immunosenescent T cells. In this review, we will discuss the most important senescence markers and their potential connection with impaired renal function.

Association between renal failure and red blood cell alloimmunization among newly transfused patients

BACKGROUND

Renal failure and renal replacement therapy (RRT) affect the immune system and could therefore modulate red blood cell (RBC) alloimmunization after transfusion.

STUDY DESIGN AND METHODS

We performed a nationwide multicenter case-control study within a source population of newly transfused patients between 2005 and 2015. Using conditional multivariate logistic regression, we compared first-time transfusion-induced RBC alloantibody formers (N = 505) with two nonalloimmunized recipients with similar transfusion burden (N = 1010).

RESULTS

Renal failure was observed in 17% of the control and 13% of the case patients. A total of 41% of the control patients and 34% of case patients underwent acute RRT. Renal failure without RRT was associated with lower alloimmunization risks after blood transfusion (moderate renal failure: adjusted relative rate [RR], 0.82 [95% confidence interval (CI), 0.67-1.01]); severe renal failure, adjusted RR, 0.76 [95% CI, 0.55-1.05]). With severe renal failure patients mainly receiving RRT, the lowest alloimmunization risk was found in particularly these patients [adjusted RR 0.48 (95% CI 0.39-0.58)]. This was similar for patients receiving RRT for acute or chronic renal failure (adjusted RR, 0.59 [95% CI, 0.46-0.75]); and adjusted RR, 0.62 [95% CI 0.45-0.88], respectively).

CONCLUSION

These findings are indicative of a weakened humoral response in acute as well as chronic renal failure, which appeared to be most pronounced when treated with RRT. Future research should focus on how renal failure and RRT mechanistically modulate RBC alloimmunization.

Comparison of Psychological Distress and Demand Induced by COVID-19 during the Lockdown Period in Patients Undergoing Peritoneal Dialysis and Hemodialysis: A Cross-Section Study in a Tertiary Hospital

Background

Since the outbreak of COVID-19 in December 2019, it has spread rapidly and widely, bringing great psychological pressure to the public. In order to prevent the epidemic, traffic lockdown was required in many areas of China, which led to inconvenience of treatment for dialysis patients. This study was conducted to explore the psychological distress and the psychological demand induced by CO­VID-19 in the patients undergoing dialysis and compare the difference between hemodialysis (HD) and peritoneal dialysis (PD) patients during the traffic lockdown period.

Methods

Questionnaires were given to the dialysis patients in the West China Hospital of Sichuan University. The Impact of Event Scale (IES) was used to investigate the patients' trauma-related distress in response to COVID-19.

Results

232 eligible respondents were enrolled in this cross-section study, consisting of 156 PD patients and 76 HD patients. The median IES score for all the enrolled patients was 8.00 (2.00–19.00), which belonged to the subclinical dimension of post-traumatic stress symptoms (PTSS). HD patients had a significant higher IES score than PD patients (11.50 vs. 8.00) (p < 0.05). HD patients already got more psychological support from the medical staff. According to IES scores, 22.4% HD patients and 13.4% PD patients were classified as having moderate or severe PTSS, which need psychological support (p < 0.05). But more patients of both groups considered psychological support was necessary (HD: 50%, PD: 45.5%) (p > 0.05). In the multivariate regression analysis, we found that dialysis vintage, the impact of COVID-19 on the severity of illness and daily life, and confidence in overcoming the disease contributed to IES score (p < 0.05).

Conclusions

HD patients had more severe trauma-related stress symptoms than PD patients. When major public healthy events occurred, careful psychological estimate and sufficient psychological support should be provided to the dialysis patients, especially to the HD patients.

Influence of end stage renal disease on CD28 expression and T-cell immunity

BACKGROUND

T-cell immunity is affected in end stage renal disease (ESRD). However, whether this happens at pre- or post-dialysis stage and what is the impact of different renal replacement methods, remains unclear. We investigated the alterations of T-cell subtypes in patients at pre-dialysis ESRD and their further changes during dialysis.

METHODS

CD4+, CD8+, CD4 + CD28null and CD8 + CD28null T-cells were analysed in 40 ESRD patients at two different time points, (a) the day started on dialysis (ESRD-T0) and (b) 6 months later (ESRD-T6), while being on haemodialysis (HD) or continuous ambulatory peritoneal dialysis (CAPD). Twenty-five age matched healthy volunteers served as controls.

RESULTS

CD4+ and CD8+ T-cells were significantly reduced in ESRD-T0 patients compared to controls, 604 (105-3551) vs 943 (584-1867)μ/L, P = .001, and 352 (103-1561) vs 422.4 (263-1453)μ/L, P = .05, respectively. However, proportions of CD4 + CD28null and CD8 + CD28null cells were significantly increased, 6.4 (0.3-30)% vs 2.7 (0.1-7.8)%, P = .04 and 58.2 (12.8-85.4)% vs 39 (7.8-57.1)%, P = .01, respectively. Proportion of CD4 + CD28null cells showed significant correlation with serum CRP (r = .4, P = .04) and albumin levels (r = -.5, P = .007) in ERSD patients. ESRD-T0 patients with cardiovascular disease (CVD) had increased CD4 + CD28null and CD8 + CD28null proportions, 8.6 (1-30)% vs 2.1 (0.1-19.8)%, P = .04 and 62.5 (12.8-85.4)% vs 45.5 (5.7-73.7)%, P = .02, respectively, compared to those without. Six months later, both CD4 + CD28null and CD8 + CD28null T-cells were increased in HD compared to CAPD patients, by +110.11 (-27.1 to 311.4)% vs -28.1 (-100 to 30)%, P = .003 and +55.23 (-29.06 to 197.93)% vs -8.34 (-54.99 to 66.72)%, P = .05, respectively.

CONCLUSIONS

CD4 + CD28null and CD8 + CD28null T-cells are increased at pre-dialysis ESRD, and correlate with chronic inflammatory markers and the presence of CVD. Dialysis methods seem to have different impact on these subpopulations.

Premature aging of circulating T cells predicts all-cause mortality in hemodialysis patients

Background

Patients with end-stage renal disease (ESRD) exhibit a premature aging phenotype of immune system, which is recently concerned as a significant factor for increased risk of various morbidities. Nevertheless, there are few dates explicating the relevancy of T cell senescence to mortality. In this study, we prospectively studied the predictive value of T cell senescence for mortality in hemodialysis patients.

Methods

Patients who had been on hemodialysis treatment for at least 6 months were enrolled. T cell senescence determined by differentiation status was evaluated by flow cytometry. Survival outcomes were estimated using the Kaplan-Meier method. Univariate and multivariate analyses were performed to evaluate the prognostic impact of T cell premature aging and other clinical factors on all-cause mortality.

Results

A total of 466 patients (277 man and 169 women) were enrolled in this study. Decreased number of naïve T cell, as the most prominent feature of T cell senescence, did not change in parallel with age in these patients. Decreased absolute count of T cell, naïve T cell, CD4⁺ naïve T cell were independently associated with all-cause mortality. Decreased percentage of T cell and increased percentage of CD8⁺central-memory T cell were also independently associated with all-cause mortality. After including all the T cell parameters in one regression model, only decreased count of naïve T cell was significantly associated with increased mortality in these patients.

Conclusions

Aging-associated T cell changes are aggravated in ESRD patients. For the first time, our study demonstrates that naïve T cell depletion is a strong predictor of all-cause mortality in HD patients.

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.

Tuberculosis among Patients Undergoing Solid Organ Transplantation or Dialysis in a Low-Endemic Country, 2004-2017

Background

The risk of active TB among solid organ transplant (SOT) recipients and patients initiating chronic dialysis in a country with low incidence of TB is not well elucidated.

Methods

Patients aged >18 years who were transplanted with a solid organ or initiated chronic dialysis at Copenhagen University Hospital in the period 2004-2017 were followed from date of transplantation or initiation of dialysis. Data on demographics and outcomes were obtained from nationwide registries.

Results

We included 1,989 SOT recipients and 1,305 patients initiating chronic dialysis, who were followed for a total of 9,785 and 4,196 person-years (PY), respectively. Only a minority of patients had been screened for latent TB prior to SOT or initiation of dialysis. The incidence rates (IRs)/100,000 PY of TB among patients from medium/high TB endemic areas were 358 (95% CI 115-1,110) and 1,266 (95% CI 681-2354) for SOT and dialysis patients, respectively, whereas IRs among patients of Danish origin were 11 (95% CI 2-81) and 31 (95% CI 4-218).

Conclusion

The incidence of TB among immunosuppressed immigrants from medium/high TB endemic countries was very high, while the risk of TB among patients from low-endemic countries was minimal.

Immune response to influenza vaccination in ESRD patients undergoing hemodialysis vs. hemodiafiltration

BACKGROUND

On-line hemodiafiltration (HDF) clears more azotemic toxins compared to high-flux hemodialysis (HD). The response to vaccination is impaired in dialysis patients. We wished to determine whether the immune responses to influenza vaccine in dialysis patients treated by HDF were stronger than those treated by HD.

MATERIALS AND METHODS

We conducted a prospective cohort study in chronic dialysis patients during the 2016 and 2017 influenza seasons. All participants received a single standard dose of trivalent influenza vaccine, and we studied the elicited humoral immune response by hemagglutination inhibition test, and cell-mediated immune response by enumeration of lymphocyte cellular markers and proliferation assays.

RESULTS

We immunized 60 end-stage renal disease (ESRD) patients: 42 (70%) treated with HD and 18 patients (30%) with HDF. The median (interquartile range) age was 65.0 (55.0-74.5) years. All patients developed seroprotection to at least one influenza vaccine strain at one month post-vaccination, and did not differ between groups. By logistic regression, age was the only factor independently associated with seroconversion to all vaccine strains (odds ratio 0.89, 95% confidence interval 0.80-0.98; p = 0.022). Seroprotection to all vaccine strains was sustained for longer in patients treated with HDF, and the results remained the same after age adjustment. For cellular immune response, patients who seroconverted to all vaccine strains had higher CD38+ T cell subpopulations pre-vaccination. Patients treated by HDF had higher lymphocyte proliferation to circulating influenza A strains.

CONCLUSIONS

Seroconversion to all influenza vaccine strains was associated with age. Patients treated with HDF demonstrated seroprotection was sustained for longer compared to those treated by HD and greater lymphocyte proliferation to circulating influenza A strains. These encouraging results for HDF require confirmation in a larger dialysis population.

TRIAL REGISTRATION

ClinicalTrial.gov, NCT04122222.

Transplantation of Marginal Organs: Immunological Aspects and Therapeutic Perspectives in Kidney Transplantation

Recent data from the World Population Prospects projects that, by 2050, nearly all regions in the world will have a quarter or more of the population aged 60 and above. Chronic kidney disease (CKD) has a high global prevalence (~13%) worldwide, and the prevalence of chronic kidney disease and end-stage kidney disease increase with age. Kidney transplantation remains the best therapeutic option for end-stage kidney disease, offering a survival benefit in comparison with dialysis maintenance for most patients. This review focuses on immunological aspects of kidney transplantation in older patients and marginal donors, i.e., 60 years or older deceased kidney donors or 50–59 years old deceased kidney donors with comorbidities. Clinical outcomes of kidney recipients in terms of renal and patient survival are more than acceptable even for patients over 70. In this population, the first cause of graft loss is death with a functional graft. However, the inherent issues of these transplantations are the acceptance or refusal of frail kidney from an old donor and the increased immunogenicity of these organs in balance with potential frail and immunosenescent recipients. Finally, the immunosuppressive regimen itself is a challenge for the future of the transplant, to prevent adverse effects such as nephrotoxicity and higher risk of infections or cancer in a population already at risk. Belatacept may have a good place in the immunosuppressive strategy to improve efficacy and the safety posttransplantation.

[Premature immune senescence and chronic kidney disease: Update and perspectives]

Immune senescence is associated with age-related diseases (i.e. infectious disease, cardiovascular diseases and cancers). Chronic kidney disease patients die prematurely when compared with general population, because of a higher occurrence of infections, cardiovascular events and cancer. These diseases are commonly observed in the elderly population and frequently associated with immune senescence. Indeed, chronic kidney disease causes a premature aging of the T lymphocyte compartment, widely related to a decrease in thymic function, a phenomenon that plays a key role in the onset of age-related diseases in chronic kidney disease patients. The degree of immune senescence also influences patients' outcome after renal transplantation, particularly the risk of acute rejection and infections. Partial reversion of pre-transplant immune senescence is observed for some renal transplant patients. In conclusion, to reduce the increasing incidence of morbidity and mortality of chronic kidney disease patients, a better knowledge of uremia-induced immune senescence would help to pave the way to build clinical studies and promote innovative therapeutic approaches. We believe that therapeutic reversion and immune senescence prevention approaches will be part of the management of chronic kidney disease patients in the future.

Chronic Hepatitis C Infection Has No Effect on Peripheral CD4+CD25+ Tregulatory Cells in Patients with End-Stage Renal Disease

Background: T regulatory cells (Tregs), through variable mechanisms, play a crucial role in Hepatitis C virus (HCV) chronicity and infection tolerance. A great speculation is posed regarding the level, role of Tregs in end-stage renal disease (ESRD), and the presence of associated factors that could influence the Tregs population. Accordingly, we aimed at studying the effect of HCV infection on peripheral CD4⁺CD25⁺Tregs population among patients on hemodialysis (HD) as well as the effect of other comorbidities on these cells.Patients and methods: A group of 77 patients on HD (32 were HD HCV⁺ and 45 were HD HCV^-) and 80 healthy controls (HCs) were included in the study. Flow cytometric analysis was performed for identification and quantification of peripheral CD4⁺ CD25⁺Tregs.Results: The frequency of CD4⁺ CD25⁺Tregs increased significantly in HD patients compared to the HCs (p = <.0001 each). HCV posed no effect on peripheral CD4+ CD25+ Tregs in ESRD patients, when comparing HD HCV- and HD HCV+ groups. In the hypertensive HD HCV-, Tregs percentage was higher than that in the non-hypertensive. However, the difference was not statistically significant. No significant difference was detected between HD HCV- and HD HCV+ patients on the count and percentages of Tregs according to the duration of dialysis.Conclusion: Demonstrating that chronic HCV infection has no effect on CD4+ CD25+ Tregs cells levels in ESRD patients is of great importance to the success of future allografts in such patients.

End-Stage Renal Disease-Associated Gut Bacterial Translocation: Evolution and Impact on Chronic Inflammation and Acute Rejection After Renal Transplantation

Chronic inflammation in end-stage renal disease (ESRD) is partly attributed to gut bacterial translocation (GBT) due to loss of intestinal epithelium integrity. Increased levels of circulating lipopolysaccharide (LPS) –a surrogate marker of GBT– contribute to maintain a chronic inflammatory state. However, circulating LPS can be neutralized by lipoproteins and transported to the liver for elimination. While ESRD-associated GBT has been widely described, less is known about its changes and impact on clinical outcome after kidney transplantation (KT). One hundred and forty-six renal transplant recipients with serum samples obtained immediately before and 1 year after transplantation (1-Year post KT) were included. Intestinal epithelium integrity (iFABP), total LPS (by measuring 3-hydroxymyristate), LPS activity (biologically active LPS measured by the LAL assay), inflammatory biomarkers (sCD14 and cytokines), lipoproteins and LPS-binding proteins (LBP and phospholipid transfer protein [PLTP] activity) were simultaneously measured. At 1-Year post KT, iFABP decreased but remained higher than in normal volunteers. Total LPS concentration remained stable while LPS activity decreased. Inflammation biomarkers decreased 1-Year post KT. We concomitantly observed an increase in lipoproteins. Higher sCD14 levels before transplantation was associated with lower incidence of acute rejection. Although GBT remained stable after KT, the contemporary increase in lipoproteins could bind circulating LPS and contribute concomitantly to neutralization of LPS activity, as well as improvement in ESRD-associated chronic inflammation. Chronic exposure to LPS in ESRD could promote endotoxin tolerance and explain why patients with higher pre-transplant sCD14 are less prompt to develop acute rejection after transplantation.

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.

T-cell aging in end-stage renal disease: an evolving story with CMV

Established evidence from the last decade has suggested that chronic cytomegalovirus infection has strong impact on the human immune system, resulting in aggravated aging-associated T-cell changes that are associated with poorer vaccination responses, cardiovascular disease and shortened survival. Patients with end-stage renal disease (ESRD), the most severe form of chronic kidney disease, exhibit premature aging phenotypes in almost all organ systems, including the immune system. Longitudinal studies of T-cell aging in healthy humans have been scanty because it requires a large number of study subjects and a study duration for decades. In recent years, it became clear that ESRD patients with cytomegalovirus (CMV) infection exhibit enhanced aging-related immune changes than CMV-seropositive individuals without renal disease, including chronic inflammation, decreased numbers of naïve CD4+ and CD8+ T cells, increased clonality of memory T cells with skewed repertoire and shortened telomeres. These findings lead to the hypothesis that the uremic milieu and treatment for renal failure can lead to premature aging of T cells independent from CMV infection and suggest that ESRD can be an important disease model for studying human aging. Future studies deciphering the underlying mechanisms of accelerated T cell aging in ESRD patients may eventually reveal additional insights into T-cell persistence and function during aging in CMV-seropositive, non-ESRD individuals.

A comprehensive characterization of aggravated aging-related changes in T lymphocytes and monocytes in end-stage renal disease: the iESRD study

Background

Patients with end-stage renal disease (ESRD) exhibit a premature aging phenotype of the immune system. Nevertheless, the etiology and impact of these changes in ESRD patients remain unknown.

Results

Compared to healthy individuals, ESRD patients exhibit accelerated immunosenescence in both T cell and monocyte compartments, characterized by a dramatic reduction in naïve CD4+ and CD8+ T cell numbers but increase in CD8+ T_EMRA cell and proinflammatory monocyte numbers. Notably, within ESRD patients, aging-related immune changes positively correlated not only with increasing age but also with longer dialysis vintage. In multivariable-adjusted logistic regression models, the combination of high terminally differentiated CD8+ T cell level and high intermediate monocyte level, as a composite predictive immunophenotype, was independently associated with prevalent coronary artery disease as well as cardiovascular disease, after adjustment for age, sex, systemic inflammation and presence of diabetes. Levels of terminally differentiated CD8+ T cells also positively correlated with the level of uremic toxin p-cresyl sulfate.

Conclusions

Aging-associated adaptive and innate immune changes are aggravated in ESRD and are associated with cardiovascular diseases. For the first time, our study demonstrates the potential link between immunosenescence in ESRD and duration of exposure to the uremic milieu.

Electronic supplementary material

The online version of this article (10.1186/s12979-018-0131-x) contains supplementary material, which is available to authorized users.