Dysfunction of natural killer cells in end-stage kidney disease on hemodialysis

Association between elevated serum soluble B7-H6 and infection in hemodialysis patients

BACKGROUND

Infection represents the second most common factor causing death in uremia, partly owing to immune dysfunction. Soluble B7-H6, a soluble form of cell-surface immunoreceptor B7-H6, is induced under infectious conditions. So far, the levels of circulating soluble B7-H6 in uremia cases have not been examined.

METHODS

In this prospective cohort study, 55 patients undergoing maintenance hemodialysis were recruited from October 2021 to February 2022; 20 healthy volunteers were enrolled.

INTERVENTION(S)

None. All hemodialysis cases were followed up until death, switched to peritoneal dialysis, transplantation, or confirmed infection.

RESULTS

Patients were followed up for a mean duration of 331 days. Sixteen hemodialysis cases were diagnosed with infectious diseases, including pneumonia in seven cases, urinary tract infection in four, shingles in two, cutaneous infection in two, and sepsis in one. Compared with healthy controls, serum soluble B7-H6 amounts were markedly elevated in hemodialysis cases with or without infection (P < 0.001). Soluble B7-H6 levels were markedly increased in hemodialysis cases with infection compared to counterparts without infection (P < 0.001). Multivariable Cox proportional hazards model showed that soluble B7-H6 was the significant predictor of infection in hemodialysis patients (hazard ratio 3.308; 95% confidence interval 1.118-9.794; P = 0.031). Patients with high-serum soluble B7-H6 levels had a markedly higher cumulative hazard rate of infection in comparison with the low-serum soluble B7-H6 group (P < 0.05). Finally, soluble B7-H6 levels were positively correlated with neutrophil count (P < 0.05).

CONCLUSIONS

This study first showed that serum soluble B7-H6 is elevated in hemodialysis patients and could be considered a potential predictive factor of infection under such conditions.

Network Pharmacology and Experimental Analysis to Explore the Effect and Mechanism of Modified Buyang Huanwu Decoction in the Treatment of Diabetic Nephropathy

Purpose

Preventing and treating diabetic nephropathy (DN) are global challenges due to the complexity and diversity of its causes and manifestations. It is important to find effective medications to treat DN.

Patients and Methods

Gene expression files of DN were downloaded from the GEO database to identify the differentially expressed genes. Network pharmacology and molecular docking were used to explore the possible mechanisms of modified Buyang Huanwu Decoction (mBHD) in treating DN. Biochemical, histopathological, and real-time PCR analyses were conducted in both in vivo and in vitro DN models to investigate the effects of mBHD.

Results

A total of 336 active ingredients and 124 potential targets of mBHD associated with DN were identified. Among them, 8 hub genes were found to be important targets for mBHD in treating DN and were significantly correlated with the infiltration status of six immune cells. Partially, the active ingredients of mBHD demonstrated good stability in binding to CASP3 and TP53. mBHD treatment significantly reduced levels of total cholesterol, triglyceride, blood urea nitrogen, serum creatinine, and microalbumin in db/db mice. HE and Masson's staining results showed that mBHD attenuated renal injury in db/db mice. Additionally, mBHD treatment could significantly alter the expression of CASP3, CCL2, TP53, ALB, and HMOX1.

Conclusion

mBHD may be involved in the treatment of DN through multiple ingredients, targets, and pathways. In addition, mBHD could alleviate renal injury in db/db mice, possibly involving CASP3, CCL2, TP53, ALB, and HMOX1.

Kidney Transplantation and Cellular Immunity Dynamics: Immune Cell Alterations and Association with Clinical and Laboratory Parameters

Background/Objectives: The purpose of this study was to evaluate numerical changes in immune cells after successful kidney transplantation and associate their recovery with clinical and laboratory factors. Methods: In 112 kidney transplant recipients, we performed flow cytometry to evaluate counts of CD4+, CD8+, and regulatory T cells (Tregs), as well as natural killer (NK) cells, before kidney transplantation (T0) and three (T3), six (T6), and twelve (T12) months later. The results were associated with the recipient's age, cold ischemia time (CIT), the type of donor, dialysis method and vintage, and graft function in one year. Results: Total and CD8+ T cell counts increased gradually one year post transplantation in comparison with pre-transplantation levels, whereas the number of CD4+ T cells and Tregs increased, and the number of NK cells decreased in the first three months and remained stable thereafter. The recipient's age was negatively correlated with total, CD4+, and Treg counts at T12, whereas CIT affected only total and CD4+ T cell count. Moreover, recipients receiving kidneys from living donors presented better recovery of all T cell subsets at T12 in comparison with recipients receiving kidneys from cadaveric donors. Patients on peritoneal dialysis had increased numbers of total and CD8+ T cells, as well as NK cells. Finally, estimated glomerular filtration rate was positively correlated with Treg level and potentially CD4+ T cells one-year post transplantation. Conclusions: Successful kidney transplantation results in the recovery of most T cell subsets. Lower recipient age and better graft function contribute to increased T cell counts, whereas donor type and dialysis modality are the most important modifiable factors for optimal immune recovery.

Altered transcriptomic immune responses of maintenance hemodialysis patients to the COVID-19 mRNA vaccine

Background

End-stage renal disease (ESRD) patients experience immune compromise characterized by complex alterations of both innate and adaptive immunity, and results in higher susceptibility to infection and lower response to vaccination. This immune compromise, coupled with greater risk of exposure to infectious disease at hemodialysis (HD) centers, underscores the need for examination of the immune response to the COVID-19 mRNA-based vaccines.

Methods

The immune response to the COVID-19 BNT162b2 mRNA vaccine was assessed in 20 HD patients and cohort-matched controls. RNA sequencing of peripheral blood mononuclear cells was performed longitudinally before and after each vaccination dose for a total of six time points per subject. Anti-spike antibody levels were quantified prior to the first vaccination dose (V1D0) and 7 d after the second dose (V2D7) using anti-spike IgG titers and antibody neutralization assays. Anti-spike IgG titers were additionally quantified 6 mo after initial vaccination. Clinical history and lab values in HD patients were obtained to identify predictors of vaccination response.

Results

Transcriptomic analyses demonstrated differing time courses of immune responses, with prolonged myeloid cell activity in HD at 1 wk after the first vaccination dose. HD also demonstrated decreased metabolic activity and decreased antigen presentation compared to controls after the second vaccination dose. Anti-spike IgG titers and neutralizing function were substantially elevated in both controls and HD at V2D7, with a small but significant reduction in titers in HD groups (p<0.05). Anti-spike IgG remained elevated above baseline at 6 mo in both subject groups. Anti-spike IgG titers at V2D7 were highly predictive of 6-month titer levels. Transcriptomic biomarkers after the second vaccination dose and clinical biomarkers including ferritin levels were found to be predictive of antibody development.

Conclusions

Overall, we demonstrate differing time courses of immune responses to the BTN162b2 mRNA COVID-19 vaccination in maintenance HD subjects comparable to healthy controls and identify transcriptomic and clinical predictors of anti-spike IgG titers in HD. Analyzing vaccination as an in vivo perturbation, our results warrant further characterization of the immune dysregulation of ESRD.

Funding

F30HD102093, F30HL151182, T32HL144909, R01HL138628. This research has been funded by the University of Illinois at Chicago Center for Clinical and Translational Science (CCTS) award UL1TR002003.

Preoperative chronic kidney disease and complications after pancreatoduodenectomy: a retrospective cohort study

BACKGROUND

Chronic kidney disease is a prevalent condition in surgical patients. Possible associations with increased postoperative morbidity and mortality have not been clearly demonstrated in patients undergoing pancreatoduodenectomy. The aim of this study was to assess the risk of postoperative complications in patients with reduced kidney function undergoing pancreatoduodenectomy.

METHODS

All patients undergoing pancreatoduodenectomy at Karolinska University Hospital between 2008 and 2019 were retrospectively included. The variable of interest was chronic kidney disease, based on preoperative estimated glomerular filtration rate measurements. Unadjusted and adjusted logistic regression analyses were performed for standardized postoperative complications.

RESULTS

A total of 971 patients were included in the study, of whom 92 (10%) had an estimated glomerular filtration rate < 60 mL/min/1.73m2 , equivalent to chronic kidney disease Stage 3a or worse. Patients with chronic kidney disease had a higher odds of longer hospital stay (adjusted odds ratio 1.58, 95% confidence interval 1.00-2.50) and postoperative weight increase (adjusted odds ratio 2.02, 1.14-3.56). A 10 unit increase of preoperative estimated glomerular filtration rate was associated to lower odds of intensive care unit admission (adjusted odds ratio 0.81, 0.69-0.95), delayed gastric emptying (adjusted odds ratio 0.90, 0.81-0.99), and post-operative pancreatic fistula (adjusted odds ratio 0.83, 0.74-0.94).

CONCLUSION

Patients undergoing pancreatoduodenectomy with decreased preoperative kidney function are more likely to experience major postoperative complications, and also postoperative weight increase. Preoperative kidney function assessment is important in risk stratification before pancreatoduodenectomies.

Comparison of Diet, Sleep, and Stress During the Emergency Coronavirus Disease Curfew in Men and Women with Hemodialysis

OBJECTIVE

To investigate the effect of coronavirus disease 2019 (COVID-19) on diet, stress, and sleep in Japanese patients with hemodialysis.

METHODS

Data on nutritional intake, frequency of food intake by cuisine, dietary behavior, and frequency of food use before and during the declaration of the state of emergency due to COVID-19, were collected.

RESULTS

For the 81 participants (47 men), changes were observed in the following diet-related items: nutrition and nutrient content (one item for men, three for women), eating behavior, and frequency of food use (1 item for men, six for women), and the total number of items was two for men and nine for women. Nine out of 12 questions addressed stress and six out of eight questions addressed sleep, with a higher percentage of women adversely affected and no item with a higher percentage of men adversely affected. The mean score for stress was 25.3 ± 5.1 for men and 29.5 ± 5.0 for women, P < .001, and for sleep disturbance was 11.6 ± 3.0 for men and 14.4 ± 4.4 for women, P < .001.

CONCLUSIONS

In patients with hemodialysis, the effect of refraining from going out due to the spread of COVID-19 on diet, sleep, and stress was suggested to be more significant in women than in men.

Expression of Interferon Regulatory Factor 8 (IRF8) and Its Association with Infections in Dialysis Patients

Patients on dialysis have dysfunctions of innate and adaptive immune system responses. The transcriptional factor IRF8 (interferon regulatory factor 8) is primarily expressed in plasmacytoid cells (pDCs) and myeloid dendritic cells (mDCs), playing a crucial role in the maturation of dendritic cells, monocytes, and macrophages, and contributing to protection against bacterial infections. The current study analyzed the expression patterns of IRF8 and assessed its association with the risk of infections in 79 dialysis patients compared to 44 healthy controls. Different subsets of leukocytes and the intracellular expression of IRF8 were measured using flow cytometry. Compared to the healthy controls, the dialysis patients showed significantly reduced numbers of pDCs and significantly increased numbers of natural killer cells and classical and intermediate monocytes. The dialysis patients exhibited decreased numbers of IRF8-positive dendritic cells (pDC p < 0.001, mDC1 p < 0.001, mDC2 p = 0.005) and increased numbers of IRF8-positive monocytes (p < 0.001). IRF8 expression in pDC, mDC, and classical monocytes was lower in the dialysis patients than in the controls. Dialysis patients who required hospitalization due to infections within one year of follow-up displayed significantly reduced IRF8 expression levels in pDCs compared to patients without such infections (p = 0.04). Our results suggest that reduced IRF8 expression in pDCs is a potential risk factor predisposing dialysis patients to serious infections.

Dysregulated phosphate metabolism in autism spectrum disorder: associations and insights for future research

Studies of autism spectrum disorder (ASD) related to exposure to toxic levels of dietary phosphate are lacking. Phosphate toxicity from dysregulated phosphate metabolism can negatively impact almost every major organ system of the body, including the central nervous system. The present paper used a grounded theory-literature review method to synthesise associations of dysregulated phosphate metabolism with the aetiology of ASD. Cell signalling in autism has been linked to an altered balance between phosphoinositide kinases, which phosphorylate proteins, and the counteracting effect of phosphatases in neuronal membranes. Glial cell overgrowth in the developing ASD brain can lead to disturbances in neuro-circuitry, neuroinflammation and immune responses which are potentially related to excessive inorganic phosphate. The rise in ASD prevalence has been suggested to originate in changes to the gut microbiome from increasing consumption of additives in processed food, including phosphate additives. Ketogenic diets and dietary patterns that eliminate casein also reduce phosphate intake, which may account for many of the suggested benefits of these diets in children with ASD. Dysregulated phosphate metabolism is causatively linked to comorbid conditions associated with ASD such as cancer, tuberous sclerosis, mitochondrial dysfunction, diabetes, epilepsy, obesity, chronic kidney disease, tauopathy, cardiovascular disease and bone mineral disorders. Associations and proposals presented in this paper offer novel insights and directions for future research linking the aetiology of ASD with dysregulated phosphate metabolism and phosphate toxicity from excessive dietary phosphorus intake.

Immune response to the mRNA COVID-19 vaccine in hemodialysis patients: cohort study

Background

End-stage renal disease (ESRD) patients experience immune compromise characterized by complex alterations of both innate and adaptive immunity, and results in higher susceptibility to infection and lower response to vaccination. This immune compromise, coupled with greater risk of exposure to infectious disease at hemodialysis (HD) centers, underscores the need for examination of the immune response to the COVID-19 mRNA-based vaccines.

Methods

A transcriptomic analysis of the immune response to the Covid-19 BNT162b2 mRNA vaccine was assessed in 20 HD patients and cohort-matched controls. RNA sequencing of peripheral blood mononuclear cells (PBMCs) was performed longitudinally before and after each vaccination dose for a total of six time points per subject. Anti-spike antibody levels were quantified prior to the first vaccination dose (V1D0) and seven days after the second dose (V2D7) using anti-Spike IgG titers and antibody neutralization assays. Anti-spike IgG titers were additionally quantified six months after initial vaccination. Clinical history and lab values in HD patients were obtained to identify predictors of vaccination response.

Results

Transcriptomic analyses demonstrated differing time courses of immune responses, with predominant T cell activity in controls one week after the first vaccination dose, compared to predominant myeloid cell activity in HD at this time point. HD demonstrated decreased metabolic activity and decreased antigen presentation compared to controls after the second vaccination dose. Anti-spike IgG titers and neutralizing function were substantially elevated in both controls and HD at V2D7, with a small but significant reduction in titers in HD groups (p < 0.05). Anti-spike IgG remained elevated above baseline at six months in both subject groups. Anti-spike IgG titers at V2D7 were highly predictive of 6-month titer levels. Transcriptomic biomarkers after the second vaccination dose and clinical biomarkers including ferritin levels were found to be predictive of antibody development.

Conclusion

Overall, we demonstrate differing time courses of immune responses to the BTN162b2 mRNA COVID-19 vaccination in maintenance hemodialysis subjects (HD) comparable to healthy controls (HC) and identify transcriptomic and clinical predictors of anti-Spike IgG titers in HD. Analyzing vaccination as an in vivo perturbation, our results warrant further characterization of the immune dysregulation of end stage renal disease (ESRD).

Funding

F30HD102093, F30HL151182, T32HL144909, R01HL138628This research has been funded by the University of Illinois at Chicago Center for Clinical and Translational Science (CCTS) award UL1TR002003.

Levels of Soluble NKG2D Ligands and Cancer History in Patients Starting Hemodialysis

Background

Immune dysfunction in hemodialysis patients is partially due to NK cell impairment. Ligands for NK activating receptors such as NKG2D expressed on cancer cells are involved in NK cell dysfunction and can lead to cancer development.

Methods

A cohort with 370 patients who started hemodialysis (HD) was investigated. Serum levels of soluble NKG2D ligands were measured. Cancer history was defined as any cancer diagnosis at induction and hospitalization and death due to cancer during 2-year follow-up.

Results

Sixty-two patients with and 308 patients without a cancer history showed mostly comparable biochemical parameters and uremic status at HD induction. Soluble MICB, ULBP-1, and ULBP-2 were detected in sera from most patients starting HD rather than MICA, the most representative NKG2D ligand. Measured NKG2D ligands, except for ULBP-1, were strongly correlated with each other. Correlations between NKG2D ligands and renal function were significant but modest in patients starting HD. Cancer history did not have any impact on levels of soluble NKG2D ligands.

Discussion

Even though this investigation lacked a control cohort and serial measurement of parameters, expression patterns of NKG2D ligands were comprehensively described, and the significance of cancer in patients starting HD was elucidated for the first time. Elevated levels of soluble NKG2D ligands occurred potentially due to complex mechanisms of oxidative stress, with insufficient metabolism and excretion in a uremic milieu, but they might mask the significance of elevations in serum levels of soluble NKG2DLs in patients with a cancer history.

Secondary Immunodeficiency Related to Kidney Disease (SIDKD)-Definition, Unmet Need, and Mechanisms

Kidney disease is a known risk factor for poor outcomes of COVID-19 and many other serious infections. Conversely, infection is the second most common cause of death in patients with kidney disease. However, little is known about the underlying secondary immunodeficiency related to kidney disease (SIDKD). In contrast to cardiovascular disease related to kidney disease, which has triggered countless epidemiologic, clinical, and experimental research activities or interventional trials, investments in tracing, understanding, and therapeutically targeting SIDKD have been sparse. As a call for more awareness of SIDKD as an imminent unmet medical need that requires rigorous research activities at all levels, we review the epidemiology of SIDKD and the numerous aspects of the abnormal immunophenotype of patients with kidney disease. We propose a definition of SIDKD and discuss the pathogenic mechanisms of SIDKD known thus far, including more recent insights into the unexpected immunoregulatory roles of elevated levels of FGF23 and hyperuricemia and shifts in the secretome of the intestinal microbiota in kidney disease. As an ultimate goal, we should aim to develop therapeutics that can reduce mortality due to infections in patients with kidney disease by normalizing host defense to pathogens and immune responses to vaccines.