Effect of Lymphocyte Phenotypic Alterations on the Humoral Response to Vaccination Against SARS-COV-2 in Dialysis Patients.

Background: The response to vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) varies depending on comorbidities. This study evaluated the clinical and immunological factors affecting the humoral response of patients with end-stage renal disease (ESRD) to the BNT162b2 vaccine. Methods: Humoral immunity was evaluated in 54 ESRD patients using serum levels of anti-receptor-binding domain (RBD) and neutralizing antibodies (NAbs), measured by a chemiluminescent immunoassay 30 (T1), 60 (T2), and 120 (T3) days after the second vaccine dose. The results were correlated to baseline patient T- and B-lymphocyte subpopulations determined by flow cytometry. Results: The proportion of seroconverted patients based on the NAb titer decreased from 83.3% at T1 to 53.7% at T3. Age was negatively correlated to the NAb titer at T1 and T2. Patients receiving hemodiafiltration had higher NAb titers at T3. Diabetes was associated with a lower response rate at T3. Univariate analysis revealed a positive correlation between the naïve CD4 T-lymphocyte population and RBD titer at T1 and the NAb titer at T3, with no association observed with naïve CD8 T lymphocytes. NAb titers at T3 were significantly correlated with late-differentiated CD4 T lymphocytes and terminally differentiated effector memory cells re-expressing CD45RA (TEMRA) CD8 T lymphocytes. RBD levels were positively correlated with naïve and memory B-lymphocyte counts at T3. Conclusions: Age, diabetes, and hemodialysis prescription had significant impacts on the response to vaccination. T- and B-lymphocyte phenotypes are major determinants of the humoral response potency to SARS-CoV-2 vaccination with BNT162b2 in patients with ESRD.

Hemodialysis Effects on Autonomic Function: Results of Linear and Nonlinear Analysis of Heart Rate Variability at Rest and in Response to Physical and Mental Stress Tests.

INTRODUCTION: Cardiac arrhythmias are the most common cause of death in hemodialysis. Autonomic dysfunction plays a central role in this arrhythmogenic background. Previous studies on hemodialysis-related changes in heart rate variability (HRV) give contradictory results. This study investigated HRV indices both at rest and in response to physical and mental stimulation maneuvers at multiple time-points around and during the hemodialysis procedure. METHODS: Autonomic function was assessed by linear and nonlinear HRV indices at predialysis, during dialysis (3 equal time-periods), postdialysis, and on the nondialysis day in 36 hemodialysis patients. Continuous measurement of beat-by-beat heart rate was recorded with Finometer-PRO (The Netherlands) at rest and after orthostatic, sit-to-stand, handgrip, and mental-arithmetic test. RESULTS: The RMSSD, SD1, and SD2 indices significantly increased during dialysis (early-HD, mid-HD, late-HD periods) compared with the predialysis levels (p < 0.05) and returned to baseline postdialysis (RMSSD: 54.39 ± 83.73 vs. 137.98 ± 109.53* vs. 119.85 ± 97.34* vs. 144.47 ± 88.74* vs. 85.82 ± 121.43msec, *p < 0.05 vs. predialysis and postdialysis). No differences were detected in the above indices between the predialysis and nondialysis day. However, postdialysis, the HRV responses to orthostatic and sit-to-stand tests were more exaggerated than in the predialysis measurements (p < 0.05). The HRV responses both at resting and physical tests in the nondialysis day were similar to the predialysis levels. HRV indices in the mental arithmetic test during hemodialysis were much higher than at the nondialysis day (RMSSD: 77.05 [180.41] versus 19.75 [105.47] msec; p = 0.031). CONCLUSIONS: Hemodialysis causes marked changes in the autonomic function. Resting HRV indices return to baseline postdialysis, but HRV responses to physical stress remain exaggerated and return to baseline on the nondialysis day. Detecting patients with significant autonomic dysfunction may help towards reduction of arrhythmia risk through individualized approaches.

Two Cases of Autoimmune Thyroid Disorders after COVID Vaccination in Dialysis Patients.

SARS-CoV-2 infection and vaccination have been associated with autoimmune thyroid dysfunctions. Autoimmune/inflammatory syndrome induced by adjuvants (ASIA) and molecular mimicry have been referred to as potential causes. Such a case has not been reported in immunocompromised end-stage renal disease (ESRD) patients. Herein we present two dialysis patients with no previous history of thyroid disease who developed immune mediated thyroid disorders after BNT162b mRNA vaccine against SARS-CoV-2. The first patient is a 29-year-old man on hemodialysis diagnosed with Grave's disease four months post-vaccination and the second one is a 67-year-old female on peritoneal dialysis who developed Hashimoto's thyroiditis two months post-vaccination. Grave's disease is uncommon in dialysis patients, whereas Hashimoto's thyroiditis has a higher incidence in this population. Time proximity in both cases suggests potential causality. To our knowledge, this is the first report of de novo immune-mediated thyroid disorders in dialysis patients following vaccination against SARS-CoV-2.

Clustering of End Stage Renal Disease Patients by Dimensionality Reduction Algorithms According to Lymphocyte Senescence Markers.

End stage renal disease (ESRD) engenders detrimental effects in the Immune system, manifested as quantitative alterations of lymphocyte subpopulations, akin, albeit not identical to those observed during the ageing process. We performed dimensionality reduction of an extended lymphocyte phenotype panel of senescent and exhaustion related markers in ESRD patients and controls with Principal Component Analysis (PCA) and Uniform Manifold Approximation and Projection (UMAP). The plane defined by the first two principal components of PCA showed two fuzzy clusters, for patients and controls, respectively, with loadings of non-senescent markers pointing towards the controls' centroid. Naive lymphocytes were reduced in ESRD patients compared to controls (CD4+CD45RA+CCR7+ 200(150-328) vs. 426(260-585cells/µl respectively, P = 0.001, CD19+IgD+CD27- 54(26-85) vs. 130(83-262)cells/µl respectively, P < 0.001). PCA projections of the multidimensional ESRD immune phenotype suggested a more senescent phenotype in hemodialysis compared to hemodiafiltration treated patients. Lastly, clustering based on UMAP revealed three distinct patient groups, exhibiting gradual changes for naive, senescent, and exhausted lymphocyte markers. Machine learning algorithms can distinguish ESRD patients from controls, based on their immune-phenotypes and also, unveil distinct immunological groups within patients' cohort, determined possibly by dialysis prescription.

Association of peridialytic, intradialytic, scheduled interdialytic and ambulatory BP recordings with cardiovascular events in hemodialysis patients.

BACKGROUND: Ambulatory-BP-monitoring (ABPM) is recommended for hypertension diagnosis and management in hemodialysis patients due to its strong association with outcomes. Intradialytic and scheduled interdialytic BP recordings show agreement with ambulatory BP. This study assesses in parallel the association of pre-dialysis, intradialytic, scheduled interdialytic and ambulatory BP recordings with cardiovascular events. METHODS: We prospectively followed 242 hemodialysis patients with valid 48-h ABPMs for a median of 45.7 months to examine the association of pre-dialysis, intradialytic, intradialytic plus pre/post-dialysis readings, scheduled interdialytic BP, and 44-h ambulatory BP with outcomes. The primary end-point was a composite one, composed of cardiovascular death, non-fatal myocardial infarction, non-fatal stroke, resuscitation after cardiac arrest, hospitalization for heart failure, coronary revascularization procedure or peripheral revascularization procedure. RESULTS: Cumulative freedom from the primary end-point was significantly lower with increasing 44-h SBP (group 1, < 120 mmHg, 64.2%; group 2, ≥ 120 to < 130 mmHg 60.4%, group 3, ≥ 130 to < 140 mmHg 45.3%; group 4, ≥ 140 mmHg 45.5%; logrank-p = 0.016). Similar were the results for intradialytic (logrank-p = 0.039), intradialytic plus pre/post-dialysis (logrank-p = 0.044), and scheduled interdialytic SBP (logrank-p = 0.030), but not for pre-dialysis SBP (logrank-p = 0.570). Considering group 1 as the reference group, the hazard ratios of the primary end-point showed a gradual increase with higher BP levels with all BP metrics, except pre-dialysis SBP. This pattern was confirmed in adjusted analyses. An inverse association of DBP levels with outcomes was shown with all BP metrics, which was no longer evident in adjusted analyses. CONCLUSIONS: Averaged intradialytic and scheduled home BP measurements (but not pre-dialysis readings) display similar prognostic associations with 44-h ambulatory BP in hemodialysis patients and represent valid metrics for hypertension management in these individuals.

Ambulatory blood pressure changes with lung ultrasound-guided dry-weight reduction in hypertensive hemodialysis patients: 12-month results of a randomized controlled trial.

OBJECTIVES: Hypertension is highly prevalent and independently associated with adverse outcomes in patients undergoing hemodialysis. Volume overload is the main mechanism of increased blood pressure (BP) in these individuals. This study examines the long-term effects of dry-weight reduction with a standardized lung-ultrasound (US)-guided strategy on ambulatory BP in hypertensive hemodialysis patients. METHODS: This is the report of the 12-month follow-up of a randomized controlled trial in 71 clinically euvolemic, hemodialysis patients with hypertension. Patients were randomized to dry-weight reduction guided by prehemodialysis lung ultrasound and to standard care. A 48-h ambulatory BP monitoring (ABPM) was performed in all study participants at baseline and after 12 months. RESULTS: During follow-up, a greater proportion of patients in the active group underwent dry-weight reduction compared with the control group (71.4% vs. 22.2%; P < 0.001). The number of lung US-B lines (a metric of lung water) reduced in the active (-4.83 ±â€Š13.73) and increased in the control arm (+5.53 ±â€Š16.01; P = 0.005) paralleling dry-weight changes (-1.68 ±â€Š2.38 vs. 0.54 ±â€Š2.32 kg; P < 0.001). At 12 months, 48-h systolic BP (136.19 ±â€Š14.78 vs. 130.31 ±â€Š13.57 mmHg; P = 0.034) and diastolic BP (80.72 ±â€Š9.83 vs. 76.82 ±â€Š8.97 mmHg; P = 0.008) were lower compared to baseline in the active but similar in the control group. Changes in 48-h systolic BP (-7.78 ±â€Š13.29 vs. -0.10 ±â€Š14.75 mmHg; P = 0.021) were significantly greater in the active compared to the control group. The proportion of patients experiencing ≥1 episode of intradialytic hypotension was nominally lower in the active group (71.4% vs. 88.9%, P = 0.065). CONCLUSIONS: Lung-US-guided dry-weight reduction can effectively and safely decrease ambulatory BP levels in the long-term.

TNF-α pathway and T-cell immunity are activated early during the development of diabetic nephropathy in Type II Diabetes Mellitus.

Aim of the present study was to investigate the possible involvement of TNF-α signaling pathway and T-lymphocyte activation in DN. Eighty-two diabetic patients [39 male, age 69.5(56-78)years] were divided into three groups, according to Albumin/Creatinine ratio (ACR) levels, Group I (ACR < 30 µg/mg), Group II (ACR 30-300 µg/mg), Group III (ACR > 300 µg/mg). Urinary Tumor Necrosis Factor-α (TNF-α), and serum TNF-α, ΤNF-receptor 1 (TNFR1), TNFR2, B7-1, CD28, Cytoxic T-Lymphocyte-Associated protein-4 (CTLA4), were estimated. There were significant differences between Groups I, II, III regarding the concentration of urinary TNF-α (p < .001), serum TNFR1 (p < .001), serum TNFR2(p < .001), CTLA4 (p < .001) and CD28(p = .034). In multivariate analysis, independent parameters correlated with ACR were serum TNFR1 (p = .003), TNFR2 (p = .012) and urinary TNF-α (p = .015) levels. There was a significant correlation between markers of T-cell activation and TNF-α signaling pathway activation. Activation of TNF-α signaling pathway and T-lymphocytes seem to synergize and participate in the development of DN in type II DM.

Chronic Therapy with Sucroferric Oxyhydroxide Does Not Affect Iron and Anemia Markers in Dialysis Patients.

INTRODUCTION: Sucroferric oxyhydroxide (SOH) is an iron-based phosphate binder (PB), and its use has been widely expanded since its initial approval in 2014. Based on the existing data, however, it remains yet unclear whether its long-term administration is followed by iron overload in dialysis patients. The purpose of this observational study was to evaluate the longstanding effects of SOH on the anemia and iron indices in patients on dialysis. METHODS: A total of 110 patients from 3 dialysis centers were included in the study; 49 were under chronic treatment with SOH (cohort A), while 61 were either receiving other PB or no treatment for hyperphosphatemia (cohort B). We initially compared the hematologic profile of patients in 2 cohorts (phase I), and subsequently, we evaluated modifications of the above parameters in the SOH treated patients over a period of 6 months (phase II). RESULTS: There were no statistically significant differences between 2 cohorts in terms of hemoglobin (Hb; 11.4 ± 1.3 vs. 11.6 ± 0.9 g/dL, p = 0.375), ferritin (473 ± 230 vs. 436 ± 235 ng/mL, p = 0.419) and transferrin saturation (TSAT;26.6 ± 13.2 vs. 26.5 ± 10.6%, p = 0.675), serum phosphate concentration (4.57 ± 1.05 vs. 4.3 ± 0.96 mg/dL, p = ns), and intact PTH (286 ± 313 vs. 239 ± 296 pg/mL, p = ns). Marginally, but significantly higher calcium levels were found in cohort A compared to cohort B (9.18 ± 0.58 vs. 8.9 ± 0.51 mg/dL, respectively, p = 0.008). In phase II, no significant changes were observed in hematological parameters after a 6-month treatment with SOH (Hb: from 11.5 ± 1.1 to 11.4 ± 1.3 g/dL, p = 0.4, serum ferritin levels: from 475 ± 264 to 473 ± 230 ng/mL, p = 0.951, TSAT: from 26.5 ± 16.7 to 26.6 ± 13.2%, p = 0.933). There were also no significant changes in the administration of iron supplements or erythropoietin dose during this period. CONCLUSIONS: SOH is an effective PB, and its long-term use is not complicated by iron overload.

Lung Ultrasound-Guided Dry Weight Assessment and Echocardiographic Measures in Hypertensive Hemodialysis Patients: A Randomized Controlled Study.

RATIONALE & OBJECTIVE: Left ventricular (LV) hypertrophy and dysfunction are associated with adverse outcomes in hemodialysis patients. Hypertension and hypervolemia play important roles in these cardiac abnormalities. We report on the prespecified secondary outcome, echocardiographic indexes of LV function, from a previously reported study of the effect of lung ultrasound (US)-guided dry weight reduction on systolic blood pressure. STUDY DESIGN: Single-blind randomized trial. SETTINGS & PARTICIPANTS: 71 clinically euvolemic hypertensive hemodialysis patients in Greece and Slovenia. INTERVENTION: The active intervention group's (n=35) volume removal was guided by the total number of lung US B-lines observed every week before a midweek dialysis session. The usual-care group (n=36) was treated using standard-of-care processes that did not include acquisition of US data. OUTCOMES: 2-dimensional and tissue Doppler echocardiographic indexes at baseline and study end (8 weeks) that evaluated left and right heart chamber sizes, as well as systolic and diastolic function. RESULTS: Overall, 19 (54%) patients in the active intervention and 5 (14%) in the usual-care group had ultrafiltration intensification (P<0.001) during follow-up; changes in US B-lines (-5.3±12.5 vs+2.2±7.6; P<0.001) and dry weight (-0.71±1.39 vs+0.51±0.98kg; P<0.001) significantly differed between the active and usual-care groups. Inferior vena cava diameter decreased in the active compared with the usual-care group (-0.43±4.00 vs 0.71±4.82cm; P=0.03) at study end. Left (LA) and right (RA) atrial dimensions decreased more in the active group (LA surface, -1.09±4.61 vs 0.93±3.06cm2; P=0.03; RA surface -1.56±6.17 vs 0.47±2.31; P=0.02). LA volume index nominally decreased more in the active group (-2.43±13.14 vs 2.95±9.42mL/m2), though this was of borderline statistical significance (P=0.05). Reductions in LV end-diastolic diameter and volume were marginally greater in the active group. The change in LV filling pressures was significantly different in the active compared with the usual-care group (early transmitral diastolic velocities ratio [E/e'], -0.38±3.14 vs 1.36±3.54; P=0.03; E wave deceleration time, 35.43±85.25 vs-18.44±50.69; P=0.002]. Systolic function indexes were unchanged in both groups. In multivariable analysis, US B-line reduction was associated with a reduction in the E/e' LV ratio (OR, 4.542; 95% CI, 1.266-16.292; P=0.02). LIMITATIONS: Exploratory study; small sample size. CONCLUSIONS: A US-guided strategy for dry weight reduction is associated with decreased cardiac chamber dimensions and LV filling pressure, but no difference in systolic performance compared with usual care in hypertensive hemodialysis patients. FUNDING: European Renal Association-European Dialysis and Transplant Association. TRIAL REGISTRATION: Registered at ClinicalTrials.gov with study number NCT03058874.

Beneficial effect of atorvastatin on erythropoietin responsiveness in maintenance haemodialysis patients.

AIM: To evaluate the effect of atorvastatin on erythropoietin responsiveness and whether this effect is mediated by C-reactive protein (CRP) reduction in prevalent dyslipidemic, haemodialysis patients. METHODS: We studied prospectively 33 stable, iron-repleted haemodialysis patients with low-density lipoprotein cholesterol (LDL) > or =2.58 mmol/L, who received 20 mg atorvastatin aiming to achieve the target of LDL <2.58 mmol/L, over a period of 9 months. Twenty-five patients completed the study, 15 men, with mean age 66.1 +/- 8.2 years. The duration of haemodialysis was 56.6 +/- 63.1 months and 5/25 patients were diabetics. Total serum cholesterol, triglycerides, high-density lipoprotein cholesterol, LDL, haemoglobin, albumin, intact parathyroid hormone, serum iron, ferritin, total iron binding capacity, CRP and weekly dose of erythropoietin/body weight/haemoglobin were analysed. RESULTS: Twenty of the 25 patients (80%) achieved the goal of LDL <2.58 mmol/L. There was a significant decrease in total cholesterol (5.77 +/- 0.88 to 4.16 +/- 0.96 mmol/L, P < 0.001) and LDL (3.59 +/- 0.77 to 1.94 +/- 0.77 mmol/L, P < 0.001). Haemoglobin increased from 121 +/- 11 to 126 +/- 7 g/L (P < 0.05), while weekly dose of erythropoietin/body weight/haemoglobin decreased significantly from 8.34 +/- 3.70 to 7.87 +/- 3.11 IU/kg per haemoglobin (P < 0.05). CRP decreased not significantly from 7.0 +/- 6.1 to 4.5 +/- 2.2 mg/L. CONCLUSION: Dyslipidemia of haemodialysis patients was treated safely and effectively with atorvastatin, but a fifth of the patients failed to achieve the therapeutic target. Statin therapy resulted in a significant increase of haemoglobin levels and improvement of erythropoietin responsiveness without a significant reduction in CRP levels, suggesting that the beneficial effect of statins on erythropoietin responsiveness may be driven by a mechanism other than CRP reduction.

Effect of iron loading on peripheral blood lymphocyte subsets and on circulating cytokine levels in iron-depleted hemodialysis patients receiving erythropoietin.

BACKGROUND/AIMS: High doses of iron are recommended intravenously in iron-depleted hemodialysis (HD) patients receiving recombinant erythropoietin (EPO). Iron deficiency and mainly iron overload impair cellular and humoral immune response mechanisms. Imbalances in T cell subsets are common findings in disorders of iron metabolism. The aim of this study was to evaluate the effect of iron load on peripheral blood lymphocytes subsets and on circulating cytokine levels in HD iron depleted patients, treated with EPO. METHODS: We studied 19 stable adult HD patients, 12 males, with a mean age 59 +/- 11 years and mean HD duration 24 +/- 14 months. All patients were iron deficient and were treated with unchanged EPO dose for the last 4 months before entering the study. The administered dose of iron was infused intravenously (1,000 mg iron sucrose) in 10 doses, during 10 consecutive HD sessions. Patients were screened before the commencement of the HD session on two occasions, once prior to the first dose of iron and 2 days after the 10th dose. Hematocrit (Ht), hemoglobin (Hb), iron, serum ferritin, transferrin saturation, interleukin (IL)-2, IL-4, IL-10, interferon-gamma and tumor necrosis factor-alpha were measured. Major lymphocyte subsets (CD3+, CD19+, CD4+, CD8+, CD16+/56+, CD3+CD16+CD56+) and the ratio CD4+/CD8+ were also determined by two-color immunofluorescent analysis using flow cytometry. RESULTS: Hb, transferrin saturation and ferritin increased significantly at the end of the study 11.2 +/- 0.9 to 11.6 +/- 0.8 g/dl, p < 0.005, 17.5 +/- 6.9 to 23.0 +/- 10.8 %, p < 0.05, and 70 +/- 43 to 349 +/- 194 microg/l, p < 0.005, respectively. IL-2 also increased significantly 27.8 +/- 15.2 to 38.9 +/- 12.8 pg/ml, p < 0.05. After iron load there was no significant change to the major lymphocyte subsets examined but a significant increase of the percentage and number of T lymphocytes with positive natural killer receptors (NKR+ T) cells was observed, 5.1 +/- 3.7% to 6.3 +/- 3.46%, p < 0.05, and 76.4 +/- 40 to 101.5 +/- 48 cells/microl, p < 0.005, respectively. CONCLUSION: Iron load in iron-deficient EPO-treated HD patients did not produce any changes in major lymphocyte subsets in peripheral blood, but it resulted in a significant increase of NKR+ T cells, a subpopulation important for local immune responses. Iron load for a relatively short period improved anemia of HD patients and influenced the levels of the circulating IL-2, which may regulate factors affecting the survival of patients.

Erythropoietin attenuates renal injury in experimental acute renal failure ischaemic/reperfusion model.

BACKGROUND: Erythropoietin (EPO), originally identified for its critical role in promoting erythrocyte survival and differentiation, has been shown to exert multiple paracrine/autocrine functions. Protective effects of EPO have been demonstrated in various tissues and experimental models of ischaemia-induced injury. In the present study, we investigated the effect of EPO on an in vivo rat model of renal ischaemia/reperfusion (I/R) injury and the possible mechanisms implicated in the EPO-mediated anti-apoptotic action. METHODS: Male Wistar rats, subjected to renal ischaemia for 45 min, were administered either saline or EPO (500 U/kg, i.p.) 20 min prior to I/R. A sham-operated group served as the control. At 48 h of reperfusion, the renal dysfunction and injury was assessed by measurement of serum biochemical markers (urea, creatinine) and histological grading. Apoptosis was assessed by the TUNEL method and morphological criteria. Expression of Bax and NF-kappaB (p65) was also evaluated. RESULTS: High levels of serum urea and creatinine were identified at 48 h after ischaemia. The EPO-treated group had significantly lower serum and creatinine levels. Semi-quantitative assessment of the histological lesions showed that rats subjected to I/R developed marked structural damage, whereas significantly less tubular damage was observed in the EPO-treated group. I/R caused an increase in TUNEL-positive cells that was accompanied by morphological evidence of apoptosis. In the EPO-treated rats only a few scattered TUNEL-positive cells were observed. Up-regulation of Bax in the tubular epithelial cells and increased expression of NF-kappaB was observed in the I/R-treated rats, while diminished expression of Bax and positive immunostaining of NF-kappaB was observed in the EPO-treated rats. CONCLUSION: Administration of EPO as a single dose before the onset of ischaemia produced a significant reduction in tubular injury, which was accompanied by a marked amelioration of renal functional impairment. The cytoprotective action of EPO against I/R injury seems to be associated with its anti-apoptotic action. Moreover, transcription factor NF-kappaB is likely to play a pivotal role in the pathophysiology of I/R renal injury and might have a key role in EPO-mediated protective effects.