B lymphopenia in uremia is related to an accelerated in vitro apoptosis and dysregulation of Bcl-2

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

CD19+ B-Cells, a New Biomarker of Mortality in Hemodialysis Patients

Background and objectives

Mortality of patients on hemodialysis (HD) remains very high despite recent improvements in HD techniques. Cardiovascular (CV) complications and infections are the main causes of death. Some studies suggest that disturbances in the immune system could play a role in this disproportionate mortality, through the links of immunity with inflammation and propensity to infections. However, few studies have addressed the role of lymphocyte populations and the global and CV mortality of HD patients.

Aim

To analyze the relationship of peripheral blood lymphocyte populations (PBLP) and all-cause and CV mortality of HD patients.

Design, setting, participants, and measurements

We design a prospective observational single center study in a cohort of HD prevalent patients. PBLP were analyzed at baseline and after 1 year and patients were followed for a 5-year period. Main outcomes were all-cause and CV mortality.

Results

One hundred and four patients (51% male, mean age 64.8 ± 15 years) were included. Follow-up was 18 (7–47) months. Fifty-five patients (52.8%) died, main causes of death being CVD (40%) and infections (29.1%). Low total lymphocyte counts were found in 47 patients (45.2%), and the most frequency lymphopenias were CD19⁺ B-cell (57.7%), CD3⁺ (40.4%), and CD4⁺ (36.5%). After 1 year, all determinations were lower except CD56⁺CD16⁺CD3⁻ natural killer. Patient survival was significantly lower in patients with a CD19⁺ B-cell count < 100 cells/μL at baseline as compared to patients with CD19⁺ B-cell ≥ 100 cells/μL counts at the end of follow-up (16.5 vs 54%, p = 0.003). By multivariable analysis, age, history of CV disease, Charlson index, a KT/V < 1.2, and a CD19⁺ B-cell count < 100 cells/μL at baseline and after 1-year were factors associated with of all-cause mortality. A CD19⁺ B-cell count < 100 cells/μL at baseline was associated with CV mortality.

Conclusion

CD19⁺ B-cell lymphopenia is very common among HD patients, and it could be an independent predictor of all-cause and CV mortality. More studies are needed to confirm these findings.

p-Cresyl sulfate decreases peripheral B cells in mice with adenine-induced renal dysfunction

Infection is a major cause of mortality in chronic kidney disease (CKD) patients. Although immune dysfunction is a risk factor for infection in CKD patients, its causes are not fully elucidated. In the present study, we evaluated whether p-cresyl sulfate (pCS), an intestinal bacteria-derived uremic toxin, was involved in immune dysfunction in CKD. We used osmotic pumps to establish adenine-induced renal dysfunction mice with a chronically high blood pCS concentration. Analysis of lymphocyte subsets revealed that pCS significantly reduced peripheral B cells in renal dysfunction mice. In vitro, pCS inhibited interleukin (IL)-7-induced proliferation of CD43⁺ B-cell progenitors and suppressed IL-7-induced phosphorylation of signal transducer and activator of transcription 5 (STAT5) in these cells. Cell cycle analysis showed that pCS significantly decreased the percentage of CD43⁺ B-cell progenitors in S phase and increased that in G1 phase. These results suggest that pCS suppressed IL-7-induced STAT5 signaling and inhibited B-cell progenitor proliferation, leading to reduction of peripheral B cells in adenine-induced renal dysfunction mice. Therefore, pCS decreases peripheral B cells by inhibiting proliferation of CD43⁺ B-cell progenitors and is a likely cause of immune dysfunction in CKD patients.

Aoike D, Q. Redublo BM, C. Batista M, Cendoroglo M, Maria Moyses R, Dalboni MA. Cholecalciferol decreases inflammation and improves vitamin D regulatory enzymes in lymphocytes in the uremic environment: A randomized controlled pilot trial

It has been reported that vitamin D regulates the immune system. However, whether vitamin D repletion modulates inflammatory responses in lymphocytes from dialysis patients is unclear. In the clinical trial, thirty-two (32) dialysis patients with 25 vitamin D ≤ 20ng/mL were randomized to receive either supplementation of cholecalciferol 100,000 UI/week/3 months (16 patients) or placebo (16 patients). In the in vitro study, B and T lymphocytes from 12 healthy volunteers (HV) were incubated with or without uremic serum in the presence or absence of 25 or 1,25 vitamin D. We evaluated the intracellular expression of IL-6, IFN-γ TLR7, TLR9, VDR, CYP27b1 and CYP24a1 by flow cytometry. We observed a reduction in the expression of TLR7, TLR9, INF-γ and CYP24a1 and an increase in VDR and CYP27b1 expression in patients which were supplemented with cholecalciferol, whereas no differences were found in the placebo group. Uremic serum increased the intracellular expression of IL-6, IFN-γ, TLR7, TLR9, VDR, CYP27b1 and CYP24a1. Treatment with 25 or 1,25 vitamin D decreased IL-6 and TLR9. CYP24a1 silencing plus treatment with 25 and/or 1,25 vitamin D had an additional reduction effect on IL-6, IFN-γ, TLR7 and TLR9 expression. This is the first study showing that cholecalciferol repletion has an anti-inflammatory effect and improves vitamin D intracellular regulatory enzymes on lymphocytes from dialysis patients.

Targeting Immunity in End-Stage Renal Disease

BACKGROUND

Despite the stable incidence of end-stage renal disease (ESRD), it continues to be associated with an unacceptably high cardiovascular risk.

SUMMARY

ESRD is characterized by enhanced oxidative stress and severe inflammation, which boost cardiovascular risk, thus increasing cardiovascular-associated mortality rate. While substantial effort has been made in the technological innovation of dialytic techniques, few significant advances have been made to reduce inflammation in patients with ESRD. Indeed, this contrasts with the extensive scientific breakthroughs made in the basic field of science in targeting inflammation. There is thus a pressing need for clinical trials to test the effect of reducing inflammation in patients with ESRD. Here, we will revisit the negative effect of ESRD on inflammation and explore the impact of enhanced inflammation on cardiovascular outcomes and survival in patients with ESRD. Finally, we will discuss the need for clinical trials that target inflammation in ESRD, as well as weigh potential disadvantages and offer novel innovative approaches. Key Message: We will try to understand why the issue of inflammation has not been successfully addressed thus far in patients with ESRD, while at the same time weighing the potential disadvantages and offering novel innovative approaches for targeting inflammation in patients with ESRD.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Risk of pneumonia among patients with chronic kidney disease in outpatient and inpatient settings: a nationwide population-based study

Patients with chronic kidney disease (CKD) are more at risk for pneumonia than the general population. Patients with pneumonia are usually treated as outpatients. However, previous studies were conducted on the basis of inpatient pneumonia. This method may underestimate the risk of pneumonia in patients with CKD. Therefore, we investigated the risk of pneumonia among CKD patients in both outpatient and inpatient settings. A total of 15,562 patients with CKD and 62,109 individuals without CKD (matched for age and gender) were taken as subjects in the Longitudinal Health Insurance Database of Taiwan National Insurance from 1996 to 2010. The incidence density rates of inpatient and outpatient pneumonia were calculated. The risk factors associated with pneumonia were analyzed using Cox proportional hazard models with adjustments for confounders. The incidence density rate of pneumonia was 65.6 per 1000 person-years in patients with CKD and 28.4 per 1000 person-years in individuals without CKD. The incidence density rate of inpatient pneumonia was 43.3 per 1000 person-years in patients with CKD and 16.6 per 1000 person-years in individuals without CKD. CKD was associated with increased risk of pneumonia (adjusted hazard ratio [aHR], 1.97; 95% confidence interval [CI], 1.89-2.05; P < 0.001), outpatient pneumonia (aHR, 1.40; 95% CI, 1.31-1.49), and inpatient pneumonia (aHR, 2.17; 95% CI, 2.07-2.29, P < 0.001). Patients' comorbidities, including diabetes, cardiovascular disease (CVD), asthma, and chronic obstructive pulmonary disease (COPD), were independently associated with increased risk of pneumonia.CKD is associated with the increased risk of both outpatient and inpatient pneumonia. This association is independent of comorbid diabetes, CVD, asthma, and COPD.

T-cell ageing in end-stage renal disease patients: Assessment and clinical relevance

End-stage renal disease (ESRD) patients have a defective T-cell-mediated immune system which is related to excessive premature ageing of the T-cell compartment. This is likely to be caused by the uremia-associated pro-inflammatory milieu, created by loss of renal function. Therefore, ESRD patients are highly susceptible for infections, have an increased risk for virus-associated cancers, respond poorly to vaccination and have an increased risk for atherosclerotic diseases. Three ageing parameters can be used to assess an immunological T-cell age. First, thymic output can be determined by assessing the T-cell receptor excision circles-content together with CD31 expression within the naïve T cells. Second, the telomere length of T cells and third the T-cell differentiation status are also indicators of T-cell ageing. Analyses based on these parameters in ESRD patients revealed that the immunological T-cell age is increased by on average 20 years compared to the chronological age. After kidney transplantation (KTx) the aged T-cell phenotype persists although the pro-inflammatory milieu is diminished. This might be explained by epigenetic modifications at hematopoietic stem cells level. Assessment of an immunological T-cell age could be an important tool to identify KTx recipients who are at risk for allograft rejection or to prevent over-immunosuppression.

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

BACKGROUND

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

AIM

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

SUBJECTS AND METHODS

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

RESULTS

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

CONCLUSION

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

Hematologic manifestations of kidney disease

Physiologically, there is an intimate link between the kidney and the blood. Many of the kidney diseases are the result of alteration in the blood such as dysproteinemia, microangiopathic hemolytic anemia (MAHA), hemolysis, etc. On the other hand, the kidney is the organ responsible for the regulation of hematopoiesis. Renal dysfunction can lead to both anemia and polycythemia. In addition, recent understanding of the MAHA process reveals that the renal microvasculature plays a key role in the pathogenesis. Finally, the failure of the kidney to clear toxins from the body can result in alteration involving hemostasis, as well as leukocyte function and survival.

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

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

Blastocystis and Schistosomiasis Coinfection in a Patient with Chronic Kidney Disease

Chronic kidney disease (CKD) and end-stage renal disease (ESRD) represent a spectrum of impaired immunity with effects on cellular immunity, soluble immune factors, and inflammation. As a result, infections due to impaired immune system responses are responsible for significant morbidity in patients with kidney disease. Because of immune dysfunction in CKD, these patients have reduced probability to clear infections and are susceptible to pathogenic effects of common organisms. We present a case of a patient with CKD coinfected with Schistosoma mansoni and Blastocystis spp. This appears to be the first reported association of Schistosoma mansoni and Blastocystis spp. in a patient with CKD.

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

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

Elevated pretransplantation soluble BAFF is associated with an increased risk of acute antibody-mediated rejection

BACKGROUND

B cells play an important role in renal allograft pathology, particularly in acute and chronic antibody-mediated rejection (AMR). B-cell activating factor belonging to the tumor necrosis factor family (BAFF; also known as BLyS) is a cytokine that enhances B-cell survival and proliferation.

METHODS

We analyzed serum BAFF levels in 32 patients undergoing antibody-incompatible (Ai) renal transplantation and 319 antibody-compatible transplant recipients and sought to determine whether there was a correlation with acute rejection and with transplant function and survival.

RESULTS

We demonstrate that, in patients undergoing Ai transplantation, elevated serum BAFF levels at baseline (before both antibody removal/desensitization and transplantation) are associated with an increased risk of subsequent AMR. In antibody-compatible transplant recipients at lower risk of AMR, no statistically significant association was observed between pretransplantation serum BAFF and AMR.

CONCLUSIONS

These data raise the possibility that, in high immunologic risk patients undergoing Ai transplantation, the presence of elevated pretransplantation serum BAFF might identify those at increased risk of AMR. BAFF neutralization may be an interesting therapeutic strategy to explore in these patients, particularly because such agents are available and have already been used in the treatment of autoimmunity.

Leukocyte proliferation and immune modulator production in patients with chronic kidney disease

INTRODUCTION

In Chronic Kidney Disease (CKD), immune cells are affected by uremic retention toxins. Given this effect, we analyzed lymphocyte proliferative response and immune modulators production following in vitro stimulation.

METHODS

Whole blood was drawn from healthy controls, patients with eGFR <20 ml/min/1.73 m(2) (Pre-dialysis, CKD stages 4 and 5) and hemodialysis patients (stage 5D). Peripheral cells were incubated for six days with pokeweed mitogen, concanavalin A, Staphylococcus enterotoxin A or influenza A vaccine. Peripheral lymphocyte proliferation was then analyzed by the "Flow-cytometric Assay of Specific Cell-mediated Immune response in Activated whole blood" (FASCIA) method, and cytokine profile in the cell supernatants was analyzed by the Milliplex multi-array method.

RESULTS

The absolute number of lymphoblasts in response to mitogenic stimulation and the number of cells in each CD4+ and CD8+ subpopulation were similar comparing the three groups, except for a single decline in number of lymphoblasts after stimulation with Staphylococcus enterotoxin A, comparing dialysis patients with healthy controls. Levels of interleukin (IL)-2 (p=0.026), -10 (p=0.019) and -15 (p=0.027) in the Staphylococcus enterotoxin A-stimulated supernatant were lower in hemodialysis patients compared to healthy controls. Levels of IL-15 (p=0.017) from pre-dialysis patients and levels of IL-5 (p=0.019) from hemodialysis patients in influenza A vaccine-stimulated supernatants were also lower compared to controls. In pokeweed mitogen-stimulated supernatant, IL-2 levels (p=0.013) were lower in hemodialysis patients compared to pre-dialysis patients. TNF-α, IL-10, IL-12, IL-15, IL-8, MCP-1, IP-10, IFN-α2, IL-1α and eotaxin levels were all significantly higher in plasma obtained from CKD patients.

CONCLUSION

Our results suggest that T-cells from CKD patients have similar proliferative response to stimulation compared with healthy individuals. Moreover, however the immune cells show inability to produce selected cytokines, most likely due to the uremic milieu or dialysis procedure.

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

Background

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

Methods

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

Results

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

Conclusions

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

Immune cell dysfunction and inflammation in end-stage renal disease

Uraemia causes inflammation and reduces immune system function as evidenced by an increased risk of viral-associated cancers, increased susceptibility to infections and decreased vaccination responses in patients with end-stage renal disease (ESRD). The substantially increased risk of atherosclerosis in these patients is also probably related to uraemia-associated inflammation. Uraemia is associated with a reduction in the number and function of lymphoid cells, whereas numbers of myeloid cells in uraemic patients are normal or increased with increased production of inflammatory cytokines and reactive oxygen species. Similar to healthy elderly individuals, patients with ESRD have increased numbers of specific proinflammatory subsets of T cells and monocytes, suggesting the presence of premature immunological ageing in these patients. These cells might contribute to inflammation and destabilization of atherosclerotic plaques, and have, therefore, been identified as novel nonclassical cardiovascular risk factors. The cellular composition of the immune system does not normalize after successful kidney transplantation despite a rapid reduction in inflammation and oxidative stress. This finding suggests that premature ageing of the immune system in patients with ESRD might be related to a permanent skewing of the haematopoetic stem cell population towards myeloid-generating subsets, similar to that seen in healthy elderly individuals.

B cell-associated immune profiles in patients with end-stage renal disease (ESRD)

Most of the previous studies on immune dysregulation in end-stage renal disease (ESRD) have focused on T cell immunity. We investigated B cell subpopulations in ESRD patients and the effect of hemodialysis (HD) on B cell-associated immune profiles in these patients. Forty-four ESRD [maintenance HD patients (n = 27) and pre-dialysis patients (n = 17)] and 27 healthy volunteers were included in this study. We determined the percentage of B cell subtypes, such as mature and immature B cells, memory B cells, and interleukin (IL)-10⁺ cells, as well as B cell-producing cytokines (IL-10, IL-4 and IL-21) by florescent activated cell sorting (FACS). B cell-associated gene expression was examined using real-time PCR and B cell producing cytokines (IL-10, IL-4 and IL-21) were determined using an enzyme-linked immunosorbent assay (ELISA). The percentage of total B cells and mature B cells did not differ significantly among the three groups. The percentages of memory B cells were significantly higher in the pre-dialysis group than in the HD group (P < 0.01), but the percentage of immature B cells was significantly lower in the pre-dialysis group than in the other groups. The percentages of IL-10-expressing cells that were CD19⁺ or immature B cells did not differ significantly (P > 0.05) between the two subgroups within the ESRD group, but the serum IL-10 concentration was significantly lower in the pre-dialysis group (P < 0.01). The results of this study demonstrate significantly altered B cell-associated immunity. Specifically, an imbalance of immature and memory B cells in ESRD patients was observed, with this finding predominating in pre-dialysis patients.

Mononuclear leukocyte apoptosis and inflammatory markers in patients with chronic kidney disease

BACKGROUND/AIM

Increased apoptosis along with enhanced inflammation has been reported in hemodialysis and pre-dialysis patients. However, there is limited information at which stage during the progression of chronic kidney disease (CKD) the balance between pro- and anti-apoptotic mechanisms is disturbed and inflammatory response is activated. The aim of this study was to investigate possible alterations in apoptotic and inflammatory markers during CKD (stages 1-4) progression and the probable interactions between them.

METHODS

In a cross-sectional study, 152 steady-state CKD outpatients (83 males, 55%) with mean estimated glomerular filtration rate 46 (29-76) ml/min/1.73 m(2) were studied. Apoptosis was assessed in peripheral blood mononuclear cells by estimating Bcl-2 expression, annexin V-propidium iodine staining and serum soluble Fas (sFas) and Fas-ligand. Serum levels of C-reactive protein, tumor necrosis factor-α (TNF-α), interleukin-6 and plasma levels of fibrinogen were measured as markers of inflammation.

RESULTS

Bcl-2 expression was found to decrease significantly in both lymphocytes and monocytes from CKD stage 1 to 4. In contrast, the activity of sFas increased significantly and so did the levels of TNF-α and fibrinogen. The majority of these alterations occurred as soon as patients entered stage 3 of CKD. A multivariate regression analysis demonstrated that CKD remained a significant predictor of the aggregate of the assessed markers.

CONCLUSIONS

Apoptosis appeared to increase across CKD stages 1-4, and this was associated with increased proinflammatory activity.

Influenza vaccine effectiveness in patients on hemodialysis: an analysis of a natural experiment

BACKGROUND

Although the influenza vaccine is recommended for patients with end-stage renal disease, little is known about its effectiveness. Observational studies of vaccine effectiveness (VE) are challenging because vaccinated subjects may be healthier than unvaccinated subjects.

METHODS

Using US Renal Data System data, we estimated VE for influenza-like illness, influenza/pneumonia hospitalization, and mortality in adult patients undergoing hemodialysis by using a natural experiment created by the year-to-year variation in the match of the influenza vaccine to the circulating virus. We compared vaccinated patients in matched years (1998, 1999, and 2001) with a mismatched year (1997) using Cox proportional hazards models. Ratios of hazard ratios compared vaccinated patients between 2 years and unvaccinated patients between 2 years. We calculated VE as 1 - effect measure.

RESULTS

Vaccination rates were less than 50% each year. Conventional analysis comparing vaccinated with unvaccinated patients produced average VE estimates of 13%, 16%, and 30% for influenza-like illness, influenza/pneumonia hospitalization, and mortality, respectively. When restricted to the preinfluenza period, results were even stronger, indicating bias. The pooled ratio of hazard ratios comparing matched seasons with a placebo season resulted in a VE of 0% (95% CI, -3% to 2%) for influenza-like illness, 2% (-2% to 5%) for hospitalization, and 0% (-3% to 3%) for death.

CONCLUSIONS

Relative to a mismatched year, we found little evidence of increased VE in subsequent well-matched years, suggesting that the current influenza vaccine strategy may have a smaller effect on morbidity and mortality in the end-stage renal disease population than previously thought. Alternate strategies (eg, high-dose vaccine, adjuvanted vaccine, and multiple doses) should be investigated.

Effect of uremia on structure and function of immune system

End-stage renal disease (ESRD) is simultaneously associated with immune activation, marked by systemic inflammation, and immune deficiency. Systemic inflammation contributes to atherosclerosis, cardiovascular disease, cachexia, and anemia, whereas immune deficiency leads to impaired response to vaccination, and increased incidence and severity of microbial infections. ESRD-associated inflammation and immune deficiency are associated with the following: (a) general expansion of monocytes and elevations of their basal integrin, Toll-like receptor (TLR)-2, TLR-4 expression, cytokine production, and reactive oxygen species (ROS) generation and reduced phagocytic capacity, (b) depletion and impaired inhibitory activity of regulatory T cells, (c) spontaneous activation, degranulation, increased basal ROS production, decreased phagocytic capacity, and increased apoptosis of the circulating polymorphonuclear leukocytes, (d) upregulation of ROS production machinery and chemokine expression in the cellular constituents of various tissues, highlighting participation of nonimmune cells in the prevailing inflammatory state, (e) depletion of the antigen-presenting dendritic cells, (f) reduced CD4/CD8 T cell ratio and depletion of naïve and central memory T cells, (g) diffuse B cell lymphopenia leading to impaired humoral immunity, and (h) increased proinflammatory activity of low-density lipoprotein and reduced anti-inflammatory capacity of high-density lipoprotein. Thus, ESRD-associated inflammation is due to activation of innate immune system, orchestrated by monocytes, macrophages, granulocytes, and cellular constituents of other organs/tissues. This is coupled with immune deficiency that is caused by depletion of dendritic cells, naïve and central memory T cells and B cells, and impaired phagocytic function of polymorphonuclear leukocytes and monocytes.

The low dose of rituximab in ABO-incompatible kidney transplantation without a splenectomy: a single-center experience

PURPOSE

A new protocol for ABO-incompatible (ABO-i) kidney transplantation including rituximab was introduced in January 2005 in our institute. This study reviewed the results and evaluated the use of low-dose rituximab in ABO-i kidney transplantation.

MATERIAL AND METHODS

Seventy-four de novo ABO-i kidney transplantations were performed at Tokyo Women's Medical University between January 2005 and August 2010. The immunosuppressive protocol was consisting of tacrolimus, mycophenolate mofetil, and methylprednisolone. All the patients received induction therapy with basiliximab. The pre-conditioning protocol included double-filtration plasmapheresis and a single dose of rituximab. A dose of 500 mg/body rituximab was initially employed and yielded excellent results (Group I, n = 24). Afterward, the dose of rituximab was reduced to 200 mg/body in January 2007 (Group II, n = 50).

RESULTS

Seventy-four de novo ABO-i recipients were treated with this protocol, and all patients underwent kidney transplantation successfully. Effective elimination of the peripheral blood CD19 cells was observed in both groups. However, the peripheral blood CD19 levels were still low in both groups at 24 months after treatment.

CONCLUSION

The patients in Group II showed excellent results similar to Group I. These results suggest that the low dose of rituximab (200 mg/body) is the sufficient dose in ABO-i kidney transplantation.

Prediction of influenza vaccination outcome by neural networks and logistic regression

The major challenge in influenza vaccination is to predict vaccine efficacy. The purpose of this study was to design a model to enable successful prediction of the outcome of influenza vaccination based on real historical medical data. A non-linear neural network approach was used, and its performance compared to logistic regression. The three neural network algorithms were tested: multilayer perceptron, radial basis and probabilistic in conjunction with parameter optimization and regularization techniques in order to create an influenza vaccination model that could be used for prediction purposes in the medical practice of primary health care physicians, where the vaccine is usually dispensed. The selection of input variables was based on a model of the vaccine strain which has frequently been changed and on which a poor influenza vaccine response is expected. The performance of models was measured by the average hit rate of negative and positive vaccine outcome. In order to test the generalization ability of the models, a 10-fold cross-validation procedure revealed that the model obtained by multilayer perceptron produced the highest average hit rate among neural network algorithms, and also outperformed the logistic regression model with regard to sensitivity and specificity. Sensitivity analysis was performed on the best model and the importance of input variables was discussed. Further research should focus on improving the performance of the model by combining neural networks with other intelligent methods in this field.

Different profiles of cytokine expression during mild and severe acute pancreatitis

AIM

To study secretion patterns of pro- and anti-inflammatory cytokines, and activation of various cellular subsets of leukocytes in peripheral blood.

METHODS

We have conducted a prospective observational study. One hundred and eight patients with a diagnosis of acute pancreatitis and onset of the disease within last 72 h were included in this study. The mRNA expression of 25 different types of cytokines in white blood cells was determined by quantitative real time polymerase chain reaction. Levels of 8 different cytokines in blood serum were measured by enzyme linked immunosorbent assay. Clinical data and cytokine expression results were subjected to statistical analysis.

RESULTS

Severe and necrotizing acute pancreatitis (AP) is characterized by the significant depletion of circulating lymphocytes. Severe acute pancreatitis is associated with a typical systemic inflammatory response syndrome and over-expression of pro-inflammatory cytokines [interleukin (IL)-6, IL-8, macrophage migration inhibitory factor (MIF)]. Serum IL-6 and MIF concentrations are the best discriminators of severe and necrotizing AP as well as possible fatal outcome during the early course of the disease.

CONCLUSION

Deregulation of cellular immune system is a key event leading to severe and necrotizing AP. IL-6 and MIF could be used as early predictors of complications.

Effect of end-stage renal disease on B-lymphocyte subpopulations, IL-7, BAFF and BAFF receptor expression

BACKGROUND

End-stage renal disease (ESRD) results in increased susceptibility to infections, impaired response to vaccination and diffuse B-cell lymphopenia. However, the precise nature and mechanism of ESRD-induced B-cell lymphopenia remains unclear. Therefore, we studied the distribution of major B-cell subsets, B-cell growth, differentiation and survival factors, IL-7 and BAFF, and their receptors in 21 haemodialysis patients and 21 controls.

METHODS

Innate B1 cells (CD19+, CD5+), conventional B2 cells (CD19+, CD5-), newly formed transitional B cells (CD19+, CD10+, CD27-), naïve B cells (CD19+, CD27-) and memory B cells (CD19+, CD27+) and BAFF receptor were quantified by flow cytometry. Plasma IL-7, BAFF, IL-6, TNF-alpha and IL-10 were measured by ELISA.

RESULTS

The ESRD group exhibited significant reductions of all B-cell subpopulations except for transitional B cells that were less severely affected. No significant difference was found in B-cell apoptosis between the ESRD and control groups. Moreover, plasma IL-7 and BAFF levels were elevated in ESRD patients, therefore excluding their deficiencies as a possible culprit. However, BAFF receptor expression was significantly reduced in transitional but not mature B cells in the ESRD group. Interestingly, B-cell activation with the TLR9 agonist resulted in significantly greater production of IL-6 and TNF alpha but not IL-10 in the ESRD group.

CONCLUSIONS

Thus, despite elevation of B-cell growth, differentiation and survival factors, ESRD patients exhibited diffuse reduction of B-cell subpopulations. This was associated with the down-regulation of BAFF receptor in transitional B cells. The latter can, in part, contribute to B-cell lymphopenia by promoting resistance to the biological actions of BAFF that is a potent B-cell differentiation and survival factor.

FOXP3+ regulatory T-cells in chronic kidney disease: molecular pathways and clinical implications

CD4+/FOXP3+ regulatory T-cells (Tregs) are essential for the maintenance of self-tolerance and Tregs deficiency results in spontaneous autoimmunity in both mice and humans. The forkhead box P3 (FOXP3) expression is required for both survival of Tregs precursors as well as their function. This suggests that Tregs may use multiple mechanisms to limit autoimmunity and may reflect functional heterogeneity among Tregs subsets that localize to distinct tissue environments. Both cell contact- and cytokine-based immunosuppressive mechanisms would require that Tregs be in close proximity to their targets. The fundamental regulatory activity that can be consistently demonstrated by Tregs in vivo and in vitro has stimulated great interest in developing novel strategies for treating ongoing inflammatory conditions. Patients with end-stage kidney disease (ESKD) are known to display a cellular immune dysfunction. Uremic solutes that accumulate during ESKD may be involved in these processes. In these patients, oxidative stress induced by oxLDL may increase Tregs sensitivity to Fas-mediated apoptosis in part as a consequence of 26S proteasome activation. The 26S proteasome, an ATP-dependent multisubunit protease complex found in the cytoplasm and in the nucleus of all eukaryotic cells, constitutes the central proteolytic machinery of the ubiquitin/proteasome system. Considering the effect of uremia and oxLDL, Tregs from patients with ESKD exhibit early cell-cycle arrest and become apoptotic. These phenomena are the consequence of the oxLDL inhibited proteasome proteolytic activity of p27(Kipl) and Bax proteins in Tregs. This may be one mechanistic explanation of the cellular immune dysfunction in patients with ESKD and may have important implications in clinics, since this response could contribute to the micro-inflammation and atherogenesis encountered in this population.

Inflammation, T-cell phenotype, and inflammatory cytokines in chronic kidney disease patients under hemodialysis and its relationship to resistance to recombinant human erythropoietin therapy

BACKGROUND

Resistance to recombinant human erythropoietin (rhEPO) occurs in some chronic kidney disease (CKD) patients, which may be due to enhanced systemic inflammatory response and to the erythropoiesis-suppressing effect of pro-inflammatory cytokines, some of which are produced by T cells.

AIM OF STUDY

The aim of this study was to investigate the relationship between resistance to rhEPO therapy in hemodialysis CKD patients and inflammatory markers [C-reactive protein (CRP), soluble interleukin (IL)-2 receptor (sIL2R), and serum albumin levels], blood cell counts, T-cell phenotype, cytokine production by T cells, and serum cytokine levels.

MATERIALS AND METHODS

We studied 50 hemodialysis CKD patients, 25 responders and 25 nonresponders to rhEPO, and compared them to each other and with 25 healthy controls. When compared to controls, CKD patients showed increased serum levels of CRP, IL-6, and sIL2R and a T-cell lymphopenia, due to decreased numbers of both CD4+ and CD8+ T cells. T cells from CKD patients had an immunophenotype compatible with chronic T-cell stimulation as shown by the increased percentage of CD28-, CD57+, HLA-DR+, CD28-HLA-DR+, and CD57+ HLA-DR+ T cells and produce higher levels of IL-2, INF-gamma, and TNF-alpha after short-term in vitro stimulation, although Th1 cytokines were not detectable in serum. Statistically significant differences were found between responders and nonresponders to rhEPO therapy for total lymphocyte and CD4+ T-lymphocyte counts, albumin (lower in nonresponders) and CRP (higher in nonresponders) levels.

CONCLUSION

CKD patients under hemodialysis present with raised inflammatory markers and decrease of total lymphocyte and CD4+ T-lymphocyte counts when compared with controls. Some of those markers are even further enhanced in nonresponders to rhEPO therapy patients, but resistance to this therapy cannot be justified by a Th1 polarized T-cell response.

Aspects of immune dysfunction in end-stage renal disease

End-stage renal disease (ESRD) is associated with significantly increased morbidity and mortality resulting from cardiovascular disease (CVD) and infections, accounting for 50% and 20%, respectively, of the total mortality in ESRD patients. It is possible that these two complications are linked to alterations in the immune system in ESRD, as uremia is associated with a state of immune dysfunction characterized by immunodepression that contributes to the high prevalence of infections among these patients, as well as by immunoactivation resulting in inflammation that may contribute to CVD. This review describes disorders of the innate and adaptive immune systems in ESRD, underlining the specific role of ESRD-associated disturbances of Toll-like receptors. Finally, based on the emerging links between the alterations of immune system, CVD, and infections in ESRD patients, it emphasizes the potential role of the immune dysfunction in ESRD as an underlying cause for the high mortality in this patient population and the need for more studies in this area.

Disturbances of acquired immunity in hemodialysis patients

Acquired immunity disturbances in hemodialysis (HD) patients are many and diverse. They are caused by uremia per se, the HD procedure, chronic renal failure complications, and therapeutic interventions for their treatment. Current data suggest that acquired immunity disturbances in HD patients concern mainly the T-lymphocyte and the antigen-presenting cell (APC). The T-lymphocyte-dependent immune response is deficient, predisposing to infections and inadequate response to vaccinations. In addition, APCs are preactivated, which seems to be responsible for the malnutrition-inflammation-atherosclerosis syndrome, and also affects T-lymphocyte function. At the molecular level it is assumed that the interaction between the APC and the T-lymphocyte is impaired. This disturbance is likely to concern the signal that results from the interaction between the major histocompatibility complex:peptide complex on APC surfaces and T-cell receptors on T-lymphocyte surfaces, or the signal that results from the interaction among the co-receptors of these two cells. The aim of the present review was to collect and classify the available clinical and experimental data in this area. Although many pieces are still missing from the puzzle, a better understanding of the responsible molecular mechanisms, will potentially lead to increased survival and a better quality of life in HD patients.

Dialysis Membrane-Induced Oxidative Stress: Role of Heme Oxygenase-1

Dialysis membranes have been reported to induce monocyte apoptosis. We studied the role of oxidative stress in the induction of dialysis membrane-induced monocyte apoptosis. Superoxide dismutase, a superoxide scavenger, prevented dialysis membrane-induced monocyte apoptosis. Similarly, other antioxidants also inhibited dialysis membrane- induced apoptosis. In addition, the interaction of dialysis membranes with monocytes was associated with the generation of molecules leading to oxidative stress such as superoxide and TBARS. Interestingly, pre-induction of heme oxygenase (HO)-1 by hemin prevented dialysis membrane-induced monocyte apoptosis, whereas inhibition of HO-1 activity (treatment with tin protoporphyrin, SN-P) enhanced dialysis membrane-induced monocyte apoptosis. We suggest that oxidative injury associated with dialysis membrane and monocyte interaction plays a role in monocyte injury. Pre-induction of HO-1 may attenuate dialysis membrane-induced monocyte apoptosis.

Pharmacodynamics of rituximab in kidney allotransplantation

The anti-CD20 antibody rituximab has recently gained interest as a B-cell depleting agent in renal transplantation. However, little is known about the pharmacodynamics of rituximab in renal transplant recipients. We have therefore studied the effect of single-dose rituximab in combination with conventional triple immunosuppressive therapy on the B-cell population in peripheral blood as well as in tissues. A total of 49 renal transplant recipients received single-dose rituximab, as induction therapy (n = 36) or as anti-rejection therapy (n = 13). We counted B cells in peripheral blood and performed immunohistochemical staining on lymph nodes and kidney transplant tissue samples to assess the prevalence of B cells. In all but 6 patients (88%) complete depletion of B cells in peripheral blood was achieved. In adults, 15 months after treatment the CD19+ and CD20+ cell counts were still below 5 cells/muL in the majority of patients (78%). The immunohistochemical staining showed a complete elimination of B cells in kidney tissue and a reduction of B cells in lymph nodes. In conclusion, single-dose rituximab in kidney transplant recipients evokes a long-term elimination of B cells in peripheral blood as well as within the kidney transplant. The effect seems to extend beyond the expected 3-12 months observed in lymphoma patients.

Alteration of peripheral blood lymphocyte subsets in acute pancreatitis

AIM: To evaluate peripheral blood lymphocyte subsets in patients with acute pancreatitis (AP).

METHODS: Twenty patients with mild AP (M-AP) and 15 with severe AP (S-AP) were included in our study. Peripheral blood lymphocytes were examined at d 1-3, 5, 10 and 30 by means of flow cytometry.

RESULTS: A significant depletion of circulating lymphocytes was found in AP. In the early AP, the magnitude of depletion was similar for T- and B- lymphocytes. In the late course of S-AP, B-lymphocytes were much more depleted than T-lymphocytes. At d 10, strong shift in the CD7+/CD19+ ratio implicating predominance of T- over B-lymphocytes in S-AP was found. Among T-lymphocytes, the significant depletion of the CD4+ population was observed in M-AP and S-AP, while CD8+ cells were in the normal range. Lymphocytes were found to strongly express activation markers: CD69, CD25, CD28, CD38 and CD122. Serum interleukin-2 (IL-2), IL-4, IL-5, IL-10, interferon-γ (IFN-γ) and tumor necrosis factor-α (TNF-α) levels were significantly increased in both forms of AP. The magnitude of elevation of cytokines known to be produced by Th2 was much higher than cytokines produced by Th1 cells.

CONCLUSION: AP in humans is characterized by significant reduction of peripheral blood T- and B-lymphocytes.

[Diagnosis of lymphocytopenia]

Lymphopenia is defined as a peripheral lymphocyte count lower than 1500/mm3 in adults and 4500/mm3 in children younger than eight months of age. We propose a classification of lymphopenia according to the mechanism involved: lymphocyte production defects, including primary immune deficiencies and immune deficiencies secondary to malnutrition or zinc deprivation; excess catabolism, due to causes including radiotherapy, chemotherapy, immunosuppressive therapy, HIV infection, and systemic lupus erythematosus; abnormal lymphocyte trapping, including mainly splenomegaly, certain viral infections, septic shock, extended burns, systemic granulomatosis, and corticosteroids; other causes of lymphocytopenia, with mechanisms that remain poorly understood: ethnicity (Ethiopians), lymphoma, renal insufficiency, and idiopathic CD4 lymphocytopenia.

Intracellular cytokines in peripheral blood leucocytes in children with chronic renal failure

We have previously shown that children with mild renal impairment show significant changes in leucocyte subsets and circulating cytokines, indicating that these patients show an increased inflammatory state. We hypothesised that measurement of intracellular cytokine production by lymphocytes and monocytes would more precisely define the immunological mechanism associated with the inflammatory state in children with pre-dialytic chronic renal failure. Blood was collected from children with chronic renal failure (CRF) who were not yet on dialysis and an age-matched control group. Leucocyte subsets and intracellular cytokine production were determined using flow cytometry. Children with CRF showed increased production of interleukin (IL)-12 by monocytes accompanied by decreased production of interferon (IFN)-gamma and increased production of IL-4 by T cells. There were no significant changes in the production of IL-8, IL-10, IL-6, IL-1alpha or tumour necrosis factor (TNF)-alpha by monocytes or in IL-2 or TNF-alpha production by T cells. There were no significant differences in total white cell count or lymphocyte count. There was a significant decrease in both B and NK cells. This study examines intracellular cytokine production in children with CRF in detail. It is the first to show that children with relatively mild renal failure display significant immunological changes of lymphocyte subsets and leucocyte cytokine production. These data provide a more accurate understanding of the immunological changes that may contribute to the clinical manifestations and progression of the disease.

Progressive loss of renal function is associated with activation and depletion of naive T lymphocytes

We hypothesized that progressive loss of renal function specifically affects certain T cell subsets. T lymphocyte subsets of patients with chronic kidney disease and healthy controls were characterized by flow cytometry using heparin-anticoagulated whole blood samples. Plasma interleukin (IL)-7 and IL-15 concentrations were determined as these cytokines are critically involved in T cell homeostasis. The results revealed that a progressive decrease in renal function is associated with activation and selective loss of naive T cells and CD4+ central memory cells and a marked increase in CD8+ memory T cells that lack CD45RO and CCR7. The profile of T cell subsets of patients with CKD 5 with or without hemodialysis treatment was similar except for a pronounced shift to Th1 cells in hemodialysis patients. IL-7 but not IL-15 plasma concentrations were lowered in patients with end-stage renal disease as compared to healthy controls.

How to interpret and pursue an abnormal complete blood cell count in adults

A complete blood cell count (CBC) is one of the most common laboratory tests in medicine. For example, at our institution alone, approximately 1800 CBCs are ordered every day, and 10% to 20% of results are reported as abnormal. Therefore, it is in every clinician's interest to have some understanding of the specific test basics as well as a structured action plan when confronted with abnormal CBC results. In this article, we provide practical diagnostic algorithms that address frequently encountered conditions associated with CBC abnormalities including anemia, thrombocytopenia, leukopenia, polycythemia, thrombocytosis, and leukocytosis. The objective is to help the nonhematologist recognize when a subspecialty consultation is reasonable and when it may be circumvented, thus allowing a cost-effective and intellectually rewarding practice.

Lymphocyte Apoptosis: Role of Uremia and Permeability of Dialysis Membrane

BACKGROUND

Uremia is associated to host defense mechanism disorders. Lymphocyte apoptosis, which may cause alteration of the immune system, is increased in uremic patients. The aim of the present study was to determine if, in addition to uremia, dialysis membranes with different biocompatibility and permeability have an effect on lymphocyte apoptosis.

METHODS

Cell apoptosis and Fas expression were assessed using flow cytometry in four groups of patients: (1) uremic non-dialyzed (Non-D) patients; (2) hemodialysis (HD) patients on hemophan; (3) low-flux polysulfone, and (4) high-flux polysulfone membrane. Ten healthy volunteers were used as controls.

RESULTS

At baseline, lymphocytes from patients on hemophan showed an increase in apoptosis (18.4 +/- 6.9%) as compared with Non-D (7.2 +/- 2.8%; p < 0.001), low-flux (6.4 +/- 2.4%; p < 0.001), high-flux (2.6 +/- 1.2%; p < 0.001) and controls (2.0 +/- 1.0%; p < 0.001). Fas expression was similar in lymphocytes from Non-D and hemophan dialyzed patients (40.5 +/- 5% vs. 40.4 +/- 6%), and in both groups it was greater than low-flux (30%+/-7%; p < 0.001), high-flux (11 +/- 4%; p < 0.001) and controls (12.6 +/- 3%; p < 0.001). When lymphocytes were cultured for 48 h, apoptosis was similar in Non-D and hemophan (27.0 +/- 4.3% vs. 27.1 +/- 6.9%); apoptosis of lymphocyte from patients on low-flux (14.1 +/- 3.5%) was greater than on high-flux polysulfone membrane (7.0 +/- 2.0%; p < 0.001).

CONCLUSION

These findings suggest that in dialysis patients lymphocyte apoptosis is influenced not only by the biocompatibility but also by the permeability of the dialysis membrane.

The imbalance in the ratio of Th1 and Th2 helper lymphocytes in uraemia is mediated by an increased apoptosis of Th1 subset

BACKGROUND

In uraemia there is a reduction in the total number of T lymphocytes and an imbalance in the ratio of Th1/Th2 T-helper (Th) lymphocytes. A higher rate of apoptosis in T lymphocytes has been reported in haemodialysis patients. The aims of the present study were to assess the Th1/Th2 pattern in uraemia and to evaluate whether a relative increase in Th1 apoptosis may explain the Th1/Th2 imbalance observed in uraemic patients.

METHODS

Seventeen non-dialysed uraemic patients were evaluated; eight healthy volunteers served as controls. Intracellular interferon-gamma (IFN-gamma) and interleukin-4 (IL-4) were measured by direct intracellular immunofluorescence and flow cytometry. Apoptosis was determined by flow cytometry using annexin V or TUNEL. Mechanisms of apoptosis were assessed by determination of Fas and Bcl-2 expression.

RESULTS

Cell production of cytokines is significantly higher in uraemic patients than in controls. In addition, in uraemic patients only 5.1+/-2.1% of the T lymphocytes contained IFN-gamma (Th1 cells) while 61.9 +/- 14.8% contained IL-4 (Th2 cells) (P < 0.0001). The percentage of apoptosis was 29.6 +/- 6.3% and 4.7 +/- 1.6% in Th1 and Th2 lymphocytes, respectively (P < 0.001). Fas expression was higher in Th1 than in Th2 cells and the expression of Bcl-2 was lower in Th1 than in Th2 cells. The apoptosis induced by anti-Fas antibodies was similar in both types of lymphocytes.

CONCLUSIONS

In uraemia there is a reduction in the proportion of Th1 lymphocytes due to a higher rate of apoptosis in this subset of lymphocytes. Th1 from uraemic patients show a higher expression of Fas and a lower expression of Bcl-2 than Th2. This makes uraemic Th1 cells more susceptible to apoptosis. The Th1/Th2 imbalance may contribute to alterations in cellular immunity observed in chronic kidney disease patients.

Induction of cell death by sera from patients with acute brain injury as a mechanism of production of autoantibodies

OBJECTIVE

To investigate the capacity of blood draining from the central nervous system of patients with acute brain injury to induce cell death, and to determine whether this phenomenon could be a way to induce the production of autoantibodies.

METHODS

The induction of cell death of several human leukemia cell lines cultured in vitro in the presence of serum collected from the brain or the systemic circulation of patients with acute brain injury was analyzed by flow cytometry after staining with annexin V and propidium iodide. The percentages of apoptotic lymphocytes derived directly from the patients were also quantified. To investigate the mechanisms responsible for the induction of cell death, the expression of apoptosis-related molecules, as well as the effect of addition of several molecules known to interfere with apoptosis, was evaluated in the cell cultures. The presence of serum autoantibodies at the time of injury and 6 months later was studied.

RESULTS

Systemic serum and, especially, serum draining from the brain lesions induced the in vitro death of the leukemia cell lines used. Moreover, there were higher percentages of ex vivo dead lymphocytes in regional blood than in systemic blood 48 hours after injury. These effects seemed to be induced by an exogenous and/or endogenous opioid, since they were blocked by the opioid antagonist, naloxone. Furthermore, such effects were mediated by an increased expression of Bax. Importantly, apoptotic Jurkat cells were bound to autoantibodies, and patients with acute brain injury produced serum autoantibodies some months after the injury. However, they did not develop a full autoimmune disease at that time.

CONCLUSION

Serum factors from acute brain injuries induce cell death, both in vivo and in vitro. Apoptotic cells and, even more so, necrotic cells in acute brain injury are potential sources for autoantigen presentation that may stimulate autoimmune responses.

Possible involvement of glutathione and p53 in trichloroethylene- and perchloroethylene-induced lipid peroxidation and apoptosis in human lung cancer cells

Trichloroethylene (TCE) and perchloroethylene (PERC) are volatile organic compounds (VOCs) that are primarily inhaled through the respiratory system. The aim of this study was to elucidate the role of glutathione (GSH) and p53 in TCE- and PERC-induced lung toxicity. Human lung adenocarcinoma cells NCI-H460 (p53-wild-type) have constitutively lower levels of GSH than NCI-H1299 (p53-null) cells. The results showed that exposure to vapor TCE and PERC produced a dose-dependent and more pronounced accumulation of H(2)O(2) in p53-WT H460 than p53-null H1299 cells. The accumulation of H(2)O(2) was accompanied by severe cellular damage, as indicated by the significant increase of lipid peroxidation and apoptosis in p53-WT H460 cells, but not p53-null H1299 cells. Cotreatment of p53-WT H460 cells with free radical scavengers, such as D-mannitol, uric acid, and sodium selenite, significantly attenuated the TCE- or PERC-induced lipid peroxidation. In contrast, depletion of GSH in p53-null H1299 cells enhanced TCE- or PERC-induced lipid peroxidation. The levels of p53 and Bax proteins were elevated, while Bcl-2 protein was downregulated in TCE- or PERC-treated p53-WT H460 cells. Activity of caspase 3, the apoptotic executioner, was also significantly enhanced in TCE- or PERC-treated cells. These data suggest that, in human lung cancer cells, GSH plays a vital role in the protection of TCE- and PERC-induced oxidative stress and apoptosis, which may be mediated through a p53-dependent pathway.

Immune dysfunction in uremia

Kidney dysfunction leads to disturbed renal metabolic activities and to impaired glomerular filtration, resulting in the retention of toxic solutes affecting all organs of the body. Cardiovascular disease (CVD) and infections are the main causes for the increased occurrence of morbidity and mortality among patients with chronic kidney disease (CKD). Both complications are directly or indirectly linked to a compromised immune defense. The specific coordinated roles of polymorphonuclear leukocytes (PMNLs), monocytes/macrophages, lymphocytes and antigen-presenting cells (APCs) in maintaining an efficient immune response are affected. Their normal response can be impaired, giving rise to infectious diseases or pre-activated/primed, leading to inflammation and consequently to CVD. Whereas the coordinated removal via apoptosis of activated immune cells is crucial for the resolution of inflammation, inappropriately high apoptotic rates lead to a diminished immune response. In uremia, the balance between pro- and anti-inflammatory and between pro- and anti-apoptotic factors is disturbed. This review summarizes the interrelated parameters interfering with the immune response in uremia, with a special focus on the non-specific immune response and the role of uremic toxins.