Uremic serum effects on peripheral blood mononuclear cell and purified T lymphocyte responses.

We have studied the effects of uremic serum on the activation state and function of normal lymphocytes in vitro, by examining both accessory cell-dependent and accessory cell-independent responses. Uremic serum was obtained from patients on conservative treatment and from the same patients after they have undergone six months of maintenance hemodialysis. Uremic serum inhibited the proliferative responses to mitogens and to recombinant IL-2 (rIL-2) of both peripheral blood mononuclear cells (PBMC) and purified T cell populations. However, the responsiveness to IL-2 of pre-formed lymphoblasts, obtained from both PBMC and purified T cells, in the presence of uremic serum was similar to that obtained in the presence of normal serum, or was even enhanced. Uremic serum did not affect the cellular IL-2 receptor alpha (IL-2R) generation though it inhibited significantly the release of soluble IL-2 receptor (sIL-2R) and the production of IL-2 after mitogenic stimulation. Uremic serum from patients after six months of hemodialysis enhanced, but did not completely restore, proliferative responses and IL-2 production by control PBMC. Neither IL-1 nor IL-2R, which are present at elevated concentrations in uremic serum, appeared to be responsible for serum effects on in vitro responses of control lymphocytes. In conclusion, our results indicate that uremic serum affects both accessory cell-mediated and accessory cell-independent normal T cell responses. Uremic serum inhibition of T cell proliferation is associated with down-regulation of IL-2 synthesis by lymphocytes and the induction of an abnormal state of activation of lymphoblasts which is further enhanced following chronic hemodialysis.     

Mechanism of increased serum soluble interleukin-2 receptor levels in patients on continuous ambulatory peritoneal dialysis.

OBJECTIVE: The aim of this study was to investigate the mechanism underlying the increase of serum soluble interleukin-2 receptor (IL-2R) levels in patients on continuous ambulatory peritoneal dialysis. MATERIAL AND METHODS: In 13 dialysis patients and 17 healthy controls, serum soluble IL-2R levels were determined by enzyme-linked immunosorbent assay, and CD25-positive (cell surface IL-2R-positive) cells were detected by flow cytometry. Soluble IL-2R levels were also measured in the supernatant of cultured peripheral blood mononuclear cells. RESULTS: The serum soluble IL-2R level was significantly higher in the patients than in the healthy controls (p < 0.0001). In contrast, both the percentage and the absolute count of CD25-positive cells showed no significant differences, and neither did the soluble IL-2R level in culture supernatant. Serum soluble IL-2R levels showed a positive correlation with the serum beta2-microglobulin level (p < 0.01), the age of the patients (p < 0.05), and duration of dialysis (p < 0.05), as well as a negative correlation with the urine volume (p < 0.05). CONCLUSIONS: The increase of serum soluble IL-2R in patients on peritoneal dialysis may be caused by accumulation due to its low transperitoneal clearance and low urinary excretion.     

Vitamin E-loaded dialyzer resets PBMC-operated cytokine network in dialysis patients

BACKGROUND: In hemodialysis patients the activity of stimulated Th1 lymphocytes is depressed, while Th2 cells are constitutively primed. Such phenomena may depend on monocyte activation and altered release of interleukin (IL)-12 and IL-18, which regulate Th cell differentiation. Reactive oxygen species (ROS) activate monocytes; therefore, a hemodialyzer with antioxidant activity would contrast ROS, prevent monocyte activation, reset IL-12 and IL-18 release, and restore Th1/Th2 balance. METHODS: Ten patients on regular dialysis treatment (RDT) with cellulosic membrane (CM) were shifted to vitamin E-coated dialyzer (VE). During treatment with CM and after 3, 6, and 12 months of treatment with VE, peripheral blood mononuclear cells (PBMC) and purified CD4+ cells were isolated, and cultured, resting, mitogen-stimulated, and interferon gamma (IFNgamma), IL-4, IL-10, IL-12, and IL-18 release was measured. Vitamin E and A plasma levels and the effects of a single dialysis session on peripheral blood NO levels were assayed. RESULTS: The constitutive release of IL-4 and IL-10 by CD4+ cells was abated significantly by treatment with VE (nadir -77.8% and -55.3%, respectively, at 12 months). INFgamma release by mitogen-stimulated CD4+ recovered with VE (zenith +501% at 12 months). PBMC constitutive production of IL-12 and IL-18 was significantly reduced by VE (nadir at 12 months -64.7% and -51.3%, respectively). VE increased plasma levels of vitamins E and A. NO plasma levels fell after a single dialysis treatment with VE (-17%, P < 0.05) in contrast with CU (+27.1%, P < 0.05). CONCLUSION: The network of cytokines released by monocytes and Th cells is reset toward normality by treatment with vitamin E-coated dialyzer.     

Production and kinetics of interleukin-1 in hemodialysis. In vivo and in vitro study

Interleukin-1-beta (IL-1-beta) was measured in the plasma and peripheral blood mononuclear cell lysates of uremic patients undergoing maintenance hemodialysis by means of either cuprophane or polysulfone membranes. Basal plasma levels of IL-1-beta in hemodialyzed patients were strikingly higher than those of uremic patients on conservative treatment or of healthy subjects. Plasma levels of IL-1-beta in uremic patients increased significantly after 3 and 6 months of hemodialysis. The study of the kinetics of IL-1-beta concentration during a single hemodialysis session revealed that the concentration of IL-1-beta fell to 21 and 22% of the predialysis level with cuprophane and polysulfone, respectively. Hemodialysis patients also had a significantly higher intracellular IL-1-beta level than normal controls. During the hemodialysis session, an increase in cell-associated IL-1-beta was seen regardless of the membrane employed. In a parallel study, normal mononuclear cells were subjected to closed-loop in vitro dialysis with either cuprophane or polysulfone membranes, with or without acetate buffer. After 120 min of recirculation, an increase in cell-associated IL-1-beta was detected, but no changes were seen in the circulating medium. IL-1-beta production was not significantly influenced by either membrane or the dialysate composition. Hemodialysis has been associated with high plasma- and cell-associated IL-1 levels. The kinetics of intradialytic changes of IL-1-beta levels make IL-1 an unlikely cause of acute complications in hemodialysis. On the other hand, a chronic elevation of IL-1 in plasma of patients on maintenance hemodialysis may contribute to the development of some of the long-term complications of this treatment.     

Hemodialysis related induction of interleukin-6 production by peripheral blood mononuclear cells.

Interleukin-6 (IL-6) has a complex spectrum of biological activities, for example, growth and differentiation of B cells and synthesis of acute-phase proteins by the liver. To evaluate the role of this cytokine in the inflammatory response induced by blood interaction with hemodialysis membranes, we have investigated the IL-6 synthesis and release in supernatant of 24-hour cultured peripheral blood mononuclear cells (PBMC) isolated from: (a) 10 hemodialyzed patients, (b) seven patients with advanced chronic renal failure (GFR less than or equal to 10 ml/min), and (c) eight healthy control subjects. In the same groups of subjects we evaluated the relationship between IL-6 synthesis and release and beta-2-microglobulin (beta 2m) production. Before and after dialytic treatment hemodialysis patient blood samples were drawn using the following criteria: (1) after two months of dialysis with cuprophan membranes, (2) after one and two months of dialysis with polymethylmethacrylate (PMMA) membranes, and finally, (3) after one further month of dialysis with cuprophan membranes. IL-6 was determined after 72 hours of incubation of PBMC supernatant serial dilutions with IL-6-dependent hybridoma cell line, 7TD1. Compared to IL-6 synthesis in control subjects (6.0 +/- 5.6 U/3 x 10(6) PBMC/24 hr), hemodialyzed patients, when treated with cuprophan membranes, showed significantly higher value of IL-6 production both before (23 +/- 13 U/3 x 10(6) PBMC/24 hr) and after (26.2 +/- 11.3 U/3 x 10(6) PBMC/24 hr) the dialytic session.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of different anaesthetic agents on immune cell function in vitro

BACKGROUND AND OBJECTIVE: Anaesthesia may affect the regulatory balance of postoperative immune response. The aim of this study was to investigate the effects of different volatile and non-volatile anaesthetic agents and particularly of clinically used agent combinations on the proliferation capacity and cytokine production of immune cells. METHODS: Peripheral blood mononuclear cells from healthy donors were PHA-activated in the presence or absence of various concentrations of thiopental, propofol, fentanyl, sufentanil, sevoflurane, nitrous oxide and combinations of these anaesthetics. Cell proliferation was assessed by tritiated thymidine uptake. Interleukin-2 production and release of the soluble IL-2 receptor were determined by enzyme immunoassays and used as measures of lymphocyte activation. RESULTS: Thiopental inhibited cell proliferation in a dose dependent manner (P < 0.001) and reduced sIL-2R release (2090-970 microg mL(-1); P < 0.05). Propofol reduced sIL-2R release at the high concentration of 10 microg mL(-1) (2220 pg mL(-1) 1780 microg mL(-1); p < 0.05). Fentanyl and sufentanil did not compensate for or enhance the inhibitory effects of thiopental. Nitrous oxide, but not sevoflurane, reduced the proliferation of human peripheral blood mononuclear cells (P < 0.05). In combinations with thiopental or nitrous oxide, sevoflurane compensated the inhibitory effects of these two agents. Fentanyl, sufentanil, sevoflurane and nitrous oxide did not affect PHA-induced IL-2 and sIL-2 receptor release by human peripheral blood mononuclear cells. CONCLUSION: Thiopental and nitrous oxide have immunosuppressive activity. In contrast, sevoflurane may have a beneficial effect by alleviating the immunosuppressive effects of both substances.     

Hemodialysis with cuprophane membrane modulates interleukin-2 receptor expression

Chronic dialysis patients have several indices of immune deficiency. We examined the hypothesis that the biocompatibility of dialysis membranes may influence the ability of lymphocytes to express interleukin-2 (IL-2) receptors on their surface, a key event in cellular immune response. We investigated the potential role of the dialysis membrane in eight chronic hemodialysis patients. The study design was a cross-over study using cuprophane and polymethylmethacrylate (PMMA) membranes. Chronic dialysis with new cuprophane membrane leads to an increase in baseline expression of the two subunits of IL-2 receptors. IL2R alpha (p55, CD25) and IL-2R beta (p70), in peripheral blood mononuclear cell (PBMC). However, Phytohemagglutinin (PHA) stimulation of PBMC harvested after two weeks of dialysis with cuprophane membrane showed a markedly decreased expression of high affinity IL-2 receptors. These findings are reversed when patients were dialyzed with a PMMA membrane which is also associated with minimal complement activation. The increased expression of IL-2 receptor subunits are reproduced in vitro by direct contact of PBMC with cuprophane membrane and by the addition of the anaphylatoxin C5a. This study confirms the participation of lymphocytes in the complex blood-membrane interactions that occurs during dialysis; the results may be relevant to observations of immune deficiency in dialysis patients.     

Ex vivo flow cytometry determination of intracytoplasmic expression of IL-2, IL-6, IFN-gamma, and TNF-alpha in monocytes and T lymphocytes, in chronic hemodialysis patients

AIMS: To determine the intracytoplasmic expression of TNF-alpha, IL-2, IL-6 and IFN-gamma, ex vivo and in vitro, in both monocytes and T lymphocytes by flow cytometry after appropriate stimulation using phorbol myristate acetate (PMA)/ionomycin or lipopolysaccharides (LPS) in the presence of monensin, in order to assess the bio(in)compatibility of different dialysis membranes. METHODS: We examined monocytes and T lymphocytes taken from chronic hemodialysis patients (using either cuprophane (CUP), n = 6; polyacrylonitrile (AN 69), n = 6; or polysulfone (PS), n = 6 membranes), before and after a dialysis session. We compared the results with those obtained from end-stage chronic renal failure patients (n = 3) and healthy volunteers (n = 11). RESULTS: Before any stimulation there was a statistically significant difference in the percentages of TNF-alpha, IL-6, and IFN-gamma- expressing monocytes with respect to the dialysis membrane used. The highest percentages were observed for CUP and AN69 patients with figures of around 30% for each cytokine; the lowest percentages were found in PS patients and healthy volunteers. One hour after LPS stimulation the patterns remained unchanged for TNF-alpha and IFN-gamma, whereas the percentages of IL-6-expressing cells in PS patients and in healthy volunteers reached the figures obtained in the other groups. When we examined the percentage of IFN-gamma-, TNF-alpha- and IL-6-expressing monocytes in patients before and after a dialysis session, before any stimulation, we found that the results were significantly different for the three membranes (p = 0.01). Thus, a dialysis session with polysulfone membranes had no significant effect on the precentages of IFN-gamma-, TNF-alpha-, and IL-6-expressing monocytes, whereas percentages were significantly lower after the dialysis session when using cuprophane or AN69 membranes, suggesting a release of these cytokines by the monocytes during dialysis. A significant number of IFN-gamma- and IL-2-expressing T lymphocytes were only detected after 18 hours of PMA/ionomycin stimulation. The percentages of IFN-gamma-expressing T cells recorded for the different membranes were not statistically different from those recorded for healthy subjects or pre-dialysis patients, i.e., they were between 11.5 and 20%. However, the percentages of IL-2-expressing T lymphocytes were significantly different between the 5 groups, i.e., 31.3, 30.5, 18.6, 13.9 and 7. 6%, respectively, for CUP patients, pre-dialysis patients, healthy volunteers, PS and AN69 patients. This suggests that pre-dialysis and CUP patients have, at baseline, a stimulation of their T lymphocytes. Finally, a 4-hour dialysis session had no impact on the percentages of IL-2-expressing T lymphocytes, whereas it was associated with a significant decrease in the percentage of IFN-gamma-expressing cells, but only when cuprophane membranes were used. CONCLUSION: Cytokine flow cytometry enables one to study, ex vivo, i.e., without any stimulation of the cells, and in vitro after appropriate stimulation, the bio(in)compatibility of dialysis membranes assessed by the intracytoplasmic cytokine profiles of TNF-alpha, IFN-gamma, IL-6 and IL-2, evaluated at the single cell level.     

Changes in fibrinolytic activity during the course of a single hemodialysis session

Cardiopulmonary bypass, a form of extracorporeal circulation, markedly increases blood fibrinolytic activity. Accordingly, we measured the effect of hemodialysis, another form of extracorporeal circulation, on fibrinolytic activity in 13 patients with end stage renal disease during and after a single hemodialysis session. Total fibrinolytic activity on fibrin plates, which reflects plasminogen activator levels, was below normal prior to dialysis, rose well above normal at one hour, and then dropped gradually so that just prior to the end of a dialysis session it was still significantly elevated. Within 30 minutes of the end of dialysis, fibrinolytic activity fell rapidly, approaching predialysis levels. In contrast, 5 patients studied before and 3 hours into a peritoneal dialysis session showed no change in their subnormal levels of plasminogen activator. Plasminogen and alpha-2 antiplasmin levels did not change significantly during the course of hemodialysis. Thus, hemodialysis, but not peritoneal dialysis, transiently increases fibrinolytic activity without consuming plasminogen, a pattern consistent with the release of tissue type plasminogen activator.     

Impact of dialyzer membrane selection on cellular responses in acute renal failure: a crossover study

BACKGROUND: When acute renal failure (ARF) is severe enough to require dialysis, in-hospital mortality rates approach 60%. These alarming figures have been ascribed in part to advanced age and the high prevalence of comorbid conditions. In the past several years, a number of attempts have been made to investigate the impact of dialyzer membrane type on clinical outcomes. Unfortunately, to date, clinical studies addressing this question have reported conflicting results. METHODS: This crossover study examined the effect of dialyzer membrane type on cytokine synthesis by peripheral blood mononuclear cells (PBMCs), superoxide release by neutrophils, and apoptosis or programmed cell death of neutrophils in 24 patients with ARF requiring intermittent hemodialysis. The patients were assigned in an alternate order to a low-flux cellulose acetate (CA) or polysulfone (PS) dialyzer. After three consecutive dialysis sessions, patients were crossed over to the second dialyzer for three additional treatments. These cellular responses were measured upon dialyzer assignment and at the third and sixth dialysis session in relationship to the dialyzer type. RESULTS: The results of the study showed no impact of dialyzer biocompatibility on synthesis of tumor necrosis factor-alpha (TNF-alpha) or interleukin 10 (IL-10) by PBMCs, superoxide release by neutrophils, or neutrophil apoptosis. This held true regardless of the initial dialyzer assignment. Furthermore, there was no correlation between dialysis adequacy (measured by single-pool Kt/V) and postdialysis cellular responses. CONCLUSIONS: In summary, this study refines the question of biocompatibility by comparing a substituted cellulose rather than unsubstituted cellulose dialyzer to a PS dialyzer in the setting of ARF. The results failed to demonstrate a dialyzer advantage on the selected cellular responses.     

Effect of membrane composition on cytokine production and clinical symptoms during hemodialysis: a crossover study

BACKGROUND: Intradialytic symptoms including hypotension have been reported during dialysis and it has been suggested that these are related to the release of cytokines like IL-1beta and TNFalpha by blood mononuclear cells when they get activated either due to contact with the dialyzer membrane or by compliment activation. OBJECTIVE: To study the relationship between hemodialysis symptoms, cytokine production, and dialyzer membrane composition. METHOD: In a randomized prospective crossover study, 20 ESRD patients on maintenance hemodialysis were studied over cuprophan (CU) and polysulfone (PS) low flux dialyzer membranes for three weeks each undergoing a biweekly dialysis schedule of 4 h sessions. Serial IL-1beta and TNFalpha levels were measured over 0, 15, 240 min during the first use of the dialyzer for all patients on both membranes. Intradialytic symptoms were monitored in a total of 240 dialysis sessions. RESULTS: IL-1beta levels increased from 16.6 +/- 2.2 to 64.8 +/- 25.1 pg/mL on CU and 21.5 +/- 3.7 to 103.5 +/- 30.7 pg/mL on PS membrane over the 4-h dialysis session. Similarly TNFalpha increased from 42.8 +/- 4.5 to 354.9 +/- 80.4 pg/mL on CU and 117.1+/- 53.7 to 387.0 +/- 78.0 pg/mL on PS membrane. IL-1beta levels increased significantly with PS membrane while TNFalpha rise was significant with both the membranes. Nausea was the most common symptom occurring in 138 dialysis sessions (57.5%). Vomiting, chest pain, fever, chills, and breathlessness occurred significantly more during dialysis with CU membrane as compared with PS membrane (P < 0.01). Nausea, cramps, back pain, itching, restlessness, post dialysis fatigue, and hypotension did not differ between the two membranes. The mean rise in the cytokine levels during the first 15 min of sessions where the symptoms occurred, when compared with the mean rise in sessions where the symptoms did not occur, did not reveal any significant difference. Cytokine release did not correlate with the occurrence of intradialytic symptoms. CONCLUSION: Both CU and PS membranes increase circulating cytokine levels. More intradialytic clinical symptoms are seen in dialysis with CU as compared with PS membrane but the rise in cytokines IL-1beta and TNFalpha does not appear to be responsible for them.     

Release of interleukin-6 and its soluble receptors by activated peripheral blood monocytes is elevated in hypocholesterolemic hemodialysis patients

BACKGROUND: A reverse association between cholesterol level and cardiovascular disease mortality is observed in hemodialysis (HD) patients; this paradoxical relationship may be explained by the coexistence of inflammation. Interleukin-6 (IL-6) is a central regulator of inflammation; its action is augmented by the soluble IL-6 receptor (sIL-6R) and inhibited by the soluble gp130 (sgp130). In order to investigate the potential association of inflammation with cholesterol levels in the HD population, release of soluble IL-6 components by peripheral blood mononuclear cells (PBMCs) was measured in two groups of HD patients with distinctly different lipid profile and in a control group. METHODS: Twenty-two HD patients with low serum cholesterol (range 85-171 mg/dl), 23 HD patients with high cholesterol (189-342 mg/dl) and 21 normolipidemic non-renal failure subjects were enrolled in the study. IL-6, sIL-6R and sgp130 were measured by ELISA in the serum and in the supernatant collected from cell cultures of activated or resting PBMCs isolated from all three groups. RESULTS: Serum IL-6 and sgp130 level was higher while sIL-6R was lower in both groups of HD patients compared to the control group. The ex-vivo release of the IL-6 and sgp130 by unstimulated PBMCs did not differ significantly between the three groups but that of the sIL-6R was higher in non-renal failure than in hypercholesterolemic HD subjects. Production of sIL-6R by stimulated PBMCs was higher in low-cholesterol HD patients (p < 0.001) and the same was valid for the sgp130 release (p = 0.034). Release of IL-6 by activated PBMCs was higher in the low-cholesterol compared to the high-cholesterol HD patients group (p = 0.011 for post hoc test). Major serum lipid fractions were inversely correlated to IL-6 and sIL-6R production from stimulated PBMCs in HD but not in non-renal failure subjects. Finally, release of the sgp130 by PBMCs was significantly reduced in 13 hypertriglyceridemic--and hypercholesterolemic--HD patients. CONCLUSION: Production of soluble components of a crucial pro-inflammatory and potentially atherogenic cytokine, namely the IL-6, by stimulated PBMCs appears to be inversely correlated with the serum cholesterol levels in HD patients.     

Immune deficiency in uremia: interleukin-2 production and responsiveness and interleukin-2 receptor expression and release

We have studied the role of interleukin-2 (IL-2) and its receptors in the impaired in vitro lymphocyte response characteristic of hemodialysis patients treated by means of cuprophane membranes. The proliferative response of T lymphocytes as well as T-cell-dependent B cell proliferation after stimulation with mitogens was significantly reduced in hemodialysis patients. The in vitro production of IL-2 after such stimulation in parallel cultures was found to be similar in patients and in controls. The expression of IL-2 receptor on the lymphocyte cellular membrane in the hemodialysis group was also similar to controls. The in vitro proliferative response of uremic lymphocytes to exogenous IL-2, however, was significantly depressed suggesting a reduced availability of biologically active IL-2 receptor. The release of soluble IL-2 receptor by lectin-stimulated lymphocytes in culture was also significantly lower in the patient group; yet, hemodialysis patients has a strikingly elevated level of plasma soluble IL-2 receptor, and similar high levels were also found in three other groups of end-stage renal disease patients dialyzed by means of cellulose acetate, polysulfone and polyacrylonitrile membranes, as well as in a group of uremic patients on conservative treatment. In the hemodialysis patient group a significant positive correlation between levels of soluble IL-2 receptor and the duration of hemodialysis was found. Since soluble IL-2 receptor has been reported to down-regulate lymphocyte responses, the elevation in plasma levels of soluble IL-2 receptor in hemodialysis patients may be a pathogenetic factor in the progressive development of impaired immunity associated with end-stage renal disease.     

Influence of Dialysis Membranes on Interleukin-1β and Interleukin-1 Receptor Antagonist Production by Peripheral Blood Mononuclear Cells

Abstract: We investigated the production of interleukin (1L)-1β and IL-1 receptor antagonist (Ra) by peripheral blood mononuclear cell (PBMC) in vitro during hemodialysis of 7 dialysis patients using 4 differential dialysis membranes (regenerated cellulose [RC], polyamide [PA], polysulfone [PSI and AN-69). Blood sampling was performed before dialysis (0 min), 15 min after starting dialysis, and after dialysis (240 min) during the last session of each treatment. The cellular content of fresh cells and the production of IL-1β and IL-1Ra with and without lipopolysaccharide (LPS) stimulation of the cells were evaluated and measured by enzyme-linked immunosorbent assay (ELISA). The level of IL-1β with LPS stimulation using RC, PA, and PS membranes was significantly reduced at 15 min and was not changed at 240 min as compared with the level at 0 min. On the other hand, the level of IL-1β with LPS stimulation using an AN-69 membrane at 15 and 240 min was not significantly different from that at 0 min. Neither initial cellular content nor spontaneous production of IL-1β were detected at 0, 15, or 240 min in any of the membranes. The spontaneous production of IL-1Ra at 15 and 240 min was not significantly different from that at 0 min in any of the membranes. The cellular content of IL-1Ra using the RC membrane was significantly lower at 15 min and did not differ at 240 min from the level at 0 min. The cellular content of IL-1Ra using PA, PS, and AN-69 membranes was not significantly different at 15 and 240 min from that at 0 min. However, the IL-1Ra level with LPS stimulation using RC and PA membranes was significantly reduced from that at 0 min, but the level using PS and AN-69 membranes was not different from that at 0 min. Because IL-1β and IL-1Ra levels 15 min after starting dialysis using bioincompatible dialysis membranes were reduced from the levels at 0 min, the findings suggest that measurement of cytokines during dialysis treatment at an early stage is a useful marker for evaluating the biocompatibility of a dialysis membrane.     

In vitro production of interleukin-1 from blood mononuclear cells of patients on chronic hemodialysis therapy.

A monocyte defect is thought to be involved in the impaired immune response in patients on regular hemodialysis therapy. As an indicator of cell function, we studied in vitro IL-1 beta production of mononuclear cells from hemodialysis patients in comparison to normal controls. Mononuclear cells were stimulated with endotoxin or Staphylococcus epidermidis in parallel with control incubations in tissue culture medium alone. Spontaneous as well as stimulated total IL-1 beta production (cell-associated plus extracellular) did not differ significantly in cells obtained from patients compared to those from normal controls. However, the relative amounts of IL-1 beta released into the cell supernatants were significantly reduced in mononuclear cells from hemodialysis patients when stimulated with endotoxin but not with Staphylococcus epidermidis. These data indicate a stimulus-dependent defect in the mechanism of IL-1 beta release. As IL-1 is necessary for T-cell activation this alteration in mononuclear cell function may play a role in the impaired cellular immunity observed in patients on chronic hemodialysis therapy.     

Serum concentration of IL-2, IL-6, TNF-alpha and their soluble receptors in children on maintenance hemodialysis

In chronic renal failure patients a state of immunodeficiency paradoxically coexists with the activation of immune effector cells, including monocytes and lymphocytes. The activation of these cells leads to the release of cytokines. The aim of this study was to estimate the serum concentrations of IL-2, IL-6, TNF-alpha and their soluble receptors: IL-2 sRalpha, IL-6 sR, sTNF RI in children with chronic renal failure and young adults on maintenance hemodialysis (HD). The study included 16 HD patients (11 females, 5 males) aged 11-22 (mean 16.1 +/- 3.1) years and a control group of 15 age-matched healthy children. Only the mean concentration of IL-6 was similar in HD patients and the control group. The levels of the other cytokines were significantly higher in patients undergoing HD compared to the healthy subjects. No significant differences were observed between the pre- and post-dialysis values or between the values obtained using various dialyzer membranes. These data suggest that immune cells in HD children are in an activated state and that neither a single dialysis session nor the type of dialyzer membrane has an influence on the cytokines examined.     

Effect of renal replacement therapy on cellular cytokine production in patients with renal disease

To evaluate the effect of renal replacement therapy on cellular cytokine production in patients with renal disease, we studied interleukin 1 (IL-1) and interleukin-2 (IL-2) production by target cells stimulated with supernatants from cultured peripheral blood mononuclear cells from patients with end-stage renal disease, who were treated with hemodialysis and continuous ambulatory peritoneal dialysis (CAPD) before and after hemodialysis or a peritoneal dialysate exchange, compared to normal subjects used as time controls, and patients with chronic renal insufficiency. Initial cellular IL-2 production was increased in patients with hemodialysis, compared to normal controls. The ratio of pretreatment cellular IL-2 and IL-1 production was increased in all patient groups compared to normal subjects. Both hemodialysis and CAPD treatments resulted in increased cellular IL-1 (51.7%, P less than 0.007, and 42.8%, P less than 0.002, respectively) and IL-2 production (50.5%, P less than 0.015, and 33.3%, P less than 0.0008, respectively). The hemodialysis group had significantly higher cellular IL-2 production compared with normal controls' after treatment. After treatment, the IL-2/IL-1 ratio remained elevated in all groups with renal disease compared with normal subjects. We conclude patients with renal disease have an abnormal functional relationship between IL-1 and IL-2, characterized by increased IL-2 production per level of IL-1, unaffected by type or presence of renal replacement therapy.     

Effect of Membrane Composition on Cytokine Production and Clinical Symptoms During Hemodialysis: A Crossover Study

Background. Intradialytic symptoms including hypotension have been reported during dialysis and it has been suggested that these are related to the release of cytokines like IL-1β and TNFα by blood mononuclear cells when they get activated either due to contact with the dialyzer membrane or by compliment activation. Objective.?To study the relationship between hemodialysis symptoms, cytokine production, and dialyzer membrane composition. Method.?In a randomized prospective crossover study, 20 ESRD patients on maintenance hemodialysis were studied over cuprophan (CU) and polysulfone (PS) low flux dialyzer membranes for three weeks each undergoing a biweekly dialysis schedule of 4 h sessions. Serial IL-1β and TNFα levels were measured over 0, 15, 240 min during the first use of the dialyzer for all patients on both membranes. Intradialytic symptoms were monitored in a total of 240 dialysis sessions. Results.?IL-1β levels increased from 16.6 ± 2.2 to 64.8 ± 25.1 pg/mL on CU and 21.5 ± 3.7 to 103.5 ± 30.7 pg/mL on PS membrane over the 4-h dialysis session. Similarly TNFα increased from 42.8 ± 4.5 to 354.9 ± 80.4 pg/mL on CU and 117.1 ± 53.7 to 387.0 ± 78.0 pg/mL on PS membrane. IL-1β levels increased significantly with PS membrane while TNFα rise was significant with both the membranes. Nausea was the most common symptom occurring in 138 dialysis sessions (57.5%). Vomiting, chest pain, fever, chills, and breathlessness occurred significantly more during dialysis with CU membrane as compared with PS membrane (P<0.01). Nausea, cramps, back pain, itching, restlessness, post dialysis fatigue, and hypotension did not differ between the two membranes. The mean rise in the cytokine levels during the first 15 min of sessions where the symptoms occurred, when compared with the mean rise in sessions where the symptoms did not occur, did not reveal any significant difference. Cytokine release did not correlate with the occurrence of intradialytic symptoms. Conclusion.?Both CU and PS membranes increase circulating cytokine levels. More intradialytic clinical symptoms are seen in dialysis with CU as compared with PS membrane but the rise in cytokines IL-1β and TNFα does not appear to be responsible for them.     

Effect of changing from a cellulose acetate to a polysulphone dialysis membrane on protein oxidation and inflammation markers

BACKGROUND: In vitro, synthetic dialysis membranes induce less activation of blood components to produce pro-inflammatory cytokines and reactive oxygen species compared with cellulose acetate membranes. However, the long-term effect of switching from a cellulose-based dialysis membrane to a synthetic membrane on protein oxidation and systemic inflammation in hemodialysis patients is not well defined. METHODS: Nineteen patients receiving hemodialysis were followed prospectively after changing from a low-flux cellulose acetate membrane to a low-flux polysulphone membrane for 11-17 months (n = 15) and then returning to the cellulose acetate membrane for 1 month (n = 13). Plasma markers of protein oxidation, cell activation and systemic inflammation and concentrations of soluble cell adhesion molecules were measured at baseline and at the end of each intervention period. RESULTS: Plasma levels of protein thiols (18%), IL-6 (34%), VCAM-1 (33%), ICAM-1 (21%) and beta2-microglobulin (21%) increased significantly and dityrosine fluorescence (-36%), protein lipofuscin-like fluorophores (-18%) and TNF-alpha (-20%) decreased significantly in the patients after they switched to the polysulphone membrane. After reverting to the cellulose acetate membrane for 1 month, plasma levels of protein thiols and IL-6 returned to baseline while levels of other variables were not significantly different from values at the end of the polysulphone dialysis period. There was substantial intra-individual variation between 2 baseline measurements of plasma cytokines. CONCLUSIONS: Switching from a cellulose acetate membrane to a low-flux polysulphone dialysis membrane for a year or more may decrease the level of protein oxidation suggesting a decrease in oxidant stress and greater biocompatibility of the polysulphone membrane. The effect of this change in dialysis membrane on systemic inflammation is uncertain due to increases in some but not other inflammation-sensitive molecules.