Cells In Hemodialysis Patients Research Articles

Factors determining the percentage of hypochromic red blood cells in hemodialysis patients

Factors determining the percentage of hypochromic red blood cells determines iron status in hemodialysis patients. Determination of the percentage of hypochromic red blood cells (RBC; %HYPO) has been advocated as a sensitive index of functional iron deficiency during erythropoietin (EPO) therapy in hemodialyzed patients. The significance of %HYPO in chronic renal failure was evaluated in 64 chronically hemodialyzed patients. The linear correlation was determined between %HYPO and 13 variables, including age, sex, weight, C-reactive protein (CRP), ferritin, transferrin (Tf), Tf saturation, soluble Tf receptor (sTfR), serum iron (SI), urea, parathormone, dialysis dose (Kt/V), dose of EPO administered (EPO), and absolute reticulocyte count. Multiple regression analyses were then performed to select the parameters that jointly provide the best prediction of %HYPO. Univariate analysis showed significant correlations between %HYPO and iron parameters (sTfR, Tf saturation, SI, and ferritin, in decreasing order), EPO, reticulocyte count, and CRP. Multivariate analysis yielded an equation showing that the variation of %HYPO is essentially associated with the combined changes in sTfR, CRP, and EPO dosage. %HYPO is a meaningful and inexpensive parameter that reflects the integrated effects of iron stores, inflammation, and erythropoietic stimulation on iron availability in hemodialyzed patients. Among iron exchange parameters, sTfR is the best predictor of %HYPO, followed by Tf saturation, SI, and ferritin.

Peripheral deletion of T cells in haemodialysis patients

Many patients with end-stage renal disease have altered host defenses against infectious agents. We have demonstrated that T cells, which play an important role in the immunological response, may undergo apoptosis by the Fas system in uraemia. To elucidate whether gammadelta T cells, which function as a first defense against intracellular pathogens, are altered in number or characteristics in dialysis patients, surface expressions of TCR, LFA-1 and Fas antigen on peripheral T cells were examined by immunofluorescence analysis. We demonstrated that the proportions of peripheral gammadelta T cells are altered significantly in haemodialysis (HD) patients. Interestingly, there were marked differences in the levels of expression of LFA-1 and Fas antigen between the two types of T cells. Moreover, both the expression of LFA-1 and that of Fas antigen were enhanced significantly in HD patients compared with normal controls. These results suggest that circulating gammadelta T cells may be susceptible to activation-induced cell death in comparison with alphabeta T cells in uraemic environments.

IL-10 synthesis and secretion by peripheral blood mononuclear cells in haemodialysis patients.

IL-10 may explain the paradox between immunodeficiency and oversecretion of cytokines in chronic haemodialysis (HD) patients. We analysed the secretion of IL-10 by PBMC and the expression of IL-10 mRNA in 10 long-term HD patients (108-276 months), 10 short-term HD patients (3-18 months), and 10 healthy controls. Spontaneous IL-10 secretion was higher in HD patients than in controls (15 pg/ml vs 2 pg/ml, P = 0.004). It was detected in 13 of 20 patients and in 1 of 10 controls (P = 0.01). IL-10 mRNA expression was also higher in HD patients than in controls. Spontaneous secretions of IL-10 and IL-6 were positively correlated in patients. IL-10 secretion in response to LPS was higher than the upper limit of control range in 4 of 10 long-term HD patients and in no short-term HD patients (P = 0.04). IL-10 mRNA expression was also higher in long-term than in short-term HD patients. This study demonstrates that IL-10 is spontaneously synthesized and secreted in HD patients, supporting an immunomodulating role in this setting. The greater IL-10-producing capacity in long-term HD patients indicates a chronic effect of haemodialysis on PBMC responsiveness.

Interleukin-1 receptor antagonist synthesis by peripheral blood mononuclear cells in hemodialysis patients

Pro-inflammatory cytokines like interleukin (IL)-1 beta and tumor necrosis factor-alpha (TANF-alpha) are believed to play a significant role in dialysis-related morbidity. It has been previously demonstrated that the endogenous synthesis of interleukin-1 receptor antagonist (IL-1Ra) is a reliable marker of the level of IL-1 beta synthesis in hemodialysis (HD) patients. In this study, we assessed the impact of clinical and laboratory variables on IL-1Ra synthesis by peripheral blood mononuclear cells (PBMC) in patients on HD with unsubstituted cellulose dialyzers. IL-1Ra by PBMC was measured by a specific non-cross-reactive radioimmunoassay. Day to day variation in cytokine synthesis, the correlation between cytokine synthesis under different in vitro stimulatory conditions, and the influence of clinical and laboratory variables on cytokine synthesis were studied. Although there was a trend towards greater IL-1Ra synthesis by unstimulated, endotoxin-stimulated and IgG-stimulated PBMC drawn before the second and third dialysis sessions of the week when compared to the first dialysis treatment, this was not statistically significant. There was a strong correlation between IL-1Ra synthesis by PBMC cultured under different stimulatory conditions that was best observed between IL-1Ra cell content and from endotoxin-stimulated PBMC (r = 0.51, P = 0.0001), and endotoxin- and IgG-stimulated PBMC (r = 0.44, P = 0.0001). In addition, there was a close correlation between total synthesis (cell associated and secreted) and secreted levels of IL-1Ra in unstimulated (r = 0.59, P = 0.0001) and endotoxin-stimulated PBMC (r = 0.69, P = 0.0001). Interestingly, there was an inverse correlation between IL-1Ra synthesis and duration of dialysis that was strongest for secreted IL-1Ra from unstimulated (r = -0.50, P = 0.002) and endotoxin-stimulated PBMC (r = -0.34, P = 0.04). There was no significant correlation between IL-1Ra synthesis by PBMC and other clinical and laboratory indices. The observations from this study indicate that: (1) in HD patients, there were no significant differences in cytokine synthesis by PBMC drawn before the three different dialysis treatments during the week; (2) there is a close relationship between IL-1Ra synthesis from PBMC cultured under different stimulatory conditions; (3) the secreted levels of IL-1Ra correlate directly with total synthesis (cell-associated and secreted); (4) with the exception of duration of dialysis, none of the other clinical or laboratory parameters correlated with cytokine synthesis; and (5) the diminished endotoxin- or IgG-stimulated IL-1Ra synthesis with increasing time on dialysis is possibly another sign of the impaired host-defense system in patients on long-term hemodialysis.

Nifedipine reverses the abnormalities in [Ca2+]i and proliferation of B cells from dialysis patients

Both animals and patients with chronic renal failure have impaired B cell function due, in part, to elevated levels of cytosolic calcium ([Ca2+]i). Treatment of HD patients with nifedipine has normalized [Ca2+]i of their polymorphonuclear leukocytes (PMNL) and caused marked improvement in the phagocytic property of the PMNL. This observation may have important clinical implications if this drug exerts a similar effect on other cells such as B cells. We examined [Ca2+]i, proliferation of B cells in response to mitogen, the magnitude of the PTH-induced inhibition of B cell proliferation, and the ATP content of mononuclear cells in 11 hemodialysis patients treated with nifedipine, 12 patients without nifedipine therapy and 11 normal subjects. Serum levels of IgG was also measured in the two groups of patients. There were no significant differences in the age, duration of hemodialysis, blood levels of calcium, phosphorus or PTH (571 +/- 193 vs. 484 +/- 127 pg/ml) among the two groups of patients. The hemodialysis patients without nifedipine therapy compared to those without nifedipine treatment have significantly (P < 0.01) higher levels of [Ca2+]i (120 +/- 1.9 nM vs. 94 +/- 2.2 nM), lower ATP content of mononuclear cells (0.45 +/- 0.06 nmol/10(6) cells vs. 0.68 +/- 0.04 nmoles/10(6) cells), impaired proliferation (5.8 +/- 0.31 x 10(3) cpm vs. 9.8 +/- 0.38 x 10(3) cpm) and smaller inhibition of B cell proliferation by PTH compared to those treated with nifedipine. The values in the patients treated with nifedipine were still modestly but significantly different than in normal subjects. The serum IgG levels of the patients without nifedipine therapy (1210 +/- 71 mg/dl) were significantly lower than those of the patients treated with nifedipine (1594 +/- 81 mg/dl). Thus, the treatment of hemodialysis patients with nifedipine produced marked and significant improvement in the metabolic and functional parameters of B cells despite no changes in blood levels of PTH. These data indicate that the calcium channel blocker, nifedipine, interferes with PTH-induced rise in [Ca2+]i of B cells of hemodialysis patients and consequently improves their metabolism and function. These observations if confirmed in other human cells may provide for a rational therapeutic approach to ameliorate the signs and symptoms of uremia.

Antigen phenotype and cytotoxic activity of natural killer cells in hemodialysis patients

The antigen phenotype and cytotoxic activity of peripheral blood natural killer (NK) cells have been studied in 35 patients on hemodialysis, evaluating the influence exerted by different types of dialysis membranes and diverse clinical and biologic features of end-stage renal disease. Two-color immunofluorescent analyses with different monoclonal antibodies and flow cytometry were performed to identify the NK cells. Functional cytotoxic assays were simultaneously performed in the same patients. The results show that hemodialysis elicits higher proportions of CD3−/CD56+ and CD3−CD16+ NK cells and a decrease in their cytotoxic activity compared with the control group. This alteration is related to the use of cuprophan membranes; biocompatible membranes would not significantly affect NK cells. The cuprophan membranes were also found to induce a higher degree of NK cell activation, measured as the number of CD16+/HLA-DR+ cells. Age appeared to be associated with NK cell function. Regarding age, in patients older than 65 years the change from cuprophan to biocompatible membranes was associated with a recovery in NK cytolytic activity to normal levels. In summary, hemodialysis with cuprophan membranes induces an increased proportion of both NK cells and activated NK cells associated with decreased NK cytolytic activity.

Lymphocyte subsets in hemodialysis patients treated with recombinant human erythropoietin

We investigated whether recombinant human erythropoietin (rhEPO) therapy affected the lymphocyte subsets in patients on long-term maintenance hemodialysis (HD) with severe anemia. Before treatment, the numbers of peripheral blood lymphocyte, CD3+, CD4+, CD8+, and CD20+ cells were decreased in HD patients compared to those in healthy subjects, while the number of CD3+HLA-DR+ cells was increased in HD patients compared to that in healthy subjects. Furthermore, the number of CD4+CD45RA+ (naive T) cells was markedly decreased in HD patients (112 +/- 77 vs 241 +/- 146/microliters; P < 0.01). The number of CD8+S6F1+ (cytotoxic T) cells in HD patients was also less than that in healthy subjects (247 +/- 104 vs 122 +/- 83/microliters; NS). During a 6-month period of rhEPO therapy, we found that the low level of CD4+CD45RA+ cells gradually increased (from 112 +/- 18 to 163 +/- 24/microliters; P < 0.01) with the elevation of hematocrit values (from 21.5 +/- 1.7 to 28.2 +/- 3.5%; P < 0.05). The number of CD3+HLA-DR+ cells decreased after 1 month of rhEPO therapy (from 93 +/- 14 to 46 +/- 13/microliters) and gradually declined throughout the 6-month study period. In our in vitro study, we demonstrated that no effects were observed on [3H]thymidine uptake in the T cell subsets at various concentrations of rhEPO. These results suggest that rhEPO-induced immunoregulation is mediated by an indirect stimulatory effect on the immune system, this stimulation being accompanied by an improvement in physical condition.

The response of peripheral blood mononuclear cells in hemodialysis patients to IFN-.GAMMA. using .BETA. 2-microglobulin production as an index.

The response of peripheral blood mononuclear cells in hemodialysis patients to IFN-.GAMMA. using .BETA. 2-microglobulin production as an index.

Defective Radioresistant Suppressor Cell Activity in Hemodialysis Patients

The immunologic alterations in patients on hemodialysis are only partially understood. We studied the Concanavalin A (Con A) induced suppressor cell activity of irradiated and nonirradiated cells in a mixed lymphocyte culture. Peripheral blood lymphocytes from 18 normal individuals and 14 patients on regular hemodialysis were incubated with two different concentrations of Con A (10 micrograms and 40 micrograms of Con A/million cells). Irradiated and nonirradiated cells were then tested for their capacity to suppress a standard MLC. The proliferative response to phytohemagglutinin, pokeweed mitogen and Con A was also determined. Suppressor cell activity of nonirradiated cells in hemodialysis patients was similar to that of controls, at both concentrations of Con A, while irradiated cells of hemodialysis patients showed a suppressor cell activity significantly lower than that of the controls, at a Con A concentration of 40 micrograms/10(6) cells (25.78 +/- 18.86% vs. 46.05 +/- 9.79%, p less than 0.001). The proliferative response of lymphocytes from hemodialysis patients to the three mitogens, did not show any difference when compared with normal controls. The normal proliferative response of lymphocytes from hemodialysis patients to mitogens and the normal suppressor cell activity of nonirradiated cells, suggest a normal T cell function. The abnormal suppressor cell activity in irradiated cells indicate that the radioresistant population has a functional defect. The cell responsible for this suppressor defect probably belongs to the monocyte/macrophage population because of its relative radioresistance.