Quantitative and functional characteristics of endothelial progenitor cells in newly diagnosed hypertensive patients.

Populations of peripheral blood CD34(+) cells comprise precursors of endothelial cells. These precursors are crucial to cardiovascular homeostasis. Hypertension, as one of the main risk factors for cardiovascular disease, is associated with the loss of endothelium structural integrity and its functional impairment. The aim of our study was to evaluate the subsets of endothelial precursor cells in patients with newly diagnosed arterial hypertension. Twenty-four newly diagnosed, previously untreated hypertensive patients aged 59.5 ± 12.5 years, were enrolled into the study group, whereas the control group comprised 45 healthy subjects, 55.5±10.0 years old. Endothelial progenitor cells (EPCs) were analysed by flow cytometry. The results showed that hypertensive patients were characterized by a significantly higher percentage and number of the CD34(+) cells and simultaneously less differentiated CD34(+)CD45(dim/neg)CD133(+) progenitors. The percentage and number of CD34(+)CD45(neg)VEGFR2(+) and CD34(+)CD45(neg)CD133(+)VEGFR2(+) cells were not different from the control group. Moreover, patients had a significantly lower percentage and number of the CD34(+)CD45(neg)VEGFR2(+)CXCR4(+) and CD34(+)CD45(neg)VEGFR2(+)ICAM-1(+) cells than healthy individuals. These changes were paralleled by early symptoms of nephropathy, that is, lower glomerular filtration rate (GFR) values and borderline micro albuminuria. Our results indicate that an elevation in the number of less differentiated progenitors may be a mechanism compensating for defects of migration and adhesion, present in a more differentiated subset.

Association between vascular endothelial growth factor and hypertension in children and adolescents type I diabetes mellitus.

The aim of the study was to analyse the relationship between the serum level of vascular endothelial growth factor (VEGF) and the incidence of hypertension (HT) in children and adolescents with type I diabetes mellitus (T1DM). One hundred and five patients with T1DM were enrolled in the study. The control group consisted of 30 healthy controls. All the T1DM patients were subjected to biochemical analyses, ophthalmologic examination and 24-h blood pressure monitoring. Besides, all the patients and healthy controls had serum VEGF levels measured with the use of the ELISA methodology. The essence of our research is that patients with T1DM and HT and with microalbuminuria (MA) and diabetic retinopathy (DR) (MA/DR) are characterized by a significantly higher level of VEGF (340.23±93.22 pg ml(-1)) in blood serum in comparison with the group of T1DM patients without HT and MA/DR (183.6±96.6 pg ml(-1)) and with healthy controls (145.32±75.58 pg ml(-1)). In addition, the VEGF level was significantly higher in T1DM patients, who presented all three complications, that is HT, retinopathy and MA in comparison with T1DM patients without HT, but with MA/DR (P=0.036). On the other hand, no statistically significant differences (P=0.19) were noted in the level of VEGF in serum between T1DM patients without HT and MA/DR and the healthy control group. At a further stage of analysis, using the method of multiple regression, it was shown that systolic pressure, HbA1c and duration of disease are independent factors influencing the concentration of VEGF. Summarizing, the measurement of VEGF serum levels allows for the identification of groups of patients who have the highest risk of HT and, subsequently, progression of vascular complications.

Interleukin-12 and tumour necrosis factor-alpha equilibrium is a prerequisite for clinical course free from late complications in children with type 1 diabetes mellitus.

The objective of the study was to analyse levels of IL-12 and TNF-alpha and relate the findings to the occurrence of microangiopathy in children with type 1 diabetes mellitus (DM). We examined a group of 123 children with type 1 DM. Serum levels of IL-12 and TNF-alpha were measured by an immunoenzymatic ELISA technique. TNF-alpha and IL-12 tended to be simultaneously present or absent in the sera of 50% of the children who had not developed complications, thus indicating a state of cytokine's equilibrium. Among the patients with an established retinopathy, two IL-12/TNF-alpha combinations were visible. Either a lack of detectable TNF-alpha was accompanied by measurable IL-12 serum concentrations or TNF-alpha incidence was associated with undetectable IL-12 values. Simultaneous lack of TNF-alpha and presence of IL-12 was associated with a better prognosis as these patients had a significantly lower albumin excretion rate. The state of equilibrium between TNF-alpha and IL-12 is beneficial in patients at early stages of the disease, prior to the occurrence of complications. Shifting the equilibrium towards TNF-alpha seems to promote late complications. It may suggest that a disharmony between pro- and anti-angiogenic function of these cytokines underlie the mechanism by which TNF-alpha and IL-12 shape the disease course.

Successful ageing of nonagenarians is related to the sensitivity of NK cells to activation.

NK cells are a component of innate immunity which activity significantly correlates with health status. The aim of our study was to estimate a status of NK (natural killer) cells in the very old (mean age 92+/-2 ys) and old subjects (mean age 78+/-5 ys) as compared to a control group of young individuals (mean age 25+/-4 ys). NK cells were characterized by measurement of their cytotoxic activity, expression of intracellular interferon gamma, telomere length and telomerase activity in resting and activated cells. The results revealed that the oldest seniors did not differ from the other age groups in the number of NK cells and NK cytotoxic activity, however, they displayed the shortest telomeres and the lowest telomerase activity. Surprisingly, activated NK cells of the very old, similarly to the old subjects, were able to significantly increase intracellular level of IFNgamma. Moreover, activated with IL-2 NK cells of the old and oldest seniors showed increased telomerase activity. The results of our study suggest that the functional status of NK cells and their sensitivity to activation is well preserved until very advanced age and may contribute to longevity and successful ageing.

Natural killer cell activity unaffected by ozonated autohemotherapy in patients with end-stage renal disease on maintenance renal replacement therapy.

Ozonotherapy is a complementary medical approach in the treatment of resistant infections, immune deficiency syndromes, orthopedic pathologies and vascular diseases. The criticism of this method is associated with potentially harmful effects of ozone on cells. The aim of this study was to investigate the influence of ozonated autohemotherapy (O3-AHT) on the cellular response of the immunologic system represented by cytotoxic activity of natural killer cells. 12 hemodialyzed patients (8 M, 4 F) aged 64.8 +/- 7.6 years with peripheral arterial disease as the main reason for the treatment with O3-AHT were examined in a prospective, placebo controlled, single blind study. They received 9 sessions of autohemotherapy without ozone exposure as a placebo-control and subsequent 9 sessions of O3-AHT. The procedures were performed 3 times a week, just before hemodialysis session. Ozone-oxygen gas mixture with ozone concentration of 50 microg/ml produced by ozone generator (ATO3, KrioMetrum, Poland) was used during O3-AHT Natural killer cell activity was measured using lactate dehydrogenase release assay There was no statistical difference between natural killer cell activity (%) at the baseline (16.78 +/- 8.07), after nine sessions of control autohemotherapy (15.98 +/- 6.67), and after nine sessions of O3-AHT (18.26 +/- 8.82). In conclusion, our findings showed that O3-AHT in a dose of 50 mg/mL does not have any significant influence on natural killer cell function in hemodialyzed patients.

Immunomodulating effect of influenza vaccination in the elderly differing in health status.

The aim of this study was to analyse whether split influenza vaccine may elicit NK cytotoxic response in the vaccinated elderly people and whether this effect may be maintained over few weeks after vaccination. It was also worth investigating the relation between NK activity in the vaccinated and specific immune protection against influenza and non-specific against other infections. Two groups of volunteers were vaccinated with trivalent split viron influenza vaccine in two consecutive seasons (1999/2000; 2000/2001). The elderly group consisted of 142 people (65-92 years old) in the first season and 110 in the second; while the young (16-44 years old) of 98 and 67 people, respectively. An analysis of NK cytotoxic activity had been done before vaccination, two days, one month and fifth months thereafter. The results revealed that vaccination with the influenza vaccine had an augmenting effect on NK activity, in all groups examined, in both epidemic seasons, visible at two days and 1 month after the vaccination. In the elderly high pre- and post-vaccination NK activity was related to higher titers of anti-hemagglutinin, better health status and lower incidence of all cause respiratory tract infections. At the second vaccination, most of the elderly with chronic medical conditions and high NK activity, who did not attain the protective level of anti-hemagglutinins in the first season, converted into the protected. High pre- and post-vaccination NK activity predisposes elderly people to the protective humoral anti-hemagglutinin response and gives better protection from respiratory tract infections.

Serum interleukin-6 levels and bone mineral density at the femoral neck in post-menopausal women with Type 1 diabetes.

BACKGROUND: Although osteopenia is often reported in Type 1 diabetes mellitus, the pathogenic mechanisms are not fully understood. Oestrogen deficiency also leads to decreased bone mineral density (BMD). Enhanced interleukin-6 (IL-6) production among Type 1 diabetic patients could be involved in the pathogenesis of diabetic bone loss since it is a potent bone resorbing cytokine. AIMS: To evaluate the relationship between serum bioactive IL-6 levels and BMD at the femoral neck of post-menopausal women with Type 1 diabetes. METHODS: We studied BMD, urine excretion of deoxypirydynoline crosslinks, serum bioactive IL-6 and soluble IL-6 receptor (sIL-6R) levels in 20 post-menopausal women with Type 1 diabetes mellitus, and compared these results with 20 matched healthy post-menopausal controls. RESULTS: Post-menopausal women with Type 1 diabetes had significantly lower BMD at the femoral neck and increased serum bioactive IL-6 levels compared with the control group, but no relationship was observed between these variables in a multiple regression analysis. Using BMD at the femoral neck of diabetic women as the dependent variable in the multiple step regression analysis model, we found that independent variables that were strongly associated with bone mass at the femoral neck in this group were: time since menopause and duration of diabetes. CONCLUSIONS: Although our study had a small sample size, we found that post-menopausal women with Type 1 diabetes mellitus present lower bone mass and higher serum bioactive IL-6 levels than matched healthy controls, but we were unable to find a correlation between these two parameters.

Effects of oestrogen deprivation on interleukin-6 production by peripheral blood mononuclear cells of postmenopausal women.

Various hormones can influence the expression of interleukin-6 (IL-6) and oestrogens are the most extensively studied. There is, however, controversy about the nature of the IL-6 secreted by human cells and its regulation by 17beta-oestradiol. The aim of this work was to clarify whether oestrogen deprivation after menopause may contribute to an enhanced IL-6 production by peripheral blood mononuclear cells (PBMC) in postmenopausal women. Twenty-two healthy postmenopausal women, age range 45-63 years, with clinical symptoms of oestrogen deficiency were enrolled in the study. The control group consisted of 16 healthy young women, age range 22-31 years, with regular menses and who were not taking oral contraceptives. Levels of IL-6 in the sera and PBMC culture supernatants were measured by the biological B9 cell-proliferation assay and expression of the IL-6 gene in non-stimulated PBMC was detected by RT-PCR. The effect of 17beta-oestradiol on spontaneous IL-6 production by the PBMC of postmenopausal women was also studied in vitro and in vivo. Seventeen out of the twenty-two postmenopausal women were given hormonal replacement therapy of 50 microg 17beta-oestradiol/day transdermally and the spontaneous production of IL-6 by the PBMC was analysed after 6 and 12 months of treatment. The postmenopausal women had significantly higher serum levels of IL-6 than the young controls. The spontaneous production of IL-6 by non-stimulated PBMC into the culture supernatants was also significantly higher in the postmenopausal women compared with the young. We also found that IL-6 gene expression was present in the non-stimulated PBMC isolated directly from the venous blood of the majority of the postmenopausal women. Women with IL-6 gene expression in the non-stimulated PBMC had significantly lower serum levels of 17beta-oestradiol compared with those where the IL-6 gene was not expressed in the PBMC. Our in vitro experiments showed that 17beta-oestradiol at concentrations of 10(-9) M and 10(-10) M decreased spontaneous IL-6 production by the PBMC of postmenopausal women. In vivo treatment with 17beta-oestradiol transdermally also significantly decreased spontaneous IL-6 production by the PBMC of postmenopausal women after 12 months of the therapy. Our results indicate that oestrogen deprivation after menopause may enhance IL-6 production by the PBMC of postmenopausal women. We suspect that the late complications of oestrogen deficiency, such as osteoporosis, coronary heart disease and Alzheimer's disease, may be mediated by an exaggerated production of IL-6 - a cytokine which seems to play a pivotal role in the pathogenesis of these age-related diseases.

Natural killer activity and thyroid hormone levels in young and elderly persons.

BACKGROUND: On the basis that (1) multiple interactions exist between the hormonal and immune systems, and (2) aging is accompanied by changes in thyroid hormone metabolism and responsiveness, we postulate that thyroid hormones may be involved in the observed decrease in natural killer (NK) activity in a population of apparently healthy elderly subjects. The purpose of the study is to compare NK cytotoxic activity and serum concentrations of TSH and thyroid hormones in healthy old and young people, and to assess in vitro the effects of triiodothyronine (T(3)) on NK activity. MATERIALS AND METHODS: Sixteen of the 47 healthy old people (mean age 64 +/- 5.2) were classified as optimally healthy, and the remainder as 'almost healthy' (according to the criteria of the Senieur protocol) [Ligthart et al., Mech Ageing Dev 1984;28:47-55]; the mean age of the healthy young people was 23.3 +/- 2.3 years. NK cytotoxic activity of peripheral blood mononuclear cells was assessed using (51)Cr release from K562 target cells. The cutoff level for defining low and high NK responses was set at a value of 20%. Serum concentrations of TSH, total thyroxine (T(4)) and total triiodothyronine (T(3)) were measured by radioimmunoassay. RESULTS: NK activity in the 'optimally healthy' elderly was high (mean 41 +/- 12%, SE), whereas 'almost healthy' subjects showed low NK activity (mean 6 +/- 5%). Serum T(4) and TSH levels, but not T(3) concentrations were similar in both the young and old. We observed a significant correlation (r = 0.53, n = 21, p < 0.05) between the serum total T(3) level and the NK activity in the elderly individuals. Under in vitro conditions exogenous T(3) significantly increased NK activity in the elderly subjects who had serum T(3) values at the lower end of the reference range. However, no effect of T(3) on NK activity was observed in peripheral blood mononuclear cells obtained from either old or young individuals who had serum T(3) levels at the midpoint of the range. CONCLUSION: Decreased serum concentrations of total T(3) may contribute to low NK activity in the 'almost healthy' subgroup of the elderly.

Luteal phase of the menstrual cycle in young healthy women is associated with decline in interleukin 2 levels.

The aim of this study was to look at the possible changes in the blood levels of Interleukin 2 (IL2) during the sexual cycle in generally healthy, young, regularly menstruating women. The concentrations of progesterone and 17beta-estradiol were measured using radioimmunological assay. The bioactivity of interleukin 2 was measured using a biological test on the IL2-sensitive CTLL cell line. The percentage of lymphocytes with intracellular IL2 was determined by flow cytometry. Eighteen healthy volunteers (19-29 years old) were examined on days 5, 8, 14, 18 and 25 of the same cycle. All women were characterised by a regular menstrual cycle as per physiological levels of 17beta-es-tradiol and progesterone. The luteal phase of the cycle was characterised by both a decrease of IL2 blood levels and a decrease in the percentage of intracellular 1L2-containing lymphocytes stimulated in vitro. The IL2 level fluctuations observed during the menstrual cycle may be one factor causing pre-menstrual infections observed in young women. On the other hand, the decrease of IL2 may be seen as a start of the immune suppression necessary for an embryo's nidation.

Lower interleukin-2 and higher serum tumor necrosis factor-a levels are associated with perimenstrual, recurrent, facial Herpes simplex infection in young women.

The aim of this study was to look at a possible relationship between the recurrent perimenstrual dermatosis - facial Herpes simplex infection and the serum concentrations of interleukin-2 (IL-2) and tumor necrosis factor alpha (TNF-alpha). Twenty-one volunteers (19-26 year olds) were examined at five points of the menstrual cycle. Ten volunteers were characterised by recurrent Herpes simplex infection lasting either from the 18th or the 25th day of the menstrual cycle until a few days after menstruation. Eleven young women without symptoms formed the control group. Both groups were similar as regards blood levels of 17beta-estradiol and progesterone. The group with the frequent infectious symptoms was characterised, however, by lower concentrations of IL-2 throughout the whole menstrual cycle, as compared to those without the symptoms. Levels of IL-2 in this group additionally dropped significantly on the 18th and on 25th day of the cycle. Moreover, the group with symptoms was characterised by higher level of TNF-alpha on the 18th day. These changes were found during the menstrual cycle of the women with recurrent herpes infection who however, at the time of the examination were free of the clinical symptoms. There was a similar tendency in both groups towards an increase in the levels of TNF-a around menstruation. Measurement of the other serum pro-inflammatory marker - IL-6 showed higher levels of this cytokine during the menstrual cycle in the group with the clinical symptoms. The results indicate that a decrease of IL-2 together with an increase of TNF-alpha and IL-6 in the serum seem to be related to recurrent perimenstrual Herpes simplex infection.

Compensatory effect of TNFalpha on low natural killer activity in the elderly.

Regulatory effect of CD25, an activation antigen the alpha subunit of interleukin 2 receptor (IL2R) on the activity of natural killer (NK) cells was studied in fifty elderly (57-70 years old) and fifty young people (19-35 years old). Cytotoxic NK activity was assessed by 51Cr release assay, the levels of interleukin 2 (IL2) and tumour necrosis factors alpha (TNFalpha) were measured using bioassays and expression of CD16 and CD25 proteins by flow cytometry. Low NK activity in the elderly was associated with decline of full health, lowered serum concentration of IL2 and increased production of TNFalpha during NK reaction. Inhibition of TNFalpha activity by anti-TNF monoclonal antibody suppressed exclusively NK activity of low NK responders. Moreover, stimulation in vitro of blood mononuclear cells, with TNFalpha induced in the elderly low NK responders a significantly higher increase of the CD25 expression on the surface of NK cells as compared with that in the elderly high responders. Since the CD25 molecule constitutes a subunit of the high affinity receptor, binding IL2 to immunocompetent cells, its increased expression on NK cells of low NK responders would enable them to bind even low amounts of the endogenous IL2 available in this group of the elderly. Thus, an overproduction of TNFalpha seems to be a mechanism compensating, in the non-fully healthy elderly, for the decreased IL2 production, promoting efficient cytotoxic reaction.

Recombinant human erythropoietin stimulates production of interleukin 2 by whole blood cell cultures of hemodialysis patients.

The impairment of function of human T lymphocytes, leading to an inappropriate cytokine production, is partially responsible for defective immunological response in hemodialysis patients (HD). Recent data suggest that recombinant human erythropoietin (rhEPO) may exert immunological effects. The aim of this study was to find out whether rhEPO treatment of the HD patients may have an effect on the interleukin 2 (IL-2) production by their whole blood cell cultures. The study was carried out in 10 HD patients receiving rhEPO for 6 months. Compared with the levels seen before the treatment, the concentration of IL-2 increased in the phytohemagglutinin-stimulated whole blood cell cultures of 7 of 10 patients under study. Addition of rhEPO in vitro to the whole blood cell cultures of the HD patients before implementation of erythropoietin confirmed that rhEPO is able to directly stimulate IL-2 production. Our studies show that the therapy with rhEPO affects IL-2 secretion.

Nitric oxide, heparin and procaine treatment in experimental ceruleine-induced acute pancreatitis in rats.

The aim of the study was to investigate the impact of L-arginine (nitric oxide donor), L-NNA (NO synthase inhibitor), heparin and procaine on the pancreas' microcirculation, serum interleukin 6 (IL-6) level, and microscopic alterations of the pancreatic gland in acute pancreatitis (AP) in rats. AP was induced by 4 i.p. injections of cerulein (15 micrograms/kg/h). Microcirculatory values of the pancreas were measured by means of laser Doppler flowmetry 5 h after the first cerulein injection. Remarkable morphologic changes in the pancreas, including parenchymal necrosis, an elevation of serum IL-6 activity, and significant drop of pancreatic capillary perfusion was observed in rats with NO synthase inhibition. L-arginine improved the pancreatic microcirculation but worsened the microscopic alterations within the pancreas. Heparin had a beneficial effect on the microcirculatory values, serum IL-6 activity, and morphologic changes. Procaine had no effect on the course of AP. Authors conclude that heparin, improving the pancreatic capillary blood perfusion, may be considered as a promising therapeutic agent in acute pancreatitis.

The upregulation of TNF alpha production is not a generalised phenomenon in the elderly between their sixth and seventh decades of life.

The aim of this paper was to analyse the link between the intensity of tumor necrosis factor alpha (TNF alpha) production and the health status of the elderly and to find out whether the age between sixty and seventy is a 'turning point' for the changes in the production of this cytokine. Fifty elderly volunteers (age range: 60-70), twenty-five middle-aged (age range: 36-59) and fifty young (age range: 20-35) were enrolled into the study. Their health status was graded as 'healthy' and 'almost-healthy'. The level of TNF alpha was determined by bioassay, the activity of the TNF alpha gene was analysed in non-stimulated PBMC by the RT-PCR method. The results showed that the production of TNF alpha in the 'healthy' elderly people is not upregulated until the age of sixty-seventy. The 'almost-healthy' elderly are characterised by a higher release of TNF alpha from the cultures of non- and stimulated PBMC and an activation of the TNF alpha gene in the non-stimulated PBMC. Summarising, our results indicate that the deterioration of health status is a prerequisite for an exaggerated TNF alpha production by peripheral blood mononuclear cells of people between the sixth and seventh decades of life.

Heparin and nitric oxide treatment in experimental acute pancreatitis in rats.

The aim of this study was to investigate the impact of L-arginine (nitric oxide synthase substrate), L-NG-nitro-L-arginine (nitric oxide synthase inhibitor), and heparin on the pancreas microcirculation, serum IL-6 level and microscopic alterations of the pancreas in acute pancreatitis in rats. Acute pancreatitis was induced by 4 i.p. injections of cerulein (15mg/kg). Microcirculatory values were measured by means of laser Doppler flowmetry 5 h after the first cerulein injection. Remarkable histopathological changes in the pancreas, including parenchymal necrosis, an elevation of serum IL-6 level, and a significant drop of pancreatic capillary perfusion was observed in rats with nitric oxide synthase inhibition. L-arginine improved the pancreatic microcirculation but worsened the microscopic alterations within the pancreas. Heparin had a beneficial effect on the microcirculatory values, serum IL-6 concentration, and morphologic changes. Authors conclude that inhibition of nitric oxide synthase aggravates acute pancreatitis. L-arginine treatment improves pancreatic perfusion but potentiates morphological alterations. Heparin, improving the microcirculation and inflammatory changes within the pancreatic gland, may be considered as a promising therapeutic agent in acute pancreatitis.

Increase of interleukin 6 and decrease of interleukin 2 production during the ageing process are influenced by the health status.

The ageing process is accompanied by the disregulation of interleukin 2 (IL2) and interleukin 6 (IL6) production. In our paper, we asked whether the age between 60 and 70 years is a turning point for the disregulation of both IL2 and IL6 production. Fifty volunteers 60-70 years old, 25 aged 36-59, and 50 of 20-35 years old were enrolled into the study. Their health status was graded according to the criteria of the Senieur Protocol (SP) as 'healthy' and 'almost-healthy'. The cytokines level was determined in the sera of the volunteers. Moreover, the spontaneous release of IL6 by peripheral blood mononuclear cells (PBMC) and the activity of the IL6 gene in non-stimulated PBMC were also analysed. Cytokine levels were measured by biological assays, mRNA for IL6 was detected by RT-PCR method. The results showed that the production of IL2 is not disregulated in the 'healthy' people until the age of 60-70. People not fulfilling all SP criteria are characterised by a lower level of IL2 in the sera. The overproduction of IL6 into the sera and supernatants from non-stimulated PBMC and PBL as well as the activation of IL6 gene start between the ages 36 and 59 and is more pronounced in the 'almost-healthy'.

Significance of tumor necrosis factor alpha in patients with long-standing type-I diabetes mellitus.

Fifteen out of the forty-five patients with long-standing diabetes mellitus type I were characterised by the presence of TNFalpha in the sera when examined on several occasions over a period of five years. TNFalpha-producing patients had a better control of the disease and a smaller percentage of them suffered from diabetic complications as compared with those not producing this cytokine. TNFalpha-producing patients had lower levels of the proinflammatory markers - IL6 and CRP, and higher concentrations of ACTH and cortisol than those not producing this cytokine. We suggest that TNFalpha released systemically in diabetic patients stimulates the hypophysis-adrenal axis, and in that way indirectly ameliorates autoimmune response occurring during the advanced phase of the disease.

The influence of recombinant human erythropoietin on tumor necrosis factor alpha and interleukin-10 production by whole blood cell cultures in hemodialysis patients.

Impaired immunological response in hemodialysis (HD) patients, which leads to inappropriate cytokine production, is partially caused by the hyperstimulation of both T lymphocytes and monocytes/macrophages. Recent data suggest that human recombinant erythropoietin (rhEPO) may have an immunological action. The goal of our study was to estimate the influence of rhEPO treatment on the production of the inflammatory cytokine tumor necrosis factor alpha (TNFalpha) and antiinflammatory cytokin interleukin-10 (IL-10) in 10 HD patients receiving rhEPO for 6 months. The levels of cytokines were measured in the in vitro cultures of whole blood. The level of IL-10 increased in all treated patients during the therapy, and it was accompanied by a transitory decrease of TNFalpha. The results of our studies suggest that rhEPO may reduce the inflammatory process by decreasing production of TNFalpha and increasing production of IL-10.