Systemically administered interleukin-10 reduces tumor necrosis factor-alpha production and significantly improves functional recovery following traumatic spinal cord injury in rats.

In these studies, we examined the neuroprotective effects of the potent antiinflammatory cytokine interleukin-10 (IL-10) following spinal cord injury (SCI). Neuroprotection was assessed by using behavioral and morphological end points. We hypothesized that injury-induced inflammation contributes to the resulting neuropathology and subsequent loss of function. Therefore, by attenuating injury-induced inflammation, we should promote functional recovery. The New York University device was used to induce moderate SCI and study the resulting inflammatory response and functional consequences of inhibiting this response in rats. We determined that SCI induces the expression of tumor necrosis factor-alpha (TNF-alpha) in the spinal cord and by SCI-activated monocytes isolated from the peripheral circulation. IL-10 (5.0 microg) administered 30 minutes after-injury significantly reduced the expression of TNF-alpha protein in the spinal cord and in vitro by SCI-activated monocytes. Next, we investigated whether IL-10 would improve functional recovery after SCI. Randomized, double-blinded studies demonstrated that a single injection of IL-10 significantly improves hind limb motor function 2 months after injury, as determined by the Basso, Beattie and Bresnahan (BBB) open-field behavioral test. IL-10-treated animals had a mean BBB score of 18.0+/-0.5 (SEM, n = 9) compared with a score of 12.9+/-0.6 (SEM, n = 9) for the saline-treated controls. Morphological analysis demonstrated that IL-10 reduces lesion volume by approximately 49% 2 months after injury. These data suggest that acute administration of IL-10 reduces TNF-alpha synthesis in the spinal cord and by activated macrophages, is neuroprotective, and promotes functional recovery following SCI.     

beta(2)-Microglobulin modified with advanced glycation end products delays monocyte apoptosis

BACKGROUND: A local inflammatory reaction to beta(2)-microglobulin (beta(2)m) amyloid deposits by monocytes/macrophages is a characteristic histologic feature of dialysis-related amyloidosis (DRA). Since beta(2)m modified with advanced glycation end products (AGE-beta(2)m) is a major constituent of amyloid in DRA, we tested the hypothesis that AGE-beta(2)m affects apoptosis and phenotype of human monocytes. METHODS: Human peripheral blood monocytes were incubated with or without in vitro-derived AGE-beta(2)m, and their viability, extent of apoptosis, morphology, and function examined over the subsequent four days. RESULTS: AGE-modified but not unmodified beta(2)m significantly delayed spontaneous apoptosis of human peripheral blood monocytes in adherent and nonadherent cultures. The effect of AGE-beta(2)m on monocytes apoptosis was time- and dose-dependent and was attenuated by a blocking antibody directed against the human AGE receptor (RAGE). There was no difference in effect between AGE-beta(2)m and that of AGE-modified human serum albumin. Culture of monocytes with AGE-beta(2)m did not alter membrane expression of Fas or Fas ligand. Monocytes cultured with AGE-beta(2)m underwent substantial changes in morphology similar to those observed when monocytes differentiate into macrophages. The cultured cells increased in size and vacuolization, and their content of beta-glucuronidase and acid phosphatase increased by 5- to 10-fold at day 4. Expression of the monocyte--macrophage membrane antigens HLA-DR, CD11b, and CD11c also increased at day 4. Although exhibiting phenotypic characteristics of macrophages, monocytes cultured with AGE-beta(2)m functioned differently than macrophages cultured with serum. Superoxide production in response to phorbol myristic acetate was maintained in monocytes cultured with AGE-beta(2)m, but declined with time in cells cultured with serum. Constitutive synthesis of tumor necrosis factor-alpha (TNF-alpha), interleukin-1 beta (IL-1 beta) and prostaglandin E2 (PGE2) increased in monocytes cultured for four to six days with AGE-beta(2)m. CONCLUSIONS: These findings support a novel role for AGE-modified proteins such as AGE-beta(2)m that may contribute to the development of a local inflammatory response, with predominant accumulation of monocytes/macrophages, in DRA.     

Effect of interleukin-10 on human anti-porcine xenogeneic cellular response in vitro

BACKGROUND: Pigs are being used as an alternative source of tissues for humans and we are interested in the xenotransplantation of fetal pig islet-like cell clusters (ICC) into type 1 diabetic patients. Interleukin-(IL) 10 is a Th2 cytokine with immunosuppressive properties that down-regulate the cell-mediated response. In this study, we evaluated the effects of recombinant human IL-10 on human anti-pig xenogeneic cellular response in mixed lymphocyte culture (MLC) and in mixed islet lymphocyte culture (MILC). METHODS: Human peripheral blood mononuclear cells as responder cells were cultured in one-way MLC with pig and human peripheral blood mononuclear cells as stimulant cells in xeno and allo-MLC, respectively, and also with fetal pig ICCs in MILC. IL-10 was added at the time of culture. RESULTS: The addition of IL-10 significantly inhibited the xeno-MLC (human anti-pig) in a dose-dependent manner, the percentage inhibition being 36, 60, and 73% at 1, 10, and 50 ng/ml, respectively. Inhibition in xeno-MLC was significantly lower than that of the allo-MLC (human anti-human) at all concentrations used, the percentage inhibition of the latter being 58, 84, and 92% at 1, 10, and 50 ng/ml, respectively. Further, the addition of IL-10 also significantly inhibited the proliferation of human peripheral blood mononuclear cells when they were cocultured with fetal pig ICCs, the inhibition being 59, 72, and 80% at 1, 10, and 50 ng/ml, respectively. IL-10 was not toxic to ICCs as determined by 3H-thymidine incorporation over 5 days culture. Preincubation of IL-10 with the pig stimulant cells or the human responder cells did not confer additional benefit in the inhibition of xeno-MLC. IL-10 needs to be present at the start or at an early stage (within 4 hr) in the xeno-MLC because if the addition of IL-10 was delayed by 4 hr, the effect was lost. Next, the production of cytokines was examined in MLC and MILC. In xeno-MLC, levels (pg/ml) of tumor necrosis factor-alpha (TNF-alpha) (163+/-17), interferon-gamma (IFN-gamma) (278+/-60), IL-5 (24+/-10), IL-6 (2959+/-923), and IL-10 (17+/-2) were produced in greater amounts than autologous controls (P<0.05). The levels of TNF-alpha, IFN-gamma, IL-6, and IL-10 but not IL-5 were significantly (P<0.05) lower in xeno-MLC than those produced in allo-MLC. All of these cytokines were also produced in MILC when human peripheral blood mononuclear cells (PBMC) were cocultured with ICCs, levels (pg/ml) being TNF-alpha (308+/-47), IFN-gamma (93+/-17), IL-5 (6.2+/-3), IL-6 (5649+/-421), and IL-10 (122+/-18). No detectable levels of IL-2 and IL-4 were produced in the MLC and in MILC. Addition of IL-10 significantly inhibited the production of TNF-alpha, IFN-gamma, IL-5, and IL-6 by 76, 96, 100, and 93%, respectively, in xeno-MLC. Addition of IL-10 also significantly (P<0.05) inhibited the production of TNF-alpha, IFN-gamma, IL-5, and IL-6 by 88, 91, 100, and 96%, respectively, in MILC. Exogenous addition of IL-2 was partially able to reverse the effect of IL-10 although addition of TNF-alpha had no effect on xeno and allo-MLC. Synergism was seen between IL-10 and cyclosporine in the inhibition of xeno and allo-MLC. CONCLUSION: Taken together, the results demonstrated that IL-10 has an immunomodulatory role to play in the inhibition of cellular immune responses associated with the xenotransplantation of fetal pig ICCs.     

Increased interleukin-13 expression in patients with sarcoidosis

BACKGROUND: Sarcoidosis is a systemic granulomatous disorder of unknown origin. Lymphocytic inflammation is dominated by expression of Th1 type cytokines such as tumour necrosis factor alpha (TNFalpha). Interleukin 13 (IL-13) is a Th2 cytokine which is expressed by CD4+ T cells and has been shown to suppress TNFalpha in human blood monocytes. The role of IL-13 as a possible anti-inflammatory cytokine in sarcoidosis was investigated. METHODS: mRNA expression of IL-13, IL-4, IL-10, and TNFalpha in bronchoalveolar lavage (BAL) fluid cells and peripheral mononuclear blood cells (PBM) of 18 patients with sarcoidosis and nine healthy controls was assessed using RT-PCR. In addition, IL-13 protein levels in BAL cell culture supernatants from 12 patients and all controls were measured and immunocytochemistry of IL-13 protein was performed in BAL fluid cells of eight patients. TNFalpha concentrations were measured with and without stimulation with recombinant human (rh) IL-13, rhIL-10, and lipopolysaccharide (LPS). RESULTS: IL-13 mRNA expression was significantly increased in BAL cells and PBM of patients compared with controls (p<0.05). No significant difference was found in IL-4 mRNA or IL-10 mRNA expression in BAL fluid cells or PBM between the two groups. TNFalpha mRNA expression was significantly higher in BAL fluid cells of patients than controls (p<0.05). IL-13 protein levels in BAL cell culture supernatants were slightly raised in half the patients investigated but in only two controls. Immunocytochemistry detected IL-13 protein in alveolar macrophages of patients. IL-13 led to decreased TNFalpha concentrations (p<0.05). CONCLUSIONS: IL-13 expression is increased in BAL cells and PBM in sarcoidosis and IL-13 is secreted from BAL cells. Alveolar macrophages may be the cellular source. These data suggest that IL-13 might have an anti-inflammatory effect by acting on TNFalpha.     

Distinct regulation of IL-8 and MCP-1 by LPS and interferon-&ggr;-treated human peritoneal macrophages

Background: Interleukin-8 and monocyte chemotactic protein-1 (MCP-1) are major leukocyte chemoattractants during bacterial peritonitis by recruiting neutrophils and monocytes/macrophages respectively. Methods: Peritoneal macrophages (PM) from 12 different CAPD patients with peritonitis were stimulated with either 10 ng/ml LPS, 10 ng/ml IFN-&ggr; or LPS+IFN-&ggr;, and IL-8 and MCP-1 production was determined on protein and mRNA levels by using ELISA technique and Northern blot analysis. To obtain information from two different stages of activation, experiments were done with highly activated PM directly after isolation and with cells after 10 days in culture, each group being stimulated for 4 h. Unstimulated cells served as control. Results: Immediately after isolation IL-8 mRNA-expression and synthesis was high and could be further increased by LPS stimulation, whereas IFN-&ggr; treatment showed no significant influence. The levels of MCP-1 were also initially high but could not be further stimulated by LPS, whereas addition of IFN-&ggr; resulted in a significant rise in MCP-1 synthesis. After 10 days in culture LPS-stimulation of cells again revealed a significant increase in IL-8 protein synthesis, whereas IFN-&ggr; showed no effect. LPS anergy for MCP-1 was still seen in PM after 10 days in culture, and IFN-&ggr; treatment again induced a significant rise in MCP-1 synthesis. The overall production of both chemokines was far higher on day 1 compared to day 10. Conclusion: Our data show differences in LPS/IFN-&ggr; regulation for IL-8 and MCP-1 in both highly activated and in resting, mature peritoneal macrophages, suggesting distinct pathways for these chemokines that may offer a means of control for the specific recruitment of neutrophils and monocytes/macrophages in bacterial peritonitis.     

Relative production of tumour necrosis factor alpha and interleukin 10 in adult respiratory distress syndrome

BACKGROUND: The adult respiratory distress syndrome (ARDS) may be regarded as an example of an uncontrolled or excessive inflammatory response in which tumour necrosis factor alpha (TNF-alpha) has been proposed to play a central role. Interleukin 10 (IL-10) has been identified as an important regulator of this response. The potential role for IL-10 in this context was investigated by measuring the relative production of IL-10 and TNF-alpha protein in the plasma, bronchoalveolar lavage (BAL) fluid, and alveolar macrophage culture supernatants of patients with, or at risk of developing, ARDS. METHODS: Twenty six patients were studied from three groups at risk of or with ARDS: sepsis (n = 12), multiple trauma (n = 8), and perforated bowel (n = 6). Ten patients had ARDS. Bronchoalveolar lavage and venepuncture were performed within 24 hours of arrival on the intensive therapy unit or of diagnosis of ARDS. IL-10 and TNF-alpha protein were detected in the plasma, BAL fluid, and alveolar macrophage supernatants by sandwich enzyme linked immunoabsorbent assays. RESULTS: The median IL-10 concentrations in the plasma and BAL fluid of patients with ARDS were significantly lower than the concentrations detectable in the plasma (median difference-17.5, 95% CI -52.4 to 1.31, p < 0.05) and BAL fluid of at risk patients (median difference -32.1, 95% CI -47.5 to 2.3, p < 0.05). There was a tendency towards enhanced concentrations of TNF- alpha detectable in the alveolar macrophage supernatants and the BAL fluid of patients with ARDS compared with at risk patients, although this did not reach statistical significance. No difference was observed in the plasma concentrations of TNF-alpha between the two groups. The ratios of TNF-alpha to IL-10 protein in the BAL fluid of patients with ARDS and at risk patients were 3.52 and 0.85, respectively (median difference 1.44, 95% CI 0.07 to 5.01, p < 0.01). There was no difference in alveolar macrophage production of IL-10 between the two groups. CONCLUSIONS: This study highlights the potential importance of the pro-inflammatory versus the anti-inflammatory imbalance in ARDS which may be reflected by the ratio of IL-10 and TNF-alpha in the lung.


     

Pathogenesis of beta(2)-microglobulin amyloidosis: role of monocytes/macrophages

beta(2)-microglobulin (beta(2)M) amyloidosis (A beta(2)M) is a serious, often incapacitating complication for patients undergoing long-term hemodialysis. Amyloid deposits composed of beta(2)M fibrils as the major constituent protein are mainly localized in joints and periarticular bone and lead to chronic arthralgias, carpal tunnel syndrome, and eventually destructive arthropathy. Although recent histologic studies have shown the accumulation of monocytes/macrophages around amyloid deposits, the factor(s) causing their infiltration and pathologic involvement have yet to be fully elucidated. Immunohistochemical staining reveals that macrophages in tenosynovial tissues express CD13, CD14, CD33, HLA-DR, and CD68 antigens on their surfaces and express interleukin (IL)-1 beta, tumor necrosis factor (TNF)-alpha, and IL-6. Many of these cells also express LFA-1 (CD11a/CD18), Mac-1 (CD11b/CD18), and VLA-4 (CD49d/CD29) on their surfaces. AGE-modified beta(2)M enhances chemotaxis of monocytes and stimulates macrophages to release bone-resorbing cytokines, such as IL-1 beta, TNF-alpha and IL-6. Via a RAGE-mediated pathway, AGE-modified, but not unmodified beta(2)M, significantly delays constitutive apoptosis of human peripheral blood monocytes. Monocytes survival in an advanced glycation end product (AGE) beta(2)M-containing microenvironment is associated with their phenotypic alteration into macrophage-like cells that generate more reactive oxygen species and elaborate greater quantities of IL-1 beta and TNF-alpha. Thus through regulation of their survival and differentiation, AGE beta(2)M in amyloid deposits may be able to influence the presence and quantity of infiltrated monocytes, and hence their biologic effects.     

Drotrecogin alfa (activated) does not affect intracellular production of interleukin-6 and tumor necrosis factor-alpha in endotoxin-stimulated human monocytes

In this ex vivo laboratory study, we investigated the effects of drotrecogin alfa (activated) (DA(a)), a recombinant form of human activated protein C, on the intracellular expression of interleukin (IL)-6 and tumor necrosis factor (TNF)-alpha on lipopolysaccharide (LPS)-stimulated human monocytes in a whole blood system. Whole blood samples from 10 healthy volunteers were stimulated with LPS (0.2 ng/mL) and incubated with 0.01, 0.1, 1, 10, and 100 nM of (final concentration) DA(a) for 3 h at 37 degrees C and 5% CO2. Intracellular expression of IL-6 and TNF-alpha was assessed by flow cytometry. Our investigation showed that DA(a), at any of the concentrations tested, did not affect intracellular IL-6 and TNF-alpha production in LPS-stimulated human monocytes after 3 h of incubation. The results of this investigation led us to conclude that any antiinflammatory activity of DA(a), if present, does not occur via detectible decreases in the production of proinflammatory cytokines IL-6 and TNF-alpha in human monocytes.     

Interleukin-17 stimulates the release of pro-inflammatory cytokines by blood monocytes in patients with IgA nephropathy

OBJECTIVE: Interleukin-17 (IL-17) is a newly discovered cytokine implicated in the regulation of inflammation. The present study was designed to explore whether IL-17 is involved in the immunoregulatory response in IgA nephropathy (IgAN). MATERIAL AND METHODS: We examined the in vitro effect of recombinant human IL-17 (rhIL-17) on pro-inflammatory cytokine release by peripheral blood monocytes (PBM) from patients with IgAN. Measurement of IL-1beta and tumor necrosis factor-alpha (TNF-alpha) was performed by means of a sandwich enzyme-linked immunosorbent assay. RESULTS: IL-1beta and TNF-alpha release were upregulated by rhIL-17 in a dose- and time-dependent fashion. Treatment of PBM from patients with IgAN with lipopolysaccharide and rhIL-17 resulted in significant activation and release of IL-1beta and TNF-alpha protein. Levels of IL-1beta and TNF-alpha were significantly higher in IgAN patients with the nephrotic syndrome (NS) than in patients without NS or in healthy subjects. We also provide information indicating that there is excessive production of IL-17 in IgAN patients. When IL-17-activated PBM were incubated in the presence of IL-10, IL-10 exerted a significant suppressive effect on IL-1beta and TNF-alpha release in vitro. CONCLUSION: IL-17 can stimulate the release of pro-inflammatory cytokines from PBM in patients with IgAN.     

右美托咪啶对脂多糖诱导大鼠外周血单核细胞Toll样受体4mRNA表达的影响

目的 探讨右美托咪啶对脂多糖(LPS)诱导大鼠外周血单核细胞Toll样受体4(TLR4)mRNA表达的影响.方法 健康雄性Wistar大鼠40只,取外周血分离培养单核细胞,采用随机数字表法,将其随机分为5组(n=8),A组:阴性对照;B组:单核细胞中加入LPS(终浓度为1μg/ml);C组:单核细胞中加入LPS(终浓度为1μg/ml)+右美托咪啶(终浓度为0.5 ng/ml);D组:单核细胞中加入LPS(终浓度为1μg/ml)+右美托咪啶(终浓度为5.0 ng/ml);E组:单核细胞中加入LPS(终浓度为1μg/ml)+右美托咪啶(终浓度为50.0 ng/ml).孵育24 h后,收集上清液,采用ELISA法测定TNF-α、IL-1β和IL-6的浓度,采用RT-PCR法测定TLR4 mRNA的表达.结果 与A组比较,B组TNF-α、IL-1p、IL-6的浓度升高,TLR4 mRNA表达上调(P＜0.01);与B组比较,C组、D组和E组TNF-α、IL-1β、IL-6的浓度降低,TLR4 mRNA表达下调(P＜0.05或0.01);与C组比较,D组和E组TNF-α、IL-1β、IL-6的浓度降低(P＜0.01),TLR4 mRNA表达差异无统计学意义(P＞0.05);D组和E组各指标比较差异无统计学意义(P＞0.05).结论 右美托咪啶可通过下调TLR4 mRNA表达,抑制TLR4的合成,从而抑制LPS诱导大鼠外周血单核细胞TNF-α、IL-1β和IL-6的生成与释放.

Abstract：

Objective To investigate the effects of different concentrations of dexmedetomidine on the expression of Toll-like receptor 4 (TLR4) mRNA in rat peripheral blood monocytes exposed to lipopolysaccharide ( LPS ). Methods Peripheral blood monocytes isolated from male Wistar rats were seeded in 24-well plate in RPMI 1640 liquid culture medium in CO2 incubator at 37 ℃ and 5% CO2 for 2 h, and were randomly divided into 5 groups ( n = 8 each): group A negative control; group B was exposed to LPS 1 μg/ml and C, D and E groups were exposed to LPS 1 μg/ml + dexmetomidine 0.5, 5.0 and 50.0 ng/ml respectively. The monocytes were then incubated for 24 h. The concentrations of TNF-α, IL-1β and IL-6 in the supernatant of the cultured monocytes were detected by ELISA. The expression of TLR4 mRNA in the monocytes was detected by RT-PCR.Results Exposure to LPS significantly increased the expression of TLR4 mRNA and the concentrations of TNF-α, IL-1β and IL -6 in group B as compared with group A ( P ＜ 0.01 ). Dexmedetomidine attenuated the LPS-induced increase in the expression of TLR 4 mRNA and the concentrations of TNF-α, IL-1β and IL-6 in a dose-dependent manner ( P ＜0.05or 0.01 ). Conclusion Dexmedetomidine can inhibit the synthesis of TLR4 and inhibit the secretion and dilivery of TNF-α, IL-1β and IL-6 by down-regulating the gene expression of TLR4 in rat peripheral blood monocytes exposed to LPS.     

Balance between cytokine production by peripheral blood mononuclear cells and reactive oxygen species production by monocytes in patients with chronic kidney disease

Hemodialysis (HD) and peritoneal dialysis are associated with inflammatory events and immunological incompetence. The purpose of this study was to evaluate the effect of both uremia and dialysis modality on the production of cytokines and reactive oxygen species (ROS) by monocytes. four groups of subjects were studied: 28 chronic kidney disease (CKD) patients, 14 chronic HD patients, 14 patients on continuous ambulatory peritoneal dialysis (CAPD) patients, and 14 healthy volunteers, peripheral blood mononuclear cells (PBMC) were isolated from blood samples and incubated for 24 hr with or without lipopolysaccharide (LPS). TNF-alpha and IL-10 production by PBMC and serum levels of these cytokines were quantified by ELISA. Aliquots of whole blood were incubated in vitro and ROS production and phagocytosis were quantified by flow cytometry. Compared to the control group, Staphylococcus aureus-stimulated ROS production by monocytes was significantly lower in the HD group. The highest levels of unstimulated TNF-alpha production in vitro were observed in the HD group. In the CKD group, as well as in the whole population, there were a negative correlation between TNF-alpha production by unstimulated PBMC and ROS production by S. aureus-stimulated monocytes and a positive correlation between PMA-stimulated ROS production by monocytes and unstimulated and LPS-stimulated IL-10 production by PBMC suggesting that the pro-inflammatory state in CKD patients is associated with decreased response to infectious challenges.     

Aberrant macrophage cytokine production is a conserved feature among autoimmune-prone mouse strains: elevated interleukin (IL)-12 and an imbalance in tumor necrosis factor-alpha and IL-10 define a unique cytokine profile in macrophages from young nonobese diabetic mice

Cytokines derived from macrophages (M?) play a critical role in the development of type 1 diabetes in the nonobese diabetic (NOD) mouse. Based on earlier findings from lupus-prone strains of inherent cytokine defects in M? , NOD M? were evaluated for intrinsically dysregulated cytokine production with the potential to initiate or exacerbate disease. Endotoxin-activated peritoneal M? from young prediseased NOD mice produced interleukin (IL)-1 and tumor necrosis factor (TNF)-alpha levels similar to those of M? from a panel of control strains but reduced compared with the congenic diabetes-resistant NOR strain. IL-6 and IL-10 production were similar in NOD and NOR M?, indicating that reduction in NOD IL-1 and TNF-alpha expression was selective. Nevertheless, the ratio of TNF-alpha and IL-10 production, a stringent index of normal M? function, distinguished NOD from all normal strains. The most striking feature of NOD M?, however, was their substantially elevated IL-12 production. This response was induced not only by endotoxin but also by bacillus Calmette-Guerin (BCG) and CD40 ligand and was associated with (and likely caused by) the enhanced and prolonged expression of p40 mRNA. Moreover, NOD M? IL-12 expression appeared to be near maximally induced by lipopolysaccharide (LPS) alone, because it was only slightly enhanced by the addition of gamma-interferon, a stimulus that substantially elevated LPS-induced IL-12 production in M? from normal strains. Accompanied by a unique profile of TNF-alpha and IL-10, the dramatic elevation of IL-12 expression by NOD M? reflects intrinsic defects of the innate immune system with the potential to initiate and propagate the pathogenic autoreactive T-helper type 1 response characteristic of type 1 diabetes.     

Reduced capacity of whole blood leucocytes to express tumour necrosis factor-alpha and interleukin-10 following major orthopaedic surgery

BACKGROUND: Severe trauma is a challenge to the immune response and may cause reduced immune capacity. As a marker of decreased cellular activity, studies with ex vivo lipopolysaccharide (LPS) stimulation of whole blood or isolated mononuclear cells from injured patients have revealed reduced production of inflammatory cytokines. To gain further insight into immune alterations in orthopaedic surgery, we studied LPS-induced tumour necrosis factor (TNF)-alpha and interleukin (IL)-10 in whole blood of patients during peri- and postoperative phases of total hip replacement. METHODS: Four females and 3 males undergoing elective total hip replacement were included in the study. Ex vivo LPS-induced TNF-alpha and IL-10 were measured in a whole blood assay before, during and at 1 and 6 days after operation. In addition, the counts of white blood cells were determined. RESULTS: During the operation, there were significant reductions in the number of monocytes, but at day 1 and 6 after surgery, there were significant increases as compared to the levels before surgery. The capacity of whole blood to express TNF-alpha and IL-10 did not change significantly during the operation and the following postoperative day. At day 6, however, there were significant reductions in expression of both TNF-alpha and IL-10 as compared to the levels before the operation. In relation to the values of monocytes, there was a significant reduction in the expression of TNF-alpha also at day 1 after operation. CONCLUSION: Our data indicate that in the course of at least 6 days after a major orthopaedic trauma, there is suppression of the whole blood capacity to express the inflammatory cytokine TNF-alpha and the anti-inflammatory cytokine IL-10 when exposed to LPS. During this time, then, the patient is particular susceptible to septic complications.