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R H Beelen

Publications and source records attributed to R H Beelen.

At least 19 recordsLinked to original sources

Analysis of monocyte chemotactic protein-1 production in different major histocompatability complex-restricted antigen presentation systems.

In the present study the production of the CC chemokine monocyte chemotactic protein-1 (MCP-1) in several MHC II-restricted antigen presentation systems was investigated in vitro. To assess which type of antigen-presenting cell (APC) influences MCP-1 production during antigen presentation, cultures enriched for different APC populations were prepared and MCP-1 production was determined. Our results showed that APCs that effectively induce a T cell response also produce elevated amounts of MCP-1. The MCP-1 production is highest in the memory-driven secondary response against a single antigen. Despite a massive T cell proliferation, low MCP-1 concentrations are found in Con A-induced cultures. These results suggest that T cell proliferation alone is not sufficient for MCP-1 production and that stimulation of the APC during the process of antigen presentation results in MCP-1 production. Based on our results and the literature, we propose a model for MCP-1 as an enhancer of the adaptive immune response.

Antigen Presentation↗

Monocyte-chemoattractant-protein-1-mediated migration of human monocytes towards blasts from patients with acute myeloid leukemia.

PURPOSE: In the present study the possible clinical relevance of monocyte chemoattractant protein (MCP)-1 in patients with acute myeloid leukemia (AML) was established. METHODS: The pattern of migration of human monocytes towards the supernatants of blasts from 15 patients with AML was studied and the role of MCP-1, produced by these blasts, was assessed. RESULTS: In 4 patients (group 1) the amount of monocyte migration was low and not inhibited by the addition of anti-hMCP-1. In 11 patients, the amount of monocyte migration was high; after addition of anti-hMCP-1, monocyte migration was either completely (8 patients, group 2), or partly or not (3 patients, group 3) inhibited to the level of chemokinesis. In groups 1 and 2, there was a good correlation (r = 0.67) between the concentration of MCP-1 in the supernatants and the amount of monocyte migration. In group 3, such a correlation was not evident, suggesting that another chemokine might be involved or MCP-1 function was impaired by an unknown substance. Finally, measurements of MCP-1 during culture of AML blasts showed that the time at which maximal amounts of MCP-1 are produced differs between the AML samples. CONCLUSIONS: AML blasts produce different amounts of MCP-1, which plays an important role in monocyte migration towards most AML blasts. Therefore, in the context of adoptive immunotherapy, MCP-1 might be involved in future tumor vaccination programmes using autologous MCP-1-transfected irradiated AML blasts.

Cancer Vaccines↗

Immune-stimulating effects of low-dose perioperative recombinant granulocyte-macrophage colony-stimulating factor in patients operated on for primary colorectal carcinoma.

BACKGROUND: Surgery induces a postoperative immunosuppression, thereby possibly facilitating the outgrowth of pre-existing occult metastases or the seeding of disseminated tumour cells in patients with primary colorectal carcinoma operated on with curative intent. The hypothesis that adjuvant therapy with perioperative recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) would minimize postoperative immunosuppression was investigated in this pilot study. METHODS: Patients were allocated randomly to receive daily subcutaneous injections with either saline (n = 8) or rhGM-CSF 2.8 microg per kg body-weight (n = 8) from 3 days before operation until 4 days afterwards. Phytohaemagglutinin (PHA) skin test reactivity, monocyte human leucocyte antigen (HLA) DR expression and the extent of the acute-phase response, by determination of white blood cell count and differentiation, plasma interleukin (IL) 6 levels and body temperature in the perioperative period, were examined. RESULTS: rhGM-CSF treatment minimized postoperative suppression in PHA skin test reactivity and increased the numbers of neutrophils and monocytes while enhancing the expression of HLA-DR in the postoperative period. Additionally, both postoperative plasma IL-6 levels and the incidence of fever tended to be higher in the rhGM-CSF group. CONCLUSION: In this pilot study, perioperative administration of low-dose rhGM-CSF stimulated certain immune functions that are normally depressed after operation. The implications for the antitumour responses directly after operation and the formation of liver metastases are currently under investigation.

Adjuvants, Immunologic↗

Rat models in peritoneal dialysis.

BACKGROUND: It is widely accepted that the currently used dialysis solutions are not biocompatible with the peritoneal membrane. Therefore, animal studies have been performed to study different aspects of peritoneal dialysis. However, representative models mimicking the human situation are not yet available. METHODS: The effect of a single injection of peritoneal dialysis (PD) fluid on the cellular composition was studied. Thereafter, the effect of a single injection of PD fluid on bacterial clearing was tested over time. Finally, an in vivo rat model was established to study the effects of long-term exposure to PD fluid on the peritoneal membrane and the local host defence (peritoneal cells). RESULTS: In the rat model, long-term daily exposure is possible. The 'drop-out' after 9-10 weeks on the most commonly used PD fluid Dianeal 3.86%, however, is approximately 50% due to omental wrapping. In the remaining study group, large differences were observed (as compared with controls), especially with respect to morphological parameters. CONCLUSIONS: The rat peritoneal continuous exposure model seems to have potential for intervention studies, since it uses no additions, no antibiotics and no omentomectomy, and gives continuous long-term exposure to PD fluid. However, problems still remain: 'drop-out' is quite often seen and this non-uraemic exposure model does not totally mimic the situation present in continuous ambulatory PD patients.

Animals↗

Effect of PD fluid instillation on the peritonitis-induced influx and bacterial clearing capacity of peritoneal cells.

BACKGROUND: The commonly used peritoneal dialysis fluids contain glucose as the osmotic agent. Heat sterilization leads to the formation of glucose degradation products which contribute, together with glucose, to the formation of advanced glycation end-products (AGEs). AGEs have been shown to be present in the peritoneal cavity. Methods have been developed to minimize the amount of glucose degradation products in peritoneal dialysis fluids. In a rat peritoneal dialysis model, we compare the effect of a commonly used peritoneal dialysis fluid, Gambrosol, with a newly developed peritoneal dialysis fluid, PD-Bio, on the influx and functional capacity of the peritoneal cells after 2 weeks of peritoneal dialysis fluid instillation. METHODS: Three groups of animals were used: rats received daily infusion with 15 ml of either 4% Gambrosol (group 1) or 4% PD-Bio (group 2), and a control group of animals did not receive fluid (group 3). After 2 weeks of PD fluid instillation, all the animals were injected with a 0.5 ml suspension containing 3x10(8) colony-forming units of Staphylococcus aureus. The in vivo bacterial clearing capacity was determined after 15 h. RESULTS: A statistically significant higher leukocyte influx was found in the control group compared with both PD fluid-injected groups. No statistical differences in bacterial clearing were observed among the three groups, although the number of bacteria recovered from the PD-Bio group tended to be lower than that from the Gambrosol group. Moreover, in both PD fluid instillation groups, the bacteria tended to be cleared more slowly compared with the control group. The number of mesothelial cells in the PD fluid groups was significantly greater than in the control group. CONCLUSION: No differences were observed in bacterial clearing capacity, leukocyte influx and mesothelial cell number after a 2 week exposure of the peritoneal cavity to Gambrosol vs PD-Bio.

Animals↗

Accumulation of omental mast cells during peritoneal dialysis.

OBJECTIVE: New vessel formation has been reported in various tissues during peritoneal dialysis (PD). In that line, mast cells can produce factors such as tryptase, chymase, or basic fibroblast growth factor that might contribute to the formation of new vessels. In the present study, the association of mast cells with neovascularization during PD was investigated. METHODS: Rats received daily 10 mL infusions of conventional 3.86% glucose-containing PD fluid over a 10-week period. The infusions were delivered through a subcutaneously implanted mini access port that was connected by catheter to the peritoneal cavity. Untreated rats served as a control group. The number of blood vessels and of mast cells in the omentum were counted. Also, the number of peritoneal mast cells was determined. RESULTS: Chronic exposure to PD fluid resulted in an increased number of mast cells in the omentum. However, no clear correlation was found between the elevated number of omental blood vessels and the number of mast cells in the omentum or in the peritoneal cavity. CONCLUSIONS: Omental mast cells accumulated dramatically upon exposure to PD fluid. The actual role of accumulated omental mast cells in the induction of angiogenesis during PD should, however, be further investigated.

Animals↗

Laparoscopic surgery preserves monocyte-mediated tumor cell killing in contrast to the conventional approach.

BACKGROUND: Experimental animal research shows that immunologic defenses against tumor cells are disturbed by surgical trauma, resulting in an increased rate of tumor implantation and the growth of subsequent metastases. Minimally invasive surgery is associated with a preservation of postoperative immunologic functions and, in animal models, with decreased tumor growth. The objective was to study the influence of several surgical procedures, approached conventionally and laparoscopically, on interleukin-6 (IL-6) and monocyte-mediated cytotoxicity (MMC). METHODS: Five groups of five patients each were included in this prospective study: laparoscopic cholecystectomy (minor trauma) group, Nissen fundoplication (laparoscopic and conventional as moderate trauma) groups, and sigmoid colectomy (laparoscopic and conventional as major trauma) groups. Preoperatively, 1 and 4 days after surgery, IL-6 and MMC against SW948 colon cancer cell line were determined. RESULTS: The IL-6 levels differed significantly between the three laparoscopic procedures (p = 0.004) and increased according to the degree of trauma. There was no significant difference in MMC between the three laparoscopic procedures. However, MMC was suppressed after conventional procedures and preserved after laparoscopic procedures (p = 0.001). There was no correlation between IL-6 levels and changes in MMC. CONCLUSIONS: More extensive laparoscopic procedures induce increased levels of IL-6, reflecting higher levels of trauma. Conventional surgical procedures result in depressed MMC in the postoperative period. After laparoscopic procedures, MMC is preserved. These findings may be of importance in preventing implantation and growth of cancer cells spread by surgical manipulation.

Adult↗

The influence of laparoscopic surgery on postoperative polymorphonuclear leukocyte function.

BACKGROUND: Laparoscopic surgery is thought to result in a better preservation of patients' immunological defenses. Polymorphonuclear leukocytes (PMN) are the most important effector cells in the elimination of pathogenic microorganisms. Because little is known about their function after laparoscopic surgery, we studied PMN phagocytosis, antigen expression, and oxygen radical production. METHODS: In this study, 17 patients scheduled for Nissen fundoplication were randomly assigned to undergo either a laparoscopic or conventional procedure. To study phagocytic capacity, PMN were incubated with fluorescein isothiocyanate (FITC)-labeled Staphylococcus aureus. Plasma opsonic capacity was measured by comparing PMN phagocytosis in the presence of patients' own plasma with phagocytosis in the presence of control plasma. Cellular activation was measured by the expression of various cell surface markers and by assessment of PMA-stimulated oxidative burst. RESULTS: Phagocytosis by PMN in the presence of patients' plasma was significantly lower 2 h after the conventional operation. No decrease in phagocytosis was observed when control plasma was used, indicating a decreased opsonic capacity of plasma after conventional surgery. No changes were observed after laparoscopic surgery. Furthermore, CD11b expression was significantly lower after the laparoscopic approach, indicating a blunted cellular activation. A significantly lower PMA-stimulated oxidative burst further confirmed the tempered stimulation after laparoscopic surgery. CONCLUSIONS: Laparoscopic surgery results in a preservation of the plasma opsonic capacity, and thereby the ability of PMN to phagocytose bacteria. Moreover, the postoperative cellular activation is reduced. The preserved phagocytosis and the blunted activation may prevent the development of postoperative infectious complications.

Adult↗

Bactericidal/permeability-increasing protein preserves leukocyte functions after major liver resection.

OBJECTIVE: To analyze postoperative leukocyte functions in patients undergoing hemihepatectomy, and to assess the effect of treatment with the endotoxin-neutralizing agent bactericidal/permeability-increasing protein (rBPI21). SUMMARY BACKGROUND DATA: Extensive liver resection is associated with a high incidence of infectious complications. Because elimination of pathogenic microorganisms occurs mainly by leukocytes, this increased rate of infections is most likely due to an impaired function of these cells. Endotoxin, translocated from the gut into the systemic circulation as a result of increased gut permeability and reduced hepatic clearance function after major liver resection, may play an important role in the impairment of posthepatectomy leukocyte function. METHODS: To investigate whether hemihepatectomy results in impaired leukocyte functions and to determine the role of endotoxin in this process, leukocyte oxidative burst and leukocyte antigen expression were studied in three groups of patients: patients undergoing a hemihepatectomy and receiving rBPI21 treatment, patients undergoing hemihepatectomy and receiving placebo, and as an extra control group patients undergoing other major abdominal surgeries. Blood samples were collected before surgery, 2 hours after surgery, and at days 1, 2, 5, and 7. Phorbol myristate acetate-stimulated oxidative burst was measured using dihydrorhodamine, and leukocyte surface expression of the antigens CD11b, CD16, and CD14 was investigated by indirect immunofluorescence. Both oxidative burst and membrane surface expression were quantified by flow cytometry. An indication of the antiendotoxin effect of rBPI21 treatment was provided by assessment of plasma lipopolysaccharide binding protein (LBP) levels by enzyme-linked immunosorbent assay. RESULTS: The oxidative burst in the hemihepatectomized patients receiving placebo and the controls increased 2 hours after surgery, whereas it decreased in the rBPI21-treated patients, resulting in significant differences between the groups. On day 1, neutrophil CD11b expression and monocyte CD14 expression in the rBPI21-treated patients and controls were significantly lower than in the placebo group. At 2 hours, CD16 expression in the placebo-treated patients was significantly higher than in the rBPI21-treated patients and controls. On day 5 and day 7, plasma LBP levels were significantly higher in the placebo-treated patients compared with the rBPI21-treated patients. CONCLUSIONS: The results of this study show that patients undergoing major liver resection have an increased activation of leukocytes compared with those undergoing other major abdominal surgery. This enhanced activation may contribute to the increased risk of infection in these patients. Administration of the endotoxin-neutralizing agent rBPI21 to hemihepatectomy patients was shown to reduce plasma LBP levels, to preserve leukocyte functions partially, and to reduce leukocyte activation to the level of other, nonhepatic abdominal surgery.

Acute-Phase Proteins↗

The degree of branching of the glycans of alpha(1)-acid glycoprotein in asthma. A correlation with lung function and inflammatory parameters.

Alpha(1)-acid glycoprotein (AGP) is a plasma protein belonging to the group of acute-phase proteins. It contains five N-linked glycans which, depending on pathophysiologic state, differ in their degree of branching (i.e., in the relative proportions of di-, tri-, and tetraantennary glycans). Changes in the degree of branching of these glycans have been shown to affect various immunomodulatory properties of AGP. We wanted to investigate whether changes occur in the branching of AGP glycans in plasma and in bronchoalveolar lavage fluid (BALF) in asthma. For this purpose, we selected three groups of patients for study: patients with atopic asthma (AA), atopic nonasthmatic patients, and a group of patients with various interstitial lung diseases (ILDs). The plasma AGP concentration was normal in both atopic study groups, but was increased in ILD patients. In contrast, the branching of glycans of AGP was altered in subjects with AA, whereas it was normal in the other study groups. The presence of asthma symptoms correlated with the increased glycan branching of AGP in both plasma and BALF. Additionally, the degree of branching of AGP in BALF was related to FEV(1), to the provocative dose of histamine causing a 20% decrease in FEV (PD(20)), and to the number of eosinophils. In conclusion, asthma is accompanied by changes in the branching of AGP glycans that indicate an inflammatory reaction that differs markedly from a normal acute-phase response, in which decreased branching of AGP occurs.

Adolescent↗

Regulation of CD 163 on human macrophages: cross-linking of CD163 induces signaling and activation.

CD163 is a member of the group B scavenger receptor cysteine-rich (SRCR) superfamily. This study describes aspects of the tissue distribution, the regulation of expression, and signal transduction after cross-linking of this receptor at the cell surface of macrophages. CD163 showed an exclusive expression on resident macrophages (e.g., red pulp macrophages, alveolar macrophages). The expression was inducible on monocyte-derived macrophages by glucocorticoids but not by interleukin-4 (IL-4), granulocyte-macrophage colony-stimulating factor (GM-CSF), and interferon-gamma. The combination of IL-4 or GM-CSF with glucocorticoids resulted in a further increase. Subcellular analysis of alveolar macrophages by immunoelectron microscopy showed a plasma membrane localization of the antigen. Cross-linking of CD163 with monoclonal antibody induced a protein tyrosine kinase-dependent signal that resulted in (1) slow-type calcium mobilization, (2) inositol triphosphate production, and (3) secretion of IL-6 and GM-CSF. The data suggest a function for the SRCR-superfamily receptor CD163 in the regulation of inflammatory processes by macrophages.

Animals↗

Impaired leukocyte phagocytosis in patients undergoing hemihepatectomy for liver metastases.

Patients undergoing partial hepatectomy have an increased susceptibility to infection. To investigate whether this increased risk is related to impaired leukocyte function, we studied polymorphonuclear leukocyte (PMN) phagocytosis in patients undergoing a hemihepatectomy because of liver metastasis (LM, n = 11) and in patients undergoing major abdominal surgery because of abdominal malignancy (AM, n = 8). Eight healthy volunteers (HVs) served as controls. Leukocyte suspensions were incubated with fluorescein isothiocyanate-labeled Staphylococcus aureus, and phagocytosis was measured by flow cytometry. Preoperative PMN phagocytosis, in the presence of autologous plasma, was significantly less in patients with LM compared with patients with AM or HVs. This impaired phagocytosis was potentially restored in the presence of normal plasma. The decreased phagocytic capacity of PMNs from patients with LM was not related to levels of known plasma opsonins or phenotypic changes of PMNs. Rather, it was related to a deficiency of unidentified plasma factors. After surgery, the phagocytic capacity of PMNs of patients with AM decreased by approximately 30%, which correlated with decreasing levels of immunoglobulin G and C3. In conclusion, patients with LM had a decreased PMN phagocytic capacity before surgery. This impairment in phagocytosis disappeared 1 week after surgery. We propose that the presence of LM leads to a deficiency of factor(s) in the blood that impairs PMN phagocytic capacity.

Case-Control Studies↗

Immunological consequences of laparoscopic surgery, speculations on the cause and clinical implications.

BACKGROUND: Immune suppression is an established consequence of surgical stress and trauma. Postoperative changes in the systemic immune system are proportional to the degree of surgical trauma and subsequent immune suppression may be implicated in the development of infectious complications and tumor metastasis formation. Laparoscopic surgery reduces the magnitude of the operative trauma and is thought to preserve postoperative immunological defenses. METHODS: Relevant literature concerning postoperative immune functions and laparoscopic surgery was reviewed and clinical implications are discussed. RESULTS: The influence of laparoscopic surgery on the postoperative systemic immune response is significantly less after laparoscopic cholecystectomy than with the conventional approach. Few immunological data are available concerning more advanced laparoscopic procedures. Various animal model studies of postoperative septic complications and tumor growth show that the postoperative preservation of the systemic immune response after laparoscopic surgery can have enormous clinical advantages. CONCLUSION: Laparoscopic surgery preserves the postoperative immunological defenses. In the future, this may imply a lower number of infections, less local recurrence and even fewer distant metastases. Prospective randomized studies are necessary to see whether these suspected advantages can be demonstrated in clinical practice.

Cholecystectomy, Laparoscopic↗

Expression of MCP-1 by reactive astrocytes in demyelinating multiple sclerosis lesions.

The pathology of multiple sclerosis (MS) is characterized by breakdown of the blood-brain barrier (BBB), accompanied by infiltration of macrophages and T lymphocytes into the central nervous system (CNS). The migration of these cells into the CNS parenchyma may be partly regulated by chemokines. The aim of this study was therefore to investigate the cellular localization of the potent monocyte- and T-cell-attracting chemokine monocyte chemoattractant protein (MCP)-1 by immunohistochemistry on postmortem brain tissue from MS and normal control cases. Brain tissue samples of six MS patients and four patients without a history of brain disease were neuropathologically classified according to characteristic (immuno)histochemical staining patterns. Frozen tissue sections of active demyelinating MS lesions, chronic active demyelinating MS lesions, and normal control brain were immunohistochemically stained with a monoclonal antibody directed against MCP-1. In active demyelinating MS lesions as well as in chronic active MS lesions, reactive hypertrophic astrocytes were strongly immunoreactive for MCP-1, whereas perivascular and parenchymal foamy macrophages did not express MCP-1 protein. These results suggest a significant role for the beta-chemokine MCP-1, synthesized in vivo by reactive hypertrophic astrocytes, in the recruitment and activation of myelin-degrading macrophages and thereby contributing to the evolution of MS lesions.

Adult↗

Glucocorticoids modulate the development of dendritic cells from blood precursors.

Dendritic cells (DC) are professional antigen-presenting cells, capable of priming naive T cell responses. Glucocorticoids (GC) are frequently used in asthmatic patients. In this study we describe the effects of GC on the development and function of monocyte-derived DC (MoDC) in vitro and in vivo. Monocytes from healthy individuals were isolated and incubated with granulocyte-macrophage colony-stimulating factor (GM-CSF) and IL-4 for 6 days, to induce maturation into MoDC. To study the role of GC on DC differentiation in vitro cells were incubated with dexamethasone at different stages of MoDC development. At day 6 cells were characterized phenotypically by flow cytometry and functionally in an allogeneic mixed leucocyte reaction. To study the effect of GC in vivo patients with mild/moderate atopic asthma were selected. In one group no GC were used, whereas the other group used inhalation GC. MoDC from these patients were generated as described above and tested functionally. Incubation of MoDC or its peripheral blood precursors with dexamethasone decreased the accessory potency dose-dependently. The functional differences could not be explained by the changes in the expression of MHC II and the costimulatory molecules CD40 and CD86. The relevance of this mechanism was confirmed for the in vivo situation as well. MoDC from patients using inhalation GC showed a decreased accessory potency. These data suggest a modulatory effect of GC therapy at the level of the peripheral blood monocyte. The results indicate that GC influence DC development and function in vitro as well as in vivo.

Administration, Inhalation↗

Infection of human endothelial cells with Staphylococcus aureus induces the production of monocyte chemotactic protein-1 (MCP-1) and monocyte chemotaxis.

Bacterial infection coincides with migration of leucocytes from the circulation into the bacterium-infected tissue. Recently, we have shown that endothelial cells, upon binding and ingestion of Staphylococcus aureus, exhibit proinflammatory properties including procoagulant activity and increased intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) expression on the cell surface, resulting in hyperadhesiveness, mainly for monocytes. The enhanced extravasation of monocytes to bacterium-infected sites is facilitated by the local production of chemotactic factors. From another study we concluded that the locally produced chemokine MCP-1 is important in the recruitment of monocytes to the peritoneal cavity in a model of bacterial peritonitis. In the present study we investigated whether cultured human endothelial cells after infection with bacteria produce and release MCP-1, which in turn stimulates monocyte chemotaxis. We observed that endothelial cells released significant amounts of MCP-1 within 48 h after ingestion of S. aureus. This was dependent on the number and the virulence of the bacteria used to infect the endothelial cells. The kinetics as well as the amount of MCP-1 released by S. aureus-infected endothelial cells differed markedly from that released by endothelial cells upon stimulation with IL-1beta. Supernatant from S. aureus-infected or IL-1beta-stimulated cells promoted monocyte chemotaxis which was almost entirely abrogated in the presence of neutralizing anti-MCP-1 antibody, indicating that most of the chemotactic activity was due to the release of MCP-1 into the supernatant. Our findings support the notion that endothelial cells can actively initiate and sustain an inflammatory response after an encounter with pathogenic microorganisms, without the intervention of macrophage-derived proinflammatory cytokines.

Cells, Cultured↗

A prospective randomized study of the systemic immune response after laparoscopic and conventional Nissen fundoplication.

BACKGROUND: Laparoscopic techniques are thought to reduce the postoperative immunologic and metabolic changes of conventional operations. Until now, the only clinical data available were obtained from patients operated on for symptomatic gallstones; moreover, few studies were randomized. This randomized prospective study compares the systemic immune response after laparoscopic and conventional Nissen fundoplication. METHODS: Seventeen patients scheduled for Nissen fundoplication were randomly assigned to undergo either a laparoscopic or a conventional procedure. Postoperative inflammatory response was assessed by measuring the white blood cell count, C-reactive protein, and soluble tumor necrosis factor receptors p55 and p75. Postoperative immune function was assessed by measuring monocyte HLA-DR expression and the stress response was assessed by measuring plasma cortisol concentrations. RESULTS: Laparoscopic surgery resulted in significantly lower plasma CRP levels 1 day after surgery. Both approaches resulted in a significant decrease in HLA-DR expression within 2 hours after surgery. After the laparoscopic approach, postoperative expression was restored to preoperative values within 1 day after surgery. However, after conventional surgery HLA-DR expression remained suppressed and did not return to preoperative values until the fourth postoperative day. No significant differences between the 2 procedures were observed in white cell blood count, sTNFr-p55 and p75, nor in postoperative cortisol levels. CONCLUSIONS: Although both laparoscopic and conventional Nissen fundoplication result in an activation of the systemic immune response, this study suggests that this response could be less after the laparoscopic approach. The differences found may reflect a lower risk for postoperative infective complications.

Adult↗