Natural killer cells are pivotal for in vivo protection following systemic infection by Sporothrix schenckii.

Natural killer (NK) cells are one of the first cell types to enter inflammation sites and have been historically known as key effector cells against tumours and viruses; now, accumulating evidence shows that NK cells are also capable of direct in vitro activity and play a protective role against clinically important fungi in vivo. However, our understanding of NK cell development, maturation and activation in the setting of fungal infections is preliminary at best. Sporotrichosis is an emerging worldwide-distributed subcutaneous mycosis endemic in many countries, affecting humans and other animals and caused by various related thermodimorphic Sporothrix species, whose prototypical member is Sporothrix schenckii. We show that following systemic infection of BALB/c mice with S. schenckii sensu stricto, NK cells displayed a more mature phenotype as early as 5 days post-infection as judged by CD11b/CD27 expression. At 10 days post-infection, NK cells had increased expression of CD62 ligand (CD62L) and killer cell lectin-like receptor subfamily G member 1 (KLRG1), but not of CD25 or CD69. Depletion of NK cells with anti-asialo GM1 drastically impaired fungal clearance, leading to a more than eightfold increase in splenic fungal load accompanied by heightened systemic inflammation, as shown by augmented production of the pro-inflammatory cytokines tumour necrosis factor-α, interferon-γ and interleukin-6, but not interleukin-17A, in the spleen and serum. Our study is, to the best of our knowledge, the first to demonstrate that a fungal infection can drive NK cell maturation in vivo and that such cells are pivotal for in vivo protection against S. schenckii.

Flow cytometry as a diagnostic tool for identifying total hip arthroplasty loosening and differentiating between septic and aseptic cases.

PURPOSE: Implant loosening represents one of the major factors of total hip arthroplasty (THA) failure. The purpose of this study was to identify specific markers indicative of septic and aseptic loosening in patients that underwent THA. METHODS: Flow cytometry was performed in blood samples of 20 patients with loosening (10 septic/10 aseptic). Additional ten healthy individuals served as a control group. The expression of surface receptors and cytoplasmic molecules in patients that underwent THA was quantified. CD62L, CD18, CD11a, CD11b and CD11c expressions were evaluated and correlated with the presence of loosening. Also, a comparison between septic and aseptic THA loosening characteristics was performed. RESULTS: The mean fluorescence intensity (MFI) for CD18 was significantly decreased on all leukocytes subsets in both septic and aseptic loosening compared to control group (p < 0.005 in all occasions). Patients with aseptic loosening showed increased MFI for CD11b in granulocytes and for CD11c in monocytes and granulocytes compared to the control and aseptic group (p = 0.02 and p = 0.005, respectively). In patients with septic loosening, an increase in MFI for CD11c was observed in monocytes only compared to control group (p = 0.03). The comparison between aseptic and septic loosening showed significantly lower CD18 MFI value in granulocytes for aseptic loosening (p = 0.008). CONCLUSIONS: CD11 and CD18 MFI values appear to be indicative of loosening in THAs. Flow cytometry markers can be used to identify THA loosening, as well as to differentiate between septic and aseptic cases.

Immune perturbations in patients along the perioperative period: alterations in cell surface markers and leukocyte subtypes before and after surgery.

BACKGROUND: Surgery renders patients susceptible to life-threatening complications, including infections, multiple organ failure, and presumably cancer metastases. Surgery-induced immune perturbations were suggested to contribute to such deleterious effects, but also to facilitate post-injury healing. Preoperative psychological and physiological stress responses may contribute to these immune perturbations, and could thus jeopardize patients even before surgery. The current study assessed the effects of various operations on an array of immune indices during the perioperative period. To qualify immune changes before surgery, patients' immune status was also compared to that of healthy controls. METHODS: A total of 81 subjects (operated patients and healthy controls) provided up to five daily blood samples during the perioperative period, for assessment of leukocyte subtypes (granulocytes, monocytes, Tc, Th, NK, NKT, CD4+CD25+, CD8(bright)CD4(dim), and B cells) and their surface markers (HLA-DR and LFA-1). RESULTS: Even before surgery patients displayed immune perturbations, including reduced lymphocyte HLA-DR expression and increased monocyte LFA-1 expression. Following surgery, we recorded a reduction in lymphocyte numbers that was subtype specific, increased granulocyte numbers, and reduced expression of HLA-DR by lymphocytes and monocytes. Finally, no significant associations were found between alteration in leukocyte numbers and cell surface markers (although these indices showed high correlations with other variables), implying differential mediating mechanisms. CONCLUSION: Several immune alterations are manifested prior to surgery, and contribute to the marked postoperative changes, which are commonly interpreted as immune suppression. We discuss the possible adaptive and maladaptive nature of these perturbations in the context of natural injury, stress, and surgery.

Blockade of C5a and C5b-9 generation inhibits leukocyte and platelet activation during extracorporeal circulation.

Complement activation contributes to the systemic inflammatory response induced by cardiopulmonary bypass. At the cellular level, cardiopulmonary bypass activates leukocytes and platelets; however the contribution of early (3a) versus late (C5a, soluble C5b-9) complement components to this activation is unclear. We used a model of simulated extracorporeal circulation that activates complement (C3a, C5a, and C5b-9 formation), platelets (increased percentages of P-selectin-positive platelets and leukocyte-platelet conjugates), and neutrophils (upregulated CD11b expression). to specifically target complement activation in this model, we added a blocking mAb directed at the human C5 complement component and assessed its effect on complement and cellular activation. Compared with a control mAB, the anti-human C5 mAb profoundly inhibited C5a and soluble C5b-9 generation and serum complement hemolytic activity but had no effect on C3a generation. Additionally, the anti-human C5 mAb significantly inhibited neutrophil CD11b upregulation and abolished the increase in P-selectin-positive platelets and leukocyte-platelet conjugate formation compared to experiments performed with the control mAb. This suggests that the terminal components C5a and C5b-9, but not C3a, directly contribute to platelet and neutrophil activation during extracorporeal circulation. Furthermore, these data identify the C5 component as a site for therapeutic intervention in cardiopulmonary bypass.

Pain-related activation of leukocyte cellular adhesion molecules: preliminary findings.

BACKGROUND/AIMS: Acute adrenergic stressors have been found to activate neuroendocrine pathways that can alter leukocyte migration and activity. Leukocyte migration is known to affect the pathophysiology of inflammatory disease processes. This study examined the effects of acute experimental pain on catecholamine and cortisol levels and leukocyte expression of cellular adhesion molecules. METHODS: Healthy subjects (n = 10) underwent 45 min of acute experimental pain using earlobe electrical stimulation. Measures included sensory and affective pain responses, perceived stress, circulating levels of catecholamines, cortisol, and expression of integrin (CD11a+) cellular adhesion molecules on leukocyte subsets. Data were collected at baseline, after 22.5 and 45 min of pain, and 180 min after pain cessation. RESULTS: Experimental pain acutely increased circulating levels of epinephrine, along with increases in the number of CD8+CD11a+ leukocytes and the density of CD11a molecules on CD8+ cells. Positive correlations were found between pain and stress scores, and the number of CD8+CD11a+ leukocytes. CONCLUSION: Acute pain induces elevated cellular adhesion molecule expression on leukocytes, which has possible implications for increasing leukocyte infiltration and disease exacerbation in patient populations with inflammatory syndromes.

Atherosclerosis and inflammation. Patterns of cytokine regulation in patients with peripheral arterial disease.

Inflammatory phenomena at sites of atherosclerotic plaques are increasingly thought to be major determinants of the progression and clinical outcome of atherosclerotic disease. Therefore, attention is being paid to systemic markers/mediators which may reflect the inflammatory activity in the plaques. This study evaluates the pattern of the main proinflammatory cytokines tumor necrosis factor-alpha (TNFalpha), interleukin-1beta (IL-1beta), and interleukin-6 (IL-6), their soluble receptors/antagonist, and a variety of inflammatory markers, in patients with peripheral arterial disease (PAD). Eight patients with PAD suffering from claudicatio intermittens (CI), eight with critical limb ischemia (CLI) and eight controls (C) were studied. Blood samples were collected at baseline in all groups and. for C and CI, immediately after and 4 h after a 30-min treadmill test. Baseline: no differences in cytokine plasma levels were detected among the three groups. In contrast, soluble receptors of TNF (type I and II) and of IL-6, and IL-1beta receptor antagonist (IL-1ra) were increased in CI and CLI patients, as compared to C. Of note, IL-Ira correlated with the occurrence and stage of the disease in a highly significant proportion of the patients, reaching a predictive value for the disease of P < 0.0001. The opposite trend was observed for the soluble receptor of IL-1beta. Notably, in the patients no alterations could be found in white blood cell counts, expression of CD11c adherence molecule by circulating monocytes or, in vitro. O2- release from zymosan-activated neutrophils. Moreover, plasma levels of platelet activating factor (PAF), of neutrophil elastase and of the acute phase reactants C-reactive protein (CRP) and alpha1-acid glycoprotein were not found to be significantly altered. In contrast, the acute-phase proteins alpha1-antitrypsin (alpha1AT) and haptoglobin (HG) were found to be increased. Effect of treadmill: IL-1beta and TNFalpha remained at baseline levels following exercise, and IL-6 dropped to undetectable levels. Among cytokine antagonists, again the most relevant changes concerned the IL-1ra, which was significantly increased immediately after the treadmill test, both in CI and C, and returned to baseline levels after 4 h. In contrast, soluble TNFalpha, IL-1beta and IL-6 receptors, PAF, and the other markers of leukocyte activation were not found to be altered. Soluble TNFalpha and IL-6 receptors were shown to inhibit the biological effects of their ligands. Similarly, IL-1ra and the acute phase proteins alpha1AT and HG have been reported to exert anti-inflammatory functions. The increased plasma levels of these agents, together with low levels of inflammatory cytokines and other pro-inflammatory mediators such as PAF and alpha1-acid glycoprotein, appear to draw an undescribed picture, so far, of upregulation of a composite systemic anti-inflammatory mechanism in atherosclerotic patients. IL-1ra appears to be a reliable marker of the state of activation of this mechanism. These results may provide a basis for developing new insights into the pathogenesis of the atherosclerotic disease.

Inhibition of leucocyte and platelet adhesion reduces neointimal hyperplasia after arterial injury.

Restenosis following coronary angioplasty is though to result from migration and proliferation of medial smooth muscle cells. However, the factors that initiate this proliferation are still unknown. In a rabbit model of carotid artery injury, we tested the hypothesis that activated platelets and leucocytes might contribute to the development of neointimal hyperplasia. Following arterial injury, rabbits received either no treatment, R15.7, a monoclonal antibody against the leucocyte CD11/CD18 adhesion complex, aurintricarboxylic acid (ATA), a substance that inhibits platelet glycoprotein Ib-von Willebrand factor interaction, or the combination of R15.7 and ATA. After 21 days, the extent of neointimal hyperplasia was evaluated by planimetry on histological arterial sections. The area of neointima averaged 0.51 +/- 0.07 mm2 in control animals and it was significantly reduced by administration of either R15.7 or ATA alone to 0.12 +/- 0.05 and 0.20 +/- 0.01 mm2, respectively (p < 0.05 vs controls for both groups). The animals that received the combination of R15.7 and ATA showed a further reduction in neointimal hyperplasia, as compared to animals that received ATA alone (p < 0.05 vs ATA alone). These data indicate that platelets and leucocytes play an important role in the pathophysiology of neointimal hyperplasia in this experimental model. Interventions that reduce platelet and leucocyte adhesion to vessel wall might have beneficial effects in reducing restenosis following coronary angioplasty.

N-acetyl cysteine attenuates acute lung injury in the rat.

The development of the adult respiratory distress syndrome (ARDS) in the critically ill patient is associated with a significant morbidity and mortality. The pulmonary dysfunction in ARDS is largely secondary to neutrophil-mediated oxidant injury. The purpose of these studies is to examine the effect of the antioxidant N-acetyl cysteine (NAC) on a rodent model of lung injury. We postulated that NAC might attenuate lung injury following intratracheal challenge with endotoxin (lipopolysaccharide; LPS). Male Sprague-Dawley rats were administered NAC systemically either before or after intratracheal administration of LPS. Lung injury was assessed by measuring the transpulmonary leakage of 125I-labeled albumin, pulmonary myeloperoxidase content, bronchoalveolar lavage fluid cell counts, pulmonary lipid peroxidation and histology. NAC administration significantly attenuated the LPS-induced increases in lung permeability (LPS: .24 +/- .08 vs. LPS + NAC: .12 +/- .03, p < .05) and reduced the LPS-dependent increase in lipid peroxidation. However, total and differential bronchoalveolar lavage cell counts and myeloperoxidase content were not affected by NAC pretreatment. Although neutrophil influx was unaffected, neutrophil activation as assessed by surface CD11b expression and chemiluminescence was significantly down-regulated by NAC. Importantly, NAC administration up to 2 h after endotoxin challenge was still able to significantly ameliorate LPS-induced lung injury. Our data suggests that the attenuation of acute lung injury by NAC in our rodent model is related to free radical scavenging and inhibition of the neutrophil oxidative burst, rather than by an effect on inflammatory cell migration. These results suggest novel approaches for therapeutic interventions in acute lung injury.

Radiodetoxified endotoxin-induced tolerance alters monocyte but not neutrophil CD11b and CD18 expression in response to lipopolysaccharide.

OBJECTIVES: To test the hypothesis that pretreatment with radiodetoxified endotoxin (RDE) may mitigate the deleterious effects of subsequent infection, in part by modifying leukocyte adhesion receptor expression, and to investigate the cellular mechanisms of endotoxin tolerance induced by RDE. DESIGN: To assess the effect of RDE pretreatment on mortality from bacterial peritonitis, rats were implanted with an intraperitoneal, barium-fecal inoculum at intervals of 0, 1, 3, and 5 days after RDE injection. Experiments were then conducted to test the effect on leukocyte adhesion receptor expression. Two groups of mice received saline solution, and one group, RDE. After 72 hours, one group received saline solution (saline/saline group), the others, lipopolysaccharide (LPS) (saline/LPS and RDE/LPS groups). Peripheral leukocytes were obtained 1 hour after injection and were analyzed for CD11b and CD18 expression by flow cytometry. SETTING: Laboratory animal study. RESULTS: Survival rates were not improved in rats that were pretreated with RDE 0 and 24 hours before inoculum (0% and 7%, respectively). In rats that were pretreated 72 hours and 120 hours before inoculum, 47% (P < .01) and 60% (P < .01) survived, respectively. CD18 expression on polymorphonuclear leukocytes increased twofold in the RDE/LPS (mean +/- SEM, 300.3 +/- 32.9) and the saline/LPS (mean +/- SEM, 360.4 +/- 59.9) groups compared with controls (mean +/- SEM, 176.4 +/- 18.9) (P < .05). CD11b expression on polymorphonuclear leukocytes increased threefold in the RDE/LPS (mean +/- SEM, 91.3 +/- 8.1) and the saline/LPS (mean +/- SEM, 89.8 +/- 11.4) groups compared with controls (mean +/- SEM, 32.1 +/- 1.8) (P < .05). CD18 expression on monocytes decreased in the saline/LPS group (mean +/- SEM, 134.2 +/- 14.2) and was unchanged in the RDE/LPS group (mean +/- SEM, 200.2 +/- 17.2) compared with controls (mean +/- SEM, 217.6 +/- 16.5) (P < .05). CD11b expression on monocytes decreased in the saline/LPS group (mean +/- SEM, 25.8 +/- 2.2) and was unchanged in the RDE/LPS group (mean +/- SEM, 36.4 +/- 0.9) compared with controls (mean +/- SEM, 39.7 +/- 3.9) (P < .05). CONCLUSIONS: Radiodetoxified endotoxin reduces mortality rates from bacterial peritonitis when given at least 72 hours prior to a bacterial inoculum. Tolerance to subsequent LPS challenge is associated with an abrogation of the reduced peripheral monocyte CD11b and CD18 expression observed in native LPS-stimulated mice but is not associated with changes in polymorphonuclear leukocyte CD11b and CD18 expression. The mechanism of the observed RDE-induced monocyte hyporesponsiveness to LPS and its possible protective effect is uncertain and requires further investigation.

Inhibition by dipyridamole of neutrophil adhesion to vascular endothelium during coronary bypass surgery.

BACKGROUND: Release of reactive oxygen radicals by activated neutrophils and neutrophil adhesion to endothelial cells have been observed after cardiopulmonary bypass. The aim of the present study was to evaluate the effects of preoperative dipyridamole treatment on neutrophil superoxide anion generation and endothelial cell-neutrophil interactions. METHODS: Two groups of patients scheduled for elective coronary artery bypass grafting were randomized to receive oral dipyridamole or a placebo. Nitro blue tetrazolium scores of circulating neutrophils, neutrophil CD11b/CD18 expression, and their adhesion to human umbilical vein endothelial cells were assayed before anesthesia, 30 minutes after the beginning of cardiopulmonary bypass, at the end of bypass, and 60 minutes postoperatively. RESULTS: In both groups, cardiopulmonary bypass resulted in a significant increase in nitro blue tetrazolium scores in circulating neutrophils as well as a significant increase in both neutrophil CD11b/CD18 expression and neutrophil adhesion to endothelial cells. The extent of neutrophil superoxide anion generation was higher in the control group; a significant (p < 0.01) reduction in neutrophil adhesion to endothelial cells was observed 1 hour postoperatively in the dipyridamole group. In 5 patients treated with dipyridamole, the incubation of activated polymorphonuclear leukocytes with adenosine deaminase significantly increased their adhesion to endothelial cells (p < 0.05). CONCLUSIONS: Our study demonstrated that preoperative treatment with oral dipyridamole significantly reduces both neutrophil superoxide anion generation and extent of neutrophil adhesion to endothelial cells after coronary bypass grafting procedures with cardiopulmonary bypass. The mechanism is probably mediated by endogenous adenosine.

Controlled clinical trial to assess the response of recent heroin abusers with chronic hepatitis C virus infection to treatment with interferon alpha-n2b.

BACKGROUND: Chronic infection with hepatitis C virus (HCV) is the most common infectious disease among heroin abusers, but it is recommended that specific treatment with interferon be delayed until at least 6 to 12 months after the end of drug addiction. OBJECTIVE: We investigated the response of heroin abusers to interferon treatment shortly after the end of detoxification treatment with methadone. METHODS: We studied 2 homogeneous groups of white Italian patients with chronic HCV infection: former male heroin abusers and males without a history of drug addiction. Tumor necrosis factor, interleukin-1beta, interleukin-2, activated monocytes, anti-HCV antibodies, HCV RNA, and alanine aminotransferase levels were assessed. Standard treatment was initiated with 5 MU interferon alpha-n2b administered subcutaneously once daily for 8 weeks. Patients with negative HCV-RNA findings at the end of 8 weeks received further treatment with 5 MU TIW subcutaneously for an additional 48 weeks. RESULTS: Thirty of 47 patients in group A (former heroin abusers) and 30 of 30 patients in group B (controls) completed the study. Heroin abusers presented a significantly enhanced response to treatment compared with the controls. After 8 weeks, HCV-RNA test results were negative in 27 of 30 patients in group A (90.0%) and in 25 of 30 in group B (83.3%) (P = NS). Onset of relapse occurred significantly later in heroin abusers (mean [SD], 53 [3] weeks) than in controls (26 [2] weeks) (P < 0.05). Cytokine levels and activated CD11 antigen-expressing monocytes were significantly (P < 0.001) higher in heroin abusers than controls. CONCLUSION: Heroin abusers with chronic HCV infection were successfully treated with interferon alpha-n2b soon after the end of detoxification treatment.

Changes in the expression of leukocyte adhesion molecules throughout the acute phase of myocardial infarction.

Since increased leukocytes within days after the onset of acute myocardial infarction (AMI) may reflect an increased expression of the adhesion molecules necessary for effective endothelial transmigration, we evaluated the expression of adhesion molecules on leukocytes throughout the acute phase of MI. We measured the number of leukocytes and enzymes and the expression levels of CD11a, CD18, very-late-after-activation antigen-4 alpha, intracellular adhesion molecule-1 (ICAM-1) and L-selectin by flow cytometry before and after coronary intervention, and at 6, 12, 18, 48 and 72 hours of MI in 5 patients (AMI group). As controls, we measured these parameters in 5 patients who had been diagnosed with angina pectoris and underwent coronary intervention (AP group). In the AMI group the expression of monocyte CD11a was significantly increased after 6 hours, and CD18 and ICAM-1 expression were also significantly increased after 12 hours, whereas that of monocyte L-selectin was increased after 72 hours. In addition, the increased monocyte CD11a was accompanied by an increased number of monocytes and a greater expression of CD11a per cell in the AMI group. In conclusion, since CD11a and CD18 are expressed on the cell surface as a heterodimer and ICAM-1 is a ligand for CD11a/CD18, their increased expression may contribute to their adhesion to endothelium in ischemic regions and may lead to the formation of microaggregates.

Comparative study on age-dependent development of surface receptors on peripheral blood lymphocytes in children and young nonhuman primates (marmosets).

General conformity was found concerning age-dependent changes in the major subsets (CD4, CD8, CD2, CD20) and the adhesion molecules CD11a and CD29 on peripheral blood lymphocytes in children and young marmosets (Callithrix jacchus). Differences exist in the expression of the surface receptors CD45RA and CD56. Taking the total number of white blood cells into account, an age-related increase in the absolute numbers of peripheral blood lymphocytes was found in marmosets whereas in children, an age-dependent decrease was observed. The definition of reference ranges for different stages of maturation in children and young marmosets may serve as a basis on which comparative risk assessment of possible effects on lymphocyte subsets after pre- or perinatal drug exposure can be estimated.

Binding of monocytes from normolipidemic hyperglycemic patients with type 1 diabetes to endothelial cells is increased in vitro.

Increased endothelial binding and emigration of monocytes play a dominant role in the pathogenesis of atherosclerosis in diabetes mellitus. Previous studies revealed that hyperlipidemia correlates with monocyte binding in vitro. The aim of this study was to characterize the monocyte-endothelial interaction of leucocytes of hyperglycemic patients with type 1 diabetes but lacking hyperlipidemia. We isolated monocytes from healthy controls and normolipidemic type 1 diabetes patients with elevated levels of HbA1c and quantified monocyte binding by an immunoilluminometric cell adhesion assay. Purity of isolated monocytes was at least 98%. Endothelial binding of monocytes from patients with type 1 diabetes was found to be significantly increased compared to controls (19.2 +/- 3.9% vs. 14.9 +/- 3.5%). This difference of monocyte binding remained unchanged if the endothelial cells were stimulated with 27.7 mmol/l glucose for seven days prior to adhesion studies (31.5 +/- 4.9% in diabetes patients vs. 25.8 +/- 4.1% in controls) whereby monocyte binding markedly increased under these hyperglycemic conditions. Furthermore, an increased CD11b expression could be demonstrated on monocytes of normolipidemic hyperglycemic type 1 diabetes patients. Thus, we suggest that hyperglycemia per se may contribute to increased monocyte binding to endothelial cells by promoting leucocyte integrin expression. Recently performed studies of our group strengthen the hypothesis that this monocyte activation is mediated by stimulation of the beta-isoform of proteinkinase C.

Ca2+ response in neutrophils after exposure to bacterial N-formyl-methionyl-leucyl-phenylalanine: delayed response in ulcerative colitis.

OBJECTIVE: In acute stages of ulcerative colitis (UC), neutrophils migrate from the circulation into inflamed colonic tissue, initiated by yet unknown stimuli. The bacterial peptide N-formyl-methionyl-leucyl-phenylalanine (FMLP) is a component of the surface membrane of colonic bacteria such as Escherichia coli and stimulates Ca2+ influx into neutrophils, reflecting the fact that ionized calcium is an important secondary messenger for several neutrophil functions, including locomotion, phagocytosis and free oxygen radical production. Recent studies have revealed that Ca2+ dependent ICAM-1/beta 2-integrin mediated neutrophil migration is impaired in UC patients. The aim of the present work was to study the influx of Ca2+ into peripheral blood neutrophils of UC patients after exposure to FMLP and after binding of either beta 2-integrins or intercellular adhesion molecule-1 (ICAM-1). METHODS: The relative intracellular Ca2+ levels ([Ca2+]i ) were measured spectrofluorometrically in neutrophils isolated from eight UC patients and eight controls. The cells were exposed to 1 nm FMLP, 5 pm free ICAM-1, or antibodies binding ICAM-1 or the beta 2-integrins CD11a, CD11b, CD11c and CD18. RESULTS: A pronounced increase in [Ca2+]i was observed by exposure of cells to FMLP, and neutrophils from UC patients showed a consistent and significant delayed response as compared to cells from control subjects (P < 0.01). Antibody mediated cross-linking of CD18 triggered a small but detectable increase in [Ca2+]i, which did not differ between patients and controls. CONCLUSION: A delayed response to bacterial peptides appears to be a phenotypic trait for neutrophils of UC patients. A connection between FMLP stimulated Ca2+ influx and CD11/CD18 upregulation is discussed.

Abrogation of surgery-induced decline in circulating dendritic cells by subcutaneous preoperative administration of IL-2 in operable cancer patients.

Surgery-induced immunosuppression is characterized by a decline in lymphocyte count, particularly T lymphocyte number. In addition, preliminary studies have shown that the postoperative period is also characterized by a decline in the number of circulating dendritic cells (DC), whose fundamental anticancer role has been recently demonstrated. Previous studies had already shown that the preoperative injection of IL-2 may completely abrogate surgery-induced lymphocytopenia, whereas its eventual influence on DC system during the perioperative period is still unknown. The present study was performed to evaluate the influence of IL-2 preoperative immunotherapy on the perioperative changes in circulating DC number in patients affected by colorectal cancer. The study included 14 consecutive patients, who were randomized to be treated with or without IL-2 presurgical immunotherapy (12 million IU/day for 3 days subcutaneously). Circulating immature and mature cells were evaluated before surgery and at days 3 and 7 of the postoperative period. The detection was made by FACS using monoclonal antibodies against CD123 and CD11c to recognize immature and mature DC, respectively. Surgery induced a significant decline in the mean number of both immature and mature DC. The pre-surgical administration of IL-2 completely abrogated surgery-induced decline in immature DC cell amount. Moreover, mature DC mean number was diminished only at day 3 of the postoperative period, since the value observed at day 7 was not significantly lower than that found before surgery. This preliminary study shows that surgery-induced immunosuppression is characterized also by a significant decline in the mean number of both immature and mature DC. Moreover, this study would suggest that the preoperative immunotherapy with IL-2 may counteract surgery-induced failure of DC system. Because of the fundamental antitumor role of DC, this evidence could have a prognostic impact on the clinical course of the neoplastic disease.

The state of leukocyte adhesiveness/aggregation in the peripheral blood of patients with type 2 diabetes and ischemic vascular disease.

White blood cells have a potential role in the pathogenesis of vasculopathy in diabetic patients. We studied the circulating peripheral blood in a cohort of patients with documented ischemic heart or brain disease with and without type 2 diabetes by means of image analysis and flow cytometry. Our study showed that the state of leukocyte adhesiveness/aggregation is slightly increased in those who had concomitant diabetes but that there was no difference regarding the expression of CD11b/CD18 and CD62L antigens on the surface of the peripheral blood white blood cells. The finding of a significantly increased number of white blood cells in the peripheral blood of patients with ischemic vascular diseases is important insofar as it is associated with a poorer prognosis.

Bound and soluble adhesion molecule and cytokine levels in patients with severe burns.

We measured endotoxins, inflammatory cytokines and soluble adhesion molecules in the blood of 17 severe burn patients to determine the involvement of these factors in the pathophysiology of severe burns. All seventeen patients had burns with a total burn surface area of 20% or more and a burn index of 15% or more. Endotoxin was measured by an endotoxin-specific assay and tumor necrosis factor-alpha, interleukin 6 and interleukin 8 and soluble adhesion molecules were measured by enzyme-linked immunosorbent assay. CD11a, CD11b and CD18, measured by flow cytometry, were elevated in the non-surviving group, the septic shock group and the multiple organ dysfunction syndrome group, suggesting a close connection between these adhesion molecules and burns complicated by infection. Soluble adhesion molecules were found to indirectly reflect the level of endothelial cell adhesion molecules, suggesting that inflammatory cytokines may also be involved in their production.

Measurement of CD11/CD18 integrin expression on the polymorphonuclear cell surface after incubation with synthetic vascular prostheses.

Polymorphonuclear (PMN) cell activation in the presence of synthetic vascular grafts was studied by using flow cytometry to measure CD11/CD18 leukocyte adhesion molecule expression at the cell surface. Polymorphonuclear cells isolated from the blood of 10 healthy human donors were incubated with six knitted polyester vascular prostheses (Vasculour II, Albumin-Coated Graft, Triaxial, Gelatin-Impregnated Gelseal, Dialine I, and Bovine Collagen-Impregnated Dialine II) for 60 min at 37 degrees C. The authors' study demonstrated that CD11/CD18 integrin expression varies among donors for a given vascular prosthesis, and that each donor has his or her own pattern of responsiveness toward synthetic vascular grafts. The current study indicates that PMN activation measured by CD11/CD18 integrin expression is a sensitive method of measuring the blood compatibility of a given foreign surface for a given patient.

Modulation of CD11b/CD18 on monocytes and granulocytes following hemodialysis membrane interaction in vitro.

We studied the generation of CD11b/CD18 mobilizing factors in serum after incubation with dialysis membrane fragments of different chemical composition. We also evaluated the relative importance of the alternative and classical pathways of the complement system in the generation of such factors. Monocytes and granulocytes from healthy blood donors were incubated in normal human serum (NHS) and in NHS that had been preincubated with Cuprophan (CU) membrane (NHS-CU), Hemophan (HE) (NHS-HE) or polysulfone (PS) (NHS-PS). NHS-CU caused the highest up-regulation of the CD11b/CD18 receptor on monocytes and granulocytes. The rank in capacity to mobilize CD11b/CD18 on granulocytes was CU > HE > PS (p < 0.001), CU > HE (p < 0.05) and HE > PS (p < 0.001). The rank in capacity to mobilize CD11b/CD18 on monocytes was CU > HE > PS (p < 0.001), CU > HE (p < 0.05) and HE > PS (p < 0.01). NHS-PS induced a lower up-regulation of CD11b/CD18 compared to NHS which indicates that serum factors with the ability to mobilize the CD11b/CD18 receptor on monocytes and granulocytes are deposited on or absorbed by PS. In order to study the relative contribution of the alternative and classical pathways of the complement system in the generation of CD11b/CD18 mobilizing factors in serum, three different serum preparations (1. both pathways intact. 2. only the alternative intact and 3. only the classical pathway intact) were used. The CU membrane activated the classical pathway to a larger extent than the PS membrane (p < 0.01). When only the alternative pathway was intact no difference in the generation of CD11b/CD18 mobilizing factors between the CU and PS membranes was observed. These studies show that CD11b/CD18 mobilizing serum factors are generated after incubation with CU membranes and that such factors are probably adsorbed by PS. The classical pathway of complement activation seems to contribute to the generation of CD11b/CD18 mobilizing factors in serum.