Flow cytometric determination of CD11b upregulation in vivo

Leishmania major surface components and DKK1 signalling via LRP6 promote migration and longevity of neutrophils in the infection site

Background

Host-related factors highly regulate the increased circulation of neutrophils during Leishmania infection. Platelet-derived Dickkopf-1 (DKK1) is established as a high-affinity ligand to LRP6. Recently, we demonstrated that DKK1 upregulates leukocyte-platelet aggregation, infiltration of neutrophils to the draining lymph node and Th2 differentiation during Leishmania infection, suggesting the potential involvement of the DKK1-LRP6 signalling pathway in neutrophil migration in infectious diseases.

Results

In this study, we further explored the potential role of DKK1-LRP6 signalling in the migration and longevity of activated neutrophils in the infection site using BALB/c mice with PMNs deficient in LRP6 (LRP6NKO) or BALB/c mice deficient in both PMN LRP6 and platelet DKK1 (LRP6NKO DKK1PKO). Relative to the infected wild-type BALB/c mice, reduced neutrophil activation at the infection site of LRP6NKO or LRP6NKO DKK1PKO mice was noted. The neutrophils obtained from either infected LRP6NKO or LRP6NKO DKK1PKO mice additionally showed a high level of apoptosis. Notably, the level of LRP6 expressing neutrophils was elevated in infected BALB/c mice. Relative to infected BALB/c mice, a significant reduction in parasite load was observed in both LRP6NKO and LRP6NKO DKK1PKO infected mice. Notably, DKK1 levels were comparable in the LRP6NKO and BALB/c mice in response to infection, indicating that PMN activation is the major pathway for DKK1 in promoting parasitemia. Parasite-specific components also play a crucial role in modulating neutrophil circulation in Leishmania disease. Thus, we further determine the contribution of Leishmania membrane components in the migration of neutrophils to the infection site using null mutants deficient in LPG synthesis (Δlpg1- ) or lacking all ether phospholipids (plasmalogens, LPG, and GIPLs) synthesis (Δads1- ). Relative to the WT controls, Δads1- parasite-infected mice showed a sustained decrease in neutrophils and neutrophil-platelet aggregates (for at least 14 days PI), while neutrophils returned to normal in Δlpg1- parasite-infected mice after day 3 PI.

Conclusion

Our results suggest that DKK1 signalling and Leishmania pathogen-associated molecular patterns appear to regulate the migration and sustenance of viable activated neutrophils in the infection site resulting in chronic type 2 cell-mediated inflammation.

Hyperbaric oxygen reduces inflammation, oxygenates injured muscle, and regenerates skeletal muscle via macrophage and satellite cell activation

Hyperbaric oxygen treatment (HBO) promotes rapid recovery from soft tissue injuries. However, the healing mechanism is unclear. Here we assessed the effects of HBO on contused calf muscles in a rat skeletal muscle injury model. An experimental HBO chamber was developed and rats were treated with 100% oxygen, 2.5 atmospheres absolute for 2 h/day after injury. HBO reduced early lower limb volume and muscle wet weight in contused muscles, and promoted muscle isometric strength 7 days after injury. HBO suppressed the elevation of circulating macrophages in the acute phase and then accelerated macrophage invasion into the contused muscle. This environment also increased the number of proliferating and differentiating satellite cells and the amount of regenerated muscle fibers. In the early phase after injury, HBO stimulated the IL-6/STAT3 pathway in contused muscles. Our results demonstrate that HBO has a dual role in decreasing inflammation and accelerating myogenesis in muscle contusion injuries.

Clinical and Biomaterial Evaluation of a new Condensed Dual-Function Extracorporeal Circuit in Reoperation for Coronary Artery Bypass Surgery

Purpose

This prospective, randomized study compared the clinical performance of three types of circuits: a newly introduced, fully-coated, interchangeable open-closed circuit with a dual configuration (hard shell with a bypass shunt), reduced length, and reduced prime of less than 800 cc (CondECC); a completely coated circuit (ECC); and a similar uncoated, open circuit with standard length and prime (CONT).

Methods

75 patients undergoing reoperation for coronary revascularization were randomly allocated into three groups (N=25): Group 1: CondECC with shortened tubing, components and an open-closed configuration of low priming volume with a centrifugal pump and a shunt which bypassed the reservoir for closed configuration; Group 2: ECC with a roller pump and hard-shell reservoir; Group 3: CONT. Blood samples for CBC, inflammatory mediators [Interleukin-2 (IL-2), Complement-3a (C3a)] and flow cytometry (CD11 b/CD18) were collected after induction (T1) and heparin administration (T2), 15 min after cardiopulmonary bypass (CPB) (T3), before cessation of CPB (T4), 15 min after reversal (T5), and the first postoperative day (T6).

Results

Leukocyte counts demonstrated significant increases at T4, T5 in CONT but remained stable in ECC and CondECC (p<0.05). Platelets were preserved better at T4, T5 in both ECC and CondECC study groups (p<0.05). IL-2 and C3a levels were significantly lower at T3, T4, T5 in CondECC and T4, T5 in ECC (p<0.05). Blood protein adsorption analysis demonstrated increased amount of microalbumin on CONT fibers (p<0.05).

Conclusions

The CondECC is a flexible, dual-function, open/closed configuration system that was easy to use, safe and achieved better biocompatibility when compared to coated and uncoated conventional circuits.

Clinical effects of leukofiltration and surface modification on post-cardiopulmonary bypass atrial fibrillation in different risk cohorts

Objective. A manifestation of inflammatory injury to the heart, atrial fibrillation (AF), ranks among the most frequent and potentially life-threatening post-operative complications. Methods. In a prospective randomized study, 120 patients undergoing CABG were allocated into two groups (N = 60): Group 1- Polymethoxyethylacry late-coated circuits + Leukocyte filters (Terumo,USA); Group 2: Control:Uncoated circuits (Terumo,USA). Each group was further divided into three subgroups (N = 20) with respect to low (Euroscore 0—2), medium (3—5) and high (6+) risk patients. Results. Serum IL-2 levels were significantly lower in the study group at T4 and T5 (p < 0.01). C3a levels showed significant differences in the leukofiltrated group at T4 and T5 (p < 0.05). CPKMB levels demonstrated well-preserved myocardium in the leukofiltration group, post-operatively. AF incidence was 10% (2 patients) in the study and 35% (7 patients) in the control cohorts (p < 0.05). Phagocytic capacity on fibers in filtered patients was significantly lower. Conclusion: Leukofiltration and coating significantly reduce the incidence, ventricular rate, and duration of AF after CABG via modulation of systemic inflammatory response and platelet preservation in high risk groups. Perfusion (2007) 22, 279—288.

Impact of the intensity of microemboli on neurocognitive outcome following cardiopulmonary bypass

BACKGROUND

This study aimed to determine whether there was any association between the intensity of intraoperative gaseous microembolic signals (GME), neuropsychological testing and clinical outcome in high-risk patients undergoing coronary artery surgery (CABG).

METHODS

Over a 6-month period, GME activity was monitored in 102 Euroscore 6+ patients during cardiopulmonary bypass (CPB) with a conventional 32-micron arterial filter by non-invasive, real-time ultrasonic device. Cognitive tests; line bisection, the Stroop test, finger tapping, and the Rey Auditory Verbal Learning Test were performed at baseline, postoperative one week and postoperative one month.

RESULTS

The distribution of GME activity showed that there were three groups of patients: >500 total emboli (n = 38); 250 to 500 emboli (n = 30) and <250 emboli (n = 34) at a detection level of 2% of the circuit diameter on the arterial side. Line bisection, the Stroop test and finger tapping were impaired significantly in >500 emboli patients versus control (<250 emboli) in postoperative week one, but resolved in one month.

CONCLUSIONS

Correlation between intraoperative GME intensity and neurocognitive tests suggests that the level of GME might have a role in determining the psychological outcome after CABG with CPB.

Clinical evaluation of leukocyte filtration as an alternative anti-inflammatory strategy to aprotinin in high-risk patients undergoing coronary revascularization

PURPOSE

The use of aprotinin in cardiac surgery is associated with overriding safety concerns. Therefore, there is increased research on alternatives. This study investigated the relative benefits of strategic leukofiltration on polymer-coated extracorporeal circuits (ECC), aprotinin, and combined therapy in high-risk patients.

METHODS

Eight hundred and seventy-five patients (EuroSCORE 6+) undergoing coronary revascularization over a 4-year period were prospectively randomized to one of four perfusion protocols: Group 1: polymethoxyethylacrylate (PMEA)-coated circuits + leukocyte filters (n = 214); Group 2: uncoated ECC + full Hammersmith aprotinin (n = 212); Group 3: PMEA-coated ECC + leukofilters + full Hammersmith aprotinin (n = 199); and Group 4: control-no treatment (n = 250). Blood samples were collected at times T1: following the induction of anesthesia; T2: following heparin administration; T3: 15 min after cardiopulmonary bypass (CPB); T4: before cessation of CPB; T5: 15 min after protamine reversal; and T6: in the intensive care unit.

RESULTS

The serum interleukin-2 levels were significantly lower at T3, T4, and T5 in all study groups. C3a levels were significantly lower at T3. Creatine kinase MB and lactate levels demonstrated well-preserved myocardia in both leukofiltration groups (P < 0.05). Neutrophil CD11b/CD18 levels were significantly lower for all study groups. Postoperative bleeding and respiratory support time were lower in all study groups.

CONCLUSION

Leukofiltration on coated circuits significantly reduced bleeding and inflammatory response related to CPB with no adverse effects, and may be a possible alternative to pharmacological intervention.

Analysis of the temperature affects on leukocyte surface antigen expression

Flow cytometric analysis of leukocyte surface antigens has been used to characterize infectious and septic processes in patients. We wanted to investigate how the sampling and processing temperature, the anticoagulant used, and the storage of the sample influence leukocyte immunophenotyping. Four blood samples, two using acid citrate dextrose and two using heparin as an anticoagulant, were taken from five intensive-care unit patients with severe sepsis and five healthy volunteers. The samples were collected, stored, and processed either at +4°C or at room temperature (RT). The samples were processed for flow cytometric analysis within 1  hr of collection or after 6 or 24  hr storage. The surface antigens of interest were neutrophilic CD11b and CD64, monocytic CD11b, CD14, CD40, CD64, CD80 and HLA-DR, and lymphocytic CD69 (separately in CD4+ and CD8+ T cells, B cells, and natural killer cells). The fluorescence intensities were higher at RT than at +4°C. During storage the intensities increased at RT, but at +4°C there were only minor changes. The effects were similar with both anticoagulants studied. According to our results, flow cytometric analysis of leukocyte surface antigen expressions should be performed using +4°C temperature throughout the process and within 6  hr.

Perioperative blood conservation strategies in pediatric patients undergoing open-heart surgery: impact of non-autologous blood transfusion and surface-coated extracorporeal circuits

BACKGROUND

The aim of this study was to explore the relative clinical and biomaterial effects of blood transfusions (Tx) and novel low-prime, surface-coated circuitry on perioperative outcome in a pediatric population undergoing cardiac surgery with cardiopulmonary bypass (CPB).

METHODS

Over a 12-month period, 80 patients weighing >10 kg undergoing ventricular septal defect (VSD) repair with CPB were prospectively randomized into two groups according to the type of CBP circuit used, then each randomized group was enrolled into two groups again, according to the need for transfusion (N=20): Group 1- Tx-free procedures on low-prime, surface-coated extracorporeal circuitry (FX05, Terumo); Group 2- procedures requiring Tx on coated circuitry; Group 3- Tx-free procedures with standard uncoated circuitry (D902, Sorin); Group 4 (Control)- procedures requiring Tx on uncoated circuitry. Blood samples were collected at baseline (T1), at the end of the CPB (T2) and 24 h (T3) postoperatively. rSO(2) desaturation risk score >6000 (Invos, Somanetics) was calculated by multiplying rSO(2) <50% by time.

RESULTS

IL-6 levels (pg/ml) were significantly lower in Groups 1 and 3 versus control at T2 (13±4; 17±5 versus 33±8; p<0.05). CD11b/CD18 levels (%) were significantly lower in Group 1 (12±4) versus control (25±8) at T2 (p<0.05). Respiratory support time (h) was significantly less in Group 1 (11.4±6) versus control (19.8±7) (p<0.05). rSO(2) desaturation risk >6000 (%) was 15.7±9 in Group 1 and 26.8±11 in control (p<0.05).

CONCLUSION

Allogenic Tx amplifies the CPB-related inflammatory response. It is feasible to do congenital procedures safely without Tx for patients weighing >10 kg by using combined blood management strategies.

Clinical performance and biocompatibility of hyaluronan-based heparin-bonded extracorporeal circuits in different risk cohorts

This prospective randomized study compares novel hyaluronan-based heparin-bonded circuits vs. uncoated controls across EuroSCORE patient risk strata including biomaterial evaluation. Over a two-year period, 90 patients undergoing coronary artery bypass grafting were prospectively randomized to one of the two perfusion protocols: Group 1 was treated with hyaluronan-based heparin-bonded preconnected circuits (Vision HFO-GBS, Gish, CA, USA) and Group 2 with identical uncoated controls. Each group was composed of three subgroups (n=15) with respect to preoperative evaluation of low (EuroSCORE 0-2), medium (3-5) and high (6+) risk patients. Blood samples were collected after induction (T1) and heparinization (T2), 15 min after cardiopulmonary bypass start (T3), before cessation of CPB (T4), 15 min after reversal (T5), and the first postoperative day (T6). In high-risk patients, platelet counts demonstrated significant preservation at T4, T5 and leukocyte counts were lower at T5 in hyaluronan group (P<or=0.05 vs. control). C3a (ng x ml(-1)) levels were significantly lower at T3 (0.2+/-0.04 vs. 0.31+/-0.05), T4 (0.25+/-0.04 vs. 0.51+/-0.05), T5 (0.38+/-0.04 vs. 0.56+/-0.05) and interleukin-6 (pg x ml(-1)) at T4 (91+/-18 vs. 124+/-20), T5 (110+/-20 vs. 220+/-25) in coated group vs. control (P<or=0.05). Protein desorption (microalbumin) on fibers (mg x mm(-3)) was less in hyaluronan vs. control groups (P<or=0.05). Hyaluronan coating reduced platelet adhesion and cell adsorption, and modulated inflammatory response in high-risk patients.

Clinical evaluation of minimized extracorporeal circulation in high-risk coronary revascularization: impact on air handling, inflammation, hemodilution and myocardial function

Objective: We examined intraoperative microembolic signals (GME), inflammatory response, hemolysis, perioperative regional cerebral oxygen saturation (rSO2), myocardial protection and desorbed protein amount on oxygenator fibers in high-risk patients undergoing coronary revascularization (CABG) with minimized and conventional cardiopulmonary bypass (CPB). Methods: Over a ten-month period, 40 Euroscore 6+ patients undergoing CABG were prospectively randomized to one of the two perfusion protocols (N=20): Group 1: minimized extracorporeal circuits (Mini-CPB) (ROCsafe MPC, Terumo, Ann Arbor, MI, USA) and Group 2: conventional extracorporeal circuits (CECC) (Capiox SX18, Terumo, USA). Serum creatinine kinase-MB (CKMB), free hemoglobin, interleukin-6 (IL-6) and C3a levels were measured. Blood samples were collected at T1: following induction of anesthesia; T2: thromboelastography control; T3:15 min after commencement of CPB; T4: before cessation of CPB; T5: 15 min after protamine reversal and T6: ICU. Results: Serum IL-6 levels were significantly lower in the Mini-CPB group at T4 and T5 and C3a levels were significantly less in the Mini-CPB group at T3, T4 and T5 vs. CECC (p<0.01). CKMB levels in coronary sinus blood demonstrated well preserved myocardium in the Mini-CPB group. Percentage expression of neutrophil CD11b/CD18 levels were significantly lower in the Mini-CPB group at T4 and T5 (p<0.05). There were no significant differences in air handling characteristics or free plasma hemoglobin levels in either circuit. rSO2 measurements were significantly better at T3 and T4 in the Mini-CPB vs. CECC (p<0.05) and always higher in the Mini-CPB during follow-up. Blood protein adsorption analysis of oxygenator membranes demonstrated a significantly increased amount of microalbumin on CECC fibers (p<0.05). Conclusion: Mini-CPB provided a comfort and safety level similar to conventional control via satisfactory air handling, attenuated inflammatory response and hemodilution, with a better clinical outcome in patients undergoing high-risk CABG.

Hepatic neutrophil activation during reperfusion may not contribute to initial graft function after short cold ischemia in human liver transplantation

BACKGROUND

Experimental models of hepatic ischemia/reperfusion injury have implicated a pathophysiologic role for neutrophils in subsequent hepatocellular damage. In human liver transplantation, however, the effect of reperfusion-induced neutrophil activation on initial graft function is not clear.

METHODS

In 38 patients undergoing liver transplantation, neutrophil CD11b and L-selectin expression, neutrophil count, and plasma lactoferrin levels were measured. To assess changes within the graft during initial reperfusion, samples of blood entering and leaving the graft were obtained simultaneously, and transhepatic ratio calculated (hepatic vein/portal vein; 1 denotes no change, <1 a decrease, and >1 an increase across the liver). Graft steatosis, postoperative liver function, and outcome were recorded. Associations between neutrophil activation markers and outcome measures were evaluated.

RESULTS

Substantial hepatic neutrophil activation occurred during initial reperfusion, demonstrated by concomitant L-selectin shedding and CD11b upregulation (transhepatic ratios 0.9 [0.7-1.0]; 1.4 [0.9-1.9]; both P < .001; portal vs hepatic vein]. Simultaneously, hepatic neutrophil sequestration and lactoferrin release occurred (0.3 [0.2-0.5]; 1.7 [1.3-3.4]; both P < .001). Neither cold ischemic time (CIT; median 5 hours 36 minutes) nor hepatic neutrophil activation during reperfusion predicted early graft function, nor was there any association between CIT and neutrophil activation.

CONCLUSIONS

Despite short CIT, extensive graft neutrophil activation and sequestration occurred. This, however, was not associated with impaired early graft function, suggesting short CIT may protect against severe neutrophil-mediated injury.

Monocyte CD14 and soluble CD14 in predicting mortality of patients with severe community acquired infection

Monocyte membrane CD14 (mCD14) and soluble CD14 (sCD14) both associate with poor outcome in sepsis. Because the value of combined use of the markers is unknown we measured both in patients with severe community acquired infections. The study comprised 142 acutely ill patients with community acquired pneumonia and/or blood culture-positive sepsis. Expression of mCD14 was measured, on admission to hospital, by whole blood flow cytometry and sCD14 by ELISA. There was no significant correlation between mCD14 and sCD14. Patients in the lowest tertile of mCD14 were 9.79 times (95% CI 1.31- >50, p =0.006) more likely to die than patients in the middle/highest tertiles. Survival rates in the highest and middle/lowest tertiles of sCD14 levels were comparable. After stratification by sCD14, patients in the lowest tertile of mCD14 were 14.4 times (95% CI 1.90-39.44) more likely to die than patients in the middle/highest tertiles. A significant positive correlation was detected between C-reactive protein and sCD14 levels, providing evidence that sCD14 may serve as an acute phase reactant. In conclusion, low monocyte mCD14 level, unlike the concurrent sCD14 level, predicts 28-d mortality in patients with community acquired infections.

Endogenous protease inhibitor uptake within the graft during reperfusion in human liver transplantation

BACKGROUND

In experimental liver transplantation, endogenous protease inhibitors alleviate ischemia-reperfusion (I/R) injury by inhibiting proteolysis and by direct anti-inflammatory actions. We described the kinetics of endogenous protease inhibitors and explored their anti-inflammatory potential during reperfusion and their effects on graft function in human liver transplantation.

METHODS

We measured circulating levels of protease inhibitors (secretory leukocyte proteinase inhibitor, SLPI; tissue inhibitor of metalloproteinases-1, TIMP-1) and proteolytic enzymes (elastase; matrix metalloproteinase-9, MMP-9) with ELISA, and neutrophil and monocyte CD11b and L-selectin expression with flow cytometry during liver transplantation in ten patients. To assess changes within the graft during reperfusion, blood samples from portal and hepatic veins were obtained simultaneously.

RESULTS

Circulating SLPI and TIMP-1 levels decreased during surgery. During initial reperfusion, the transhepatic SLPI gradient was -27 (-35 to -22) ng/ml, P = 0.005, and TIMP-1 -510 (-636 to -362) ng/ml, P = 0.005, indicating graft protease inhibitor uptake. Concomitantly, hepatic phagocyte activation and sequestration as well as elastase and MMP-9 release into the circulation occurred. The transhepatic SLPI gradient correlated with postoperative liver enzymes (ALT R = -0.648, P = 0.043; ALP R = -0.661, P = 0.038; bilirubin R = -0.821, P = 0.004; GGT R = -0.648, P = 0.043).

CONCLUSIONS

The results suggest a relative shortage of protease inhibitors within the liver during reperfusion, which may contribute to the development of graft injury.

Hepatic IL-8 release during graft procurement is associated with impaired graft function after human liver transplantation

In experimental models, brain death induces inflammatory cascades, leading to reduced graft survival. Thus far, factors prior to graft preservation have gained less attention in clinical setting. We studied pre-preservation inflammatory response and its effects on graft function in 30 brain dead liver donors and the respective recipients. Before donor graft perfusion, portal and hepatic venous blood samples were drawn for phagocyte adhesion molecule expression and plasma cytokine determinations. Donor intensive care unit stay correlated with donor C-reactive protein (R = 0.472, p = 0.013) and IL-6 (R = 0.419, p = 0.026) levels, and donor (R = 0.478, p = 0.016) and recipient gamma-glutamyl transferase (R = 0.432, p = 0.019) levels. During graft procurement, hepatic IL-8 release was observed in 17/30 donors. Grafts with hepatic IL-8 release exhibited subsequently higher alkaline phosphatase [319 (213-405) IU/L vs. 175 (149-208) IU/L, p = 0.006] and bilirubin [101 (44-139) micromol/L vs. 30 (23-72) micromol/L, p = 0.029] levels after transplantation. Our findings support the concept that inflammatory response in the brain dead organ donor contributes to the development of graft injury in human liver transplantation.

Expression of CD11b/CD18 adhesion molecules on circulating phagocytes-a novel aid to diagnose infection in patients with cancer

GOALS OF WORK

No blood marker available to date is useful for distinguishing infection-related from neoplasm-related fever. We evaluated the expression of the peripheral blood phagocyte CD11b/CD18 adhesion molecule complex for this purpose.

MATERIALS AND METHODS

Neutrophil and monocyte CD11b/CD18 expression was assessed in two cohorts of patients with advanced solid cancer (n = 120) and in healthy controls (n = 63). The cancer series included 89 patients with verified infection, 23 without infection, and eight with neoplastic fever. CD11b/CD18 expression was measured using flow cytometry, and serum C-reactive protein (CRP) concentration was determined with immunoturbidimetric assay.

RESULTS

Cancer patients with infection had higher blood neutrophil and monocyte CD11b/CD18 expression levels than patients with neoplastic fever, those with advanced cancer without infection, or healthy controls (p < 0.01 for all analyses). High CD11b/CD18 values were measured exclusively in individuals diagnosed with infection. Receiver-operating characteristic area under the curve (AUC) for neutrophil and monocyte CD11b/CD18 expression for the discrimination of infection from neoplastic fever was 0.80 (95% CI, 0.70 to 0.88), which was superior (p = 0.039 and p = 0.049, respectively) to serum CRP on admission (AUC 0.51, 0.40 to 0.62).

CONCLUSIONS

Peripheral blood phagocytic cell CD11b/CD18 expression is useful for making a differential diagnosis between infection and neoplasm-related fever in cancer patients.

Novel CARD15/NOD2 mutations in Finnish patients with Crohn's disease and their relation to phenotypic variation in vitro and in vivo

BACKGROUND

Three mutations (R702W, G908R, and 1007fs) of the CARD15/NOD2 gene associate with Crohn's disease (CD). Despite a strong linkage of CD to the inflammatory bowel disease (IBD) 1 region, only 16% of the Finnish CD patients carry 1 of these 3 mutations, pointing to the possibility of yet undetected founder mutations in the genetically isolated Finns. The aim of this study was to screen for CARD15 mutations in Finnish CD patients and to assess their functional consequences and relation to clinical phenotype.

METHODS

We performed CARD15 mutation screening in 240 CD probands. For functional studies, blood mononuclear cells were cultured alone or with muramyl dipeptide (MDP) and IL-8 levels were determined.

RESULTS

We identified 30 different variants, including 12 new ones. Allele frequencies for the R702W, G908R, and 1007fs mutations were 3.3%, 0.4%, and 4.8%, respectively. The 1007fs variant was the only 1 associated significantly with CD. Five novel variants (R38M, W355X, P727L, W907R, R1019X) were found in 5 patients. The biochemical nature of these new mutations, data obtained by cross-species comparisons, as well as low IL-8 production favors their pathogenic role. All 5 patients with novel mutations presented a complicated form of ileal or ileocolonic disease.

CONCLUSIONS

In conclusion, we identified 5 novel CARD15 mutations with an apparent pathophysiological role, but could not identify a putative Finnish founder mutation. It is still possible that regulatory mutations present in the flanking or intronic areas of the CARD15 gene contribute to the genetic susceptibility of CD. Homozygosity or compound heterozygosity for CARD15 gene mutations must be considered especially in complicated CD patients.

A novel modification of a flow cytometric assay of phosphorylated STAT1 in whole blood monocytes for immunomonitoring of patients on IFN alpha regimen

We explored whether episodes stimulating leucocytes in vivo could be tracked from whole blood samples by monitoring activation of STAT1 by flow cytometry. The method was tested in hepatitis C patients (n = 9) that were on interferon (IFN)alpha regimen. CD14+ monocytes responded strongly to IFNalpha/gamma being sensitive indicators for recent immune activation. At 45 min after s.c. IFNalpha 91% of monocytes were phosphorylated STAT1+. The frequency of responding cells decreased to a base level within 6 h. Monocytes, however, had a long-term deficient phosphorylated STAT1 response to IFNalphain vitro that in patients on standard IFNalpha regimen lasted for 48 h. In patients on pegylated IFNalpha the phosphorylated STAT1 response was completely absent. We conclude that whole blood analysis of STAT1 activation by flow cytometry is applicable to monitor immune cells in patient material.

Conformational activation of CD11b without shedding of L-selectin on circulating human neutrophils

Membrane-activated complex 1 (Mac-1; CD11b/CD18) is a beta(2) integrin implicated in the pathophysiology of neutrophil-mediated tissue injury whose functional capacity is determined by stimulus-induced conformational activation rather than up-regulation. Mac-1 up-regulation and conformational activation, together with shedding of L-selectin, are reported after in vitro neutrophil activation. However, their regulation on circulating human neutrophils during acute inflammation is unclear. Using flow cytometry, we investigated neutrophil expression of Mac-1, its activation-reporter neo-epitope CBRM1/5, and L-selectin during the inflammatory stimulus of cardiac surgery. A subpopulation of circulating neutrophils expressed CBRM1/5 (CBRM1/5+) under basal conditions (6.28+/-2.59%) and was persistently expanded (9.95+/-4.0%-15.2+/-4.2%; P<0.0001) peri-operatively, whereas total CD11b expression increased only transiently, intra-operatively. L-selectin expression was unchanged on CBRM1/5+ neutrophils, and soluble L-selectin levels decreased intra-operatively (P<0.01), indicating that L-selectin was not shed. Increased CBRM1/5 expression without L-selectin loss or CD11b up-regulation was replicated in vitro by neutrophil stimulation with IL-8, C3a, and platelet-activating factor. Heparin, a known CD11b ligand, which is administered during cardiac surgery, markedly reduced neutrophil expression of conformationally active CD11b in vivo and in vitro, identifying a potential mechanism for its anti-inflammatory properties. We conclude that conformational activation of CD11b occurs on circulating neutrophils in vivo and can occur in the absence of CD11b up-regulation and L-selectin shedding.

Comparison of polymethoxyethylacrylate-coated circuits with leukocyte filtration and reduced heparinization protocol on heparin-bonded circuits in different risk cohorts

Objectives: The relative benefits of strategic leukofiltration on polymer-coated and low-dose heparin protocol on heparin-coated circuits were studied across EuroSCORE patient risk strata for three different cohorts.

Methods: In a prospective, randomized study, 270 patients undergoing coronary artery bypass grafting were allocated into three groups (n = 90): Group 1 -polymethoxyethylacrylate-coated circuits+leukocyte filters; Group 2 -polypeptide-based heparin-bonded circuits with reduced heparinization; and Group 3 -Control: uncoated circuits. Each group was further divided into three subgroups (n = 30), with respect to low- (EuroSCORE 0-2), medium- (3-5), and high- (6+) risk patients. Blood samples were collected at T1: following induction of anesthesia; T2: following heparin administration; T3: 15 min after CPB; T4: before cessation of CPB; T5: 15 min after protamine reversal; and T6: ICU.

Results: In high-risk cohorts, leukocyte counts demonstrated significant differences at T4 and T5 in Group 1, and at T4 in Group 2. Platelet counts were preserved significantly better at T4 and T5 in both groups (p <0.05 versus control). Serum IL-2 and C3a levels were significantly lower at T3, T4 and T5 in Group 1, and T4 and T5 in Group 2 (p <0.05). Postoperative bleeding, respiratory support time and incidence of atrial fibrillation were lower in the study groups versus control. Cell counts on filter mesh and heparin-coated fibers/circuits were significantly higher in the high-risk cohorts versus uncoated fibers. Phagocytic capacity increased on filter mesh, especially in high-risk specimens. SEM evaluation demonstrated better preserved coated circuits.

Conclusion: Leukofiltration and coating reduced platelet adhesion, protein adsorption, atrial fibrillation and reduced heparinization acted via modulation of systemic inflammatory response in high-risk groups.

Comparison of sample fixation and the use of LDS-751 or anti-CD45 for leukocyte identification in mouse whole blood for flow cytometry

Flow cytometry methods used to measure leukocyte function often entail sample preparation procedures that cause artifactual cell activation. To avoid leukocyte activation by isolation techniques, some preparation methods use fluorescent markers to discriminate leukocytes from erythrocytes in whole blood. One of these markers, laser dye styryl-751(LDS-751), has been used to distinguish leukocytes by staining nucleic acid, but has been found to stain other blood cells and dead cells indiscriminately. Thus, LDS-751 may not be an appropriate reagent for leukocyte identification in whole blood. Fixing samples with formaldehydes increases cell permeability and causes surface protein cross-linking that may alter staining of both intra- and extracellular markers. The degree of this sample alteration by formaldehyde fixation, however, remains in question. In addition, little is known about flow cytometry and sample preparation methods in mouse whole blood. The purpose of this study was to determine if labeling leukocytes with a monoclonal antibody specific to leukocyte common antigen (CD45) was superior to labeling with LDS-751 and to determine the effect of sample fixation on a mouse whole blood preparation for flow cytometry. Samples were incubated with CD16/CD32 Fc receptor blocker, and either 10 microg/ml LDS-751 or phosphate buffered saline (PBS). The samples were then fixed with paraformaldehyde or diluted with PBS followed by incubation with 5 microg/ml PerCP-conjugated anti-CD45, 5 microg/ml FITC-conjugated anti-CD11b, or 80 microM dichlorofluorescein diacetate. We found that samples labeled with LDS-751 demonstrated decreased fluorescence intensity for granulocyte CD11b expression and ROS production compared to samples labeled with anti-CD45. In addition, sample fixation decreased mean fluorescence intensity in samples labeled with either LDS-751 or anti-CD45. We conclude that labeling leukocytes with monoclonal antibody CD45 in a mouse whole blood preparation is preferable, as it provides improved measurement of leukocyte indices compared to LDS-751. Also, while sample fixation prior to antibody staining caused a decrease in overall fluorescence; it can be used to successfully identify extra-cellular markers.

Onset of mechanical ventilation is associated with rapid activation of circulating phagocytes in preterm infants

OBJECTIVE

In preterm infants with respiratory distress syndrome (RDS), circulating neutrophils are activated. Kinetics and effects of surfactant therapy on this activation are unknown. Therefore, we studied activation of circulating neutrophils and monocytes in newborn preterm infants with and without RDS.

PATIENTS AND METHODS

Preterm infants with RDS who were mechanically ventilated and received surfactant ("ventilated infants": n = 38; mean gestational age +/- SD: 28.3 +/- 2.2 weeks; mean birth weight +/- SD: 1086 +/- 353 g) and preterm infants who received nasal continuous positive airway pressure (n = 8) or no ventilatory support (n = 17) ("control infants": mean gestational age +/- SD: 32.1 +/- 1.2 weeks; mean birth weight +/- SD: 1787 +/- 457 g) were recruited. Blood samples were taken from ventilated infants at birth, before surfactant treatment, at 1 and 2 hours after surfactant, and at 12 to 24 hours of age. Blood samples were taken from control infants at birth, at 2 to 6 hours, and at 12 to 24 hours of age. Phagocyte CD11b expression was analyzed by flow cytometry.

RESULTS

In ventilated infants, phagocyte CD11b expression increased from birth to the first postnatal samples. It increased further by 12 to 24 hours of age. Control infants with or without nasal continuous positive airway pressure showed no significant increase after birth. At 12 to 24 hours of age, phagocyte CD11b expression was higher in ventilated infants than in control infants. In ventilated infants, neutrophil CD11b expression at 1 and 2 hours after surfactant correlated positively with gestational age.

CONCLUSIONS

In preterm infants with RDS, significant activation of circulating phagocytes occurs within 1 to 3 hours of the onset of mechanical ventilation, independent of surfactant administration, which indicates that mechanical ventilation may be the inducer of this systemic inflammatory response.

Graft protein C entrapment is associated with reduced phagocyte activation during reperfusion in human liver transplantation

OBJECTIVE

To explore the potential anti-inflammatory role of protein C pathway in ischemia-reperfusion injury during liver transplantation.

DESIGN

Prospective, observational clinical study.

SETTING

Tertiary teaching hospital.

PATIENTS

Fifty adult patients undergoing liver transplantation for acute liver failure or chronic liver disease.

INTERVENTIONS

To assess changes occurring across the transplanted liver, samples of blood entering and leaving the graft were obtained simultaneously from portal and hepatic veins. Plasma protein C and activated protein C levels, neutrophil and monocyte CD11b and L-selectin expression, and leukocyte differential counts were measured. Postoperative liver function and outcome of transplantation were recorded.

MEASUREMENTS AND MAIN RESULTS

During reperfusion, protein C became entrapped within the graft (portal vein 49% [20-96%]; graft caval effluent 25% [12-76%], p < .001), without concomitant activated protein C outflow from the graft. Simultaneously, marked neutrophil and monocyte activation occurred within the graft. Enhanced hepatic protein C entrapment was associated with reduced neutrophil and monocyte activation (R = .377, p = .011; R = .389, p = .008, respectively) during reperfusion.

CONCLUSIONS

Protein C entrapment occurs immediately during reperfusion in the graft without concomitant activated protein C release, suggesting a shortage of activated protein C in the reperfused graft. The ongoing inflammatory response during reperfusion may lead to protein C and activated protein C utilization within the graft. Indeed, hepatic protein C entrapment is associated with reduced hepatic phagocyte activation, suggesting a regulatory role for protein C pathway in hepatic reperfusion in human liver transplantation.

Activated protein C reduces graft neutrophil activation in clinical renal transplantation

We studied the role of endogenous activated protein C (APC), the major physiological anti-coagulant with concomitant anti-inflammatory properties, on ischemia/reperfusion (I/R) in 45 patients participating in a larger trial comparing three immunosuppressive protocols in cadaveric renal transplantation: perioperative anti-thymocyte globulin (ATG, Fresenius AG, Bad Homburg, Germany), perioperative basiliximab and conventional triple therapy. Blood samples for assessing plasma APC, protein C, and lactoferrin concentrations, neutrophil CD11b and L-selectin expressions and blood leukocyte differential counts were obtained preoperatively and before reperfusion from central venous cannula, complemented with simultaneous samples from iliac artery and graft vein for calculation of transrenal differences (Delta) of study parameters at 1 and 5 min after reperfusion. Unlike basiliximab or conventional therapy groups, ATG infusion induced a substantial increase in plasma APC concentration (119 [88-144]% before infusion vs. 232 [85-1246]% after infusion, p<0.001), resulting in renal graft sequestration of APC at 1 min after reperfusion (Delta=-72 [-567 to 12]%, p<0.001). Graft APC consumption was associated with transrenal reduction of neutrophil activation markers (L-selectin r=0.7, p=0.01; lactoferrin r=-0.6, p=0.02; CD11b r=-0.8, p=0.001), and with both warm (r=0.6, p=0.01) and cold ischemia time (r=0.6, p=0.02) and donor age (r=0.6, p=0.01). These findings suggest that APC has an anti-inflammatory role in I/R injury in clinical renal transplantation.

Assessment of neutrophil activation in whole blood by flow cytometry

Flow cytometry methods currently used for measuring neutrophil activation involve sample manipulation, which may result in cellular depletion and artifactual activation. To design a new methodology for measurement of neutrophil activation with minimal sample manipulation. Oxidative burst and CD 11b neutrophil expression were simultaneously assessed by a new no-lyse no-wash technique and a standard lyse-method in 10 pediatric patients with recurrent infections and two patients with chronic granulomatous disease (CGD). The new technique was based on nucleic acid staining to discriminate erythrocytes and debris without requiring physical separation. Both methods served equally to confirm or eliminate the diagnosis of CGD and leukocyte adhesion deficiency type 1. The values of baseline CD11b and oxidative burst obtained using the lysis method were significantly higher than those obtained by the no-lyse no-wash method. After activation, the lysis method resulted in higher neutrophil depletion (41%vs. 19%, P = 0.03). When compared with standard methods, neutrophil activation assessment by a no-lyse no-wash method resulted in lower neutrophil depletion and differences in oxidative burst and CD11b neutrophil values.

Activation of neutrophils and monocytes by a leukocyte-depleting filter used throughout cardiopulmonary bypass

OBJECTIVE

Cardiopulmonary bypass elicits systemic inflammation. Depletion of circulating leukocytes might alleviate inflammatory response. We studied the effects of a leukocyte-depleting filter on phagocyte activation during cardiopulmonary bypass.

METHODS

Fifty patients undergoing coronary artery bypass grafting were randomly allocated into an arterial line leukocyte filter group (n = 25) with a Pall LeukoGuard 6 leukocyte-depleting filter (LG6; Pall Biomedical, Portsmouth, United Kingdom) and a control group without any filter (n = 25). Blood sampling took place from arterial line at predetermined time points. In the filter group, the sample was taken immediately before the filter; to evaluate activation at the site, an additional sample was taken immediately after the filter. CD11b/CD18 and L-selectin expressions and basal production of hydrogen peroxide were determined with whole-blood flow cytometry, and plasma lactoferrin level was determined with enzyme-linked immunosorbent assay.

RESULTS

Neutrophil CD11b expression was higher in the filter group than in the control group (P < .001). Likewise, monocyte CD11b expression, neutrophil hydrogen peroxide production, and lactoferrin plasma levels were all significantly higher, whereas neutrophil and monocyte counts and neutrophil L-selectin expression were all significantly lower in the filter group (all P < .001). At 5 minutes of CPB, CD11b expression increased across the filter on neutrophils (median difference 197 relative fluorescence units, range 45-431 relative fluorescence units, P < .001) and monocytes (median difference 26 relative fluorescence units, range -68-111 relative fluorescence units, P < .001).

CONCLUSION

The LG6 arterial line leukocyte filter is ineffective in its principal task of diminishing phagocyte activation during cardiopulmonary bypass.

Early prediction of organ failure by combined markers in patients with acute pancreatitis

BACKGROUND

Several biological markers and clinical scoring systems have been used to predict the course of acute pancreatitis. Because organ failure is the most severe complication of the disease, prognostic markers and their combinations that would predict organ failure on hospital admission were sought.

METHODS

Some 351 consecutive patients with acute pancreatitis were studied. Blood samples were taken within 12 h of admission. This case-control study included all 33 patients with organ failure and 99 matched controls without organ failure. Measurements included 19 prognostic markers and Acute Physiology And Chronic Health Evaluation (APACHE) II score.

RESULTS

Plasma interleukin 10, serum glucose and serum calcium were identified as independent predictors of organ failure by logistic regression analysis. Calcium level correlated with clinical onset of organ failure. The combination of interleukin 10 (more than 50 pg/ml) or calcium (less than 1.65 mmol/l) was a significantly better predictor than any single marker or APACHE II score, with a sensitivity of 88 per cent, specificity 93 per cent and diagnostic odds ratio 94.

CONCLUSION

Organ failure in acute pancreatitis can be predicted with high accuracy at hospital admission using a combination of plasma interleukin 10 and serum calcium measurements.

Increased CD11b-density on circulating phagocytes as an early sign of late-onset sepsis in extremely low-birth-weight infants

Late-onset hospital-acquired sepsis is common in extremely low birth-weight (<1000 g) (ELBW) infants. The diagnosis is difficult since, at early stages of sepsis, routine laboratory tests are neither specific nor sensitive. In term infants with sepsis neutrophil surface expression of CD11b/CD18, a beta2-integrin, is significantly increased. Here we studied whether increased CD11b/CD18 density on blood neutrophils and monocytes serves as an early sepsis marker in ELBW infants. Blood samples were obtained from 30 ELBW infants on a daily basis for 3-4 postnatal weeks, and neutrophil and monocyte CD11b/CD18 expression was determined by flow-cytometry. Patients were assigned one of 3 groups: 1) an infected group, comprised of infants who had blood culture-positive sepsis and/or necrotizing enterocolitis, 2) a non-infected group, and 3) a potentially infected group, comprised of infants in whom infection was suspected but could not be confirmed microbiologically. One patient had blood culture contamination and was excluded from the analysis. In the infected group, CD11b expression gradually increased during the three days preceding sampling for blood culture. At the day of sampling, median expression of CD11b in neutrophils and monocytes was higher in the infected group than in the control group. For neutrophils the sensitivity and specificity were 1.00 and 0.56, respectively, and for monocytes, 0.86 and 0.94, respectively. From these data, we conclude that determination of CD11b/CD18 density on neutrophils and monocytes may improve diagnosis of late-onset sepsis in ELBW infants.

Association of graft neutrophil sequestration with delayed graft function in clinical renal transplantation

BACKGROUND

The authors studied the impact of neutrophil activation, detected in experimental models, on reperfusion injury in clinical renal transplantation.

METHODS

Forty-five patients from a larger trial comparing three immunosuppressive protocols were recruited: perioperative antithymocyte globulin (ATG) with low initial cyclosporine A (CsA) triple therapy (group A, n=15); two-dose basiliximab with low initial CsA triple therapy (group B, n=16); and conventional triple therapy (group C, n=14). Blood samples were obtained preoperatively, before reperfusion, and at 1 and 5 min after reperfusion. During reperfusion, samples were collected from the iliac artery and the graft vein for calculation of transrenal differences (Delta) of study parameters. Leukocyte differential counts, plasma lactoferrin concentration, and neutrophil CD11b and L-selectin expressions were assessed. Graft blood flow was measured at 2 and 30 min after reperfusion.

RESULTS

ATG induced neutrophil activation already before reperfusion. Thus, group A was excluded, but groups B and C were pooled for analysis of reperfusion-induced neutrophil activation. At 1 min after reperfusion, lactoferrin concentration was higher in graft vein than iliac artery, yielding Delta=15 microg/L (P<0.05). Concomitantly, Delta neutrophil count correlated with both Delta L-selectin expression (R=0.49, P=0.012) and graft blood flow at 2 min (R=0.51, P=0.007). At 5 min after reperfusion, 0.17 (-1.0-0.24)x10 cells/L neutrophils were sequestered in the graft (P<0.001). This sequestration correlated with graft blood flow at 30 min (R=0.53, P=0.005) and was stronger in patients with delayed graft function (DGF) (Delta = -0.38 [-1.45 to -0.2]) than those without (Delta = -0.12 [-0.41-0.24], P<0.001). In multiple regression analysis, sequestration was the most important parameter associated with DGF.

CONCLUSIONS

Neutrophils are activated and sequestered in the reperfused graft during clinical renal transplantation. Neutrophil sequestration is a powerful independent factor explaining the incidence of DGF.

A standardized procedure for quantitation of CD11b on polymorphonuclear neutrophil by flow cytometry: potential application in infectious diseases

An up-regulation of the surface marker CD11b has been demonstrated during polymorphonuclear (PMN) cell activation. CD11b over-expression is often associated with inflammation and is considered as an early marker of infection. However, the absence of standardized assay and the variability of preanalytical settings leading to PMN artifactual activation have compromised the interest of this marker. In the present study a standardized quantitative flow cytometry assay directly performed in whole blood has been used to determine CD11b expression on PMN cells. The results indicate that quantitative flow cytometry can provide consistent CD11b density values between laboratories provided that a calibration system is used including specific calibrators, reagents and protocols. This method allowed us to evidence an up-regulation of CD11b expression for infected patients. This quantitation is a standardized and potentially useful method in clinical situations implying quantitative CD11b expression variations.

Activation of protein C during reperfusion in clinical liver transplantation

BACKGROUND

Activated protein C (APC) exhibits anticoagulant and antiinflammatory properties. We studied the kinetics and magnitude of protein C activation in clinical liver transplantation and the interaction of this activation with neutrophil and monocyte activation.

METHODS

In 10 patients undergoing liver transplantation, we measured plasma protein C and APC levels, neutrophil and monocyte CD11b and L-selectin expression, and leukocyte differential counts pre-, intra-, and postoperatively. Samples of blood entering and leaving the liver were obtained simultaneously to assess changes across the liver.

RESULTS

Protein C level was low preoperatively (65%, range 39%-141%) and remained low throughout surgery. Compared with the preoperative level (107%, range 78%-161%), APC level increased during liver reperfusion (471%, range 183%-917%, P=0.05). A transhepatic decrease in protein C level (-16%, range -45%-5%, P=0.007), but not in APC level, occurred during initial liver reperfusion. At the same time, neutrophil and monocyte activation took place in the liver.

CONCLUSIONS

Despite protein C deficiency, patients with liver insufficiency are able to maintain normal APC levels. During reperfusion, protein C consumption occurs in the liver without concomitant hepatic release of APC, indicating a shortage of APC in the reperfused liver. The process consuming protein C and APC may be related to the simultaneous ongoing neutrophil and monocyte activation within the liver graft, indicating a regulatory role for APC in inflammation.

Ethylenediaminetetraacetic acid plus citrate-theophylline-adenosine-dipyridamole (EDTA-CTAD): a novel anticoagulant for the flow cytometric assessment of platelet and neutrophil activation ex vivo in whole blood

Ethylenediaminetetraacetic acid (EDTA) is the anticoagulant recommended for full blood counts, citrate is recommended for coagulation and platelet studies, and citrate-theophylline-adenosine-dipyridamole (CTAD) inhibits platelet activation. Because the combination of EDTA and CTAD (E/C) is better than EDTA or CTAD alone for measuring platelet parameters on the ADVIA 120 Haematology System, we investigated whether it also offers advantages for the flow cytometric assessment of platelet and/or neutrophil activation and platelet-leucocyte aggregate formation ex vivo. Blood from healthy subjects was collected into E/C or citrate, kept at room temperature or at 4 degrees C, and analysed 0 to 360 min later in the ADVIA 120 and by immunofluorescent flow cytometry. Platelet count, mean platelet volume, number of platelet clumps, mean platelet component, numbers of CD62P(+) platelets and platelet-leucocyte aggregates, and expression of CD11b on neutrophils changed little over 360 min in blood with E/C kept at 4 degrees C. In contrast, one or more parameter changed when blood was kept with E/C at ambient temperature or with citrate at either temperature. The use of E/C in in vitro and in vivo studies is illustrated. Platelet and neutrophil activation status ex vivo can be reliably assessed if blood is collected into E/C, held at 4 degrees C, and analysed within 6 h.

Immunofluorescent surface labelling, flow sorting and culturing of putative epidermal stem cells derived from small skin punch biopsies

Basal keratinocytes of human epidermis strongly express the cell surface glycoprotein beta(1)-integrin, and putatively harbour epidermal stem cells. Selective sorting and culturing of keratinocyte stem cells forms the basis for studies on the role of these cells as targets for therapeutic intervention and gene therapy. Here we have studied variables which affect cell surface labelling for beta(1)-integrin, flow sorting and subsequent culturing of beta(1)-integrin-positive and beta(1)-integrin-negative keratinocytes. Keratinocytes were derived from small human skin punch biopsies (3 or 4 mm in diameter), and we tested a number of variables such as choice of proteolytic enzyme for cell isolation, cell concentration, fixation, storage of fixed cell suspensions and labelling conditions. In contrast to thermolysin treatment for cell isolation, trypsin treatment left most cell surface beta(1)-integrin molecules intact. Ethanol and paraformaldehyde fixation interfered with beta(1)-integrin detection, and unfixed cells gave the best results. Optimisation of all the individual steps resulted in a labelling protocol for reproducible staining and sorting of the cells. Sorted cells were seeded in 96-well plates (300 cells/well) and colonies were obtained in more than 50% of the wells with beta(1)-integrin-positive keratinocytes. In plates with beta(1)-integrin-negative cells, only 10% of the wells contained keratinocyte colonies. Flow sorted keratinocytes obtained by trypsin formed numerous colonies in cell culture experiments. In cell suspensions obtained with thermolysin, only sparse colonies were formed. We conclude that our methodology permits the use of small human tissue samples for cell labelling and sorting, while preserving the clonogenic potential.

Neutrophil activation in preterm infants who have respiratory distress syndrome

OBJECTIVE

To study neutrophil activation in circulation as a sign of systemic inflammation in preterm infants with respiratory distress syndrome.

METHODS

The study comprised very low birth weight preterm infants who had respiratory distress syndrome and required intubation and mechanical ventilation (n = 51), 1-day-old preterm infants who had no need for mechanical ventilation (n = 12), term infants (n = 47), and adult volunteers (n = 25). Neutrophil surface expression of CD11b was quantified with flow cytometry.

RESULTS

In preterm infants with respiratory distress syndrome, neutrophil CD11b expression during the first day of life was higher than in cord blood (mean: 165 relative fluorescence units [RFU] [standard deviation [SD]: 53], n = 29 vs 83 RFU [SD: 21], n = 11; 95% confidence interval [CI] for difference: 59-106) or in preterm infants without mechanical ventilation (106 RFU [SD: 33], n = 12; 95% CI for difference: 17-90). CD11b expression decreased by age of 10 days. CD11b expression was lower in preterm cord than in term cord blood (95% CI for difference: 5-53). However, in preterm infants with respiratory distress syndrome aged 2 to 5 days, it was higher than in term infants of that age.

CONCLUSIONS

The observations demonstrate an early transient postnatal neutrophil activation indicative of systemic inflammation that may contribute to the tissue injury in preterm infants with respiratory distress syndrome.

Extracellular release of bactericidal/permeability-increasing protein in newborn infants

Upon activation, polymorphonuclear leucocytes (PMN) release bactericidal/permeability-increasing protein, (BPI) from their azurophil granules. BPI selectively binds to the lipopolysaccharide (LPS) on gram-negative bacteria and induces their death. This study examined plasma BPI concentration levels in healthy newborns and in newborns with clinical sepsis, and the ability of PMN from preterm and term infants to release BPI. We also studied the release of myeloperoxidase (MPO), and the surface expression of adhesion molecule CD11b on PMN. In infants with clinical sepsis, plasma BPI concentration was higher, 27.8 microg/L [8.6-883; median (range)] (n = 11), than in healthy term infants 8.9 microg/L (3.9-179) (n = 17), and in adults 7.3 microg/L (0.7 -18.4) (n = 15); p = 0.014, Kruskal-Wallis. In preterm infants (n = 8), the ability of PMN to release BPI in vitro after stimulation with PMA was 8.8, in term infants it was 15.9 (n = 29; p > 0.05 vs. preterm infants) and in adults 23.4 ng/10(6) PMN (n = 15; p = 0.024 and p > 0.05 vs. preterm and term infants, respectively). The corresponding values of MPO were 20.0 ng/10(6) (11.3-46.7) in preterms, 19.0 ng/10(6) (2.2-223.7) in terms, and 27.8 ng/10(6) (9.1-80.7) in adults; p = 0.67 between groups. In infants with clinical sepsis, CD11b level was higher, 292 RFU (234-403) than the basal CD11b expression levels in healthy newborn infants, 116 RFU (76-145); P = 0.0001. FMLP-stimulated PMN CD11b expressions in preterm cord blood, 1071 RFU (552-1286) and in term cord blood, 918 (567-1472) were on the same level, but lower than that in adult blood, 1592 (973-1946); p < 0.001, ANOVA. Our findings suggest that in preterm infants the ability to release BPI is lower than in adults and term infants. These findings suggest that premature neonates have an impaired ability to mobilize BPI, possibly contributing to their marked susceptibility to infections with Gram-negative bacteria.

A prospective study of inflammation markers in patients at risk of indirect acute lung injury

Systemic inflammation triggered by insults like sepsis and acute pancreatitis may play a role in development of indirect acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). Because little is known about the course of systemic inflammation on the days preceding diagnosis of ARDS, we prospectively monitored immune inflammatory status in 52 patients at risk and we assessed the presence of ALI and ARDS on day 7 after admission to the intensive care unit. On admission, serum interleukin (IL) 8, IL-6, and soluble IL-2 receptor concentrations were significantly higher in patients with subsequent ALI (n = 18) than in patients without ALI (n = 30). During a 4-day follow-up, IL-8 and IL-6 levels of ALI patients remained high and those of non-ALI patients decreased. None of the markers discriminated ARDS patients (n = 9) from non-ARDS ALI patients (n = 9). Among 11 patients with acute pancreatitis, ALI patients had significantly higher IL-8, IL-6, and phagocyte CD11b expression levels than did non-ALI patients, whereas among 14 patients with massive transfusion, respective findings in ALI and non-ALI patients were comparable. Results give credence to the view that systemic inflammation plays a role in development of ALI triggered by pancreatitis, but not in that by massive transfusion. This finding, if confirmed in studies with sufficient statistical power, suggests that the patients with massive transfusion do not necessarily benefit from novel biotherapies aimed at altering the course of systemic inflammation.

Systemic inflammation and innate immune response in patients with previous anterior uveitis

AIM

To determine the presence of systemic inflammation and innate immune responsiveness of patients with a history of acute anterior uveitis but no signs of ocular inflammation at the time of recruitment.

METHODS

Tumour necrosis factor alpha (TNF-alpha) production in response to bacterial lipopolysaccharide (LPS) was studied using whole blood culture assay; levels of TNF-alpha in culture supernatants, and soluble interleukin 2 receptor (sIL-2R) in serum were determined by chemiluminescent immunoassay (Immulite); monocyte surface expression of CD11b, CD14, and CD16 and the proportion of monocyte subsets CD14(bright)CD16(-) and CD14(dim)CD16(+) were studied with three colour whole blood flow cytometry; and serum C reactive protein (CRP) levels were determined using immunonephelometric high sensitivity CRP assay.

RESULTS

The CRP level (median, interquartile range) was significantly higher in 56 patients with previous uveitis than in 37 controls (1.59 (0.63 to 3.47) microg/ml v 0.81 (0.32 to 2.09) microg/ml; p=0.008). The TNF-alpha concentration of the culture media per 10(5) monocytes was significantly higher in the patient group than in the control group in the presence of LPS 10 ng/ml (1473 (1193 to 2024) pg/ml v 1320 (935 to 1555) pg/ml; p=0.012) and LPS 1000 ng/ml (3280 (2709 to 4418) pg/ml v 2910 (2313 to 3358) pg/ml; p=0.011). The background TNF-alpha release into the culture media was low in both groups. CD14 expression of CD14(bright)CD16(-) monocytes, defined as antibody binding capacity (ABC), was similar for the patients and controls (22,839 (21,038 to 26,020) ABC v 21,657 (19,854 to 25,646) ABC).

CONCLUSIONS

Patients with previous acute anterior uveitis show high innate immune responsiveness that may play a part in the development of ocular inflammation.

The role of CD47 in neutrophil transmigration. Increased rate of migration correlates with increased cell surface expression of CD47

CD47, a cell surface glycoprotein, plays an important role in modulating neutrophil (PMN) migration across endothelial and epithelial monolayers. Here we show that anti-CD47 monoclonal antibodies (mAbs) delay PMN migration across collagen-coated filters or T84 epithelial monolayers toward the chemoattractant formylmethionylleucylphenylalanine (fMLP). Despite delayed transmigration by anti-CD47 mAbs, the numbers of PMN migrating across in either condition were the same as in the presence of control non-inhibitory mAbs. Cell surface labeling and immunoprecipitation demonstrated upregulation of CD47 to the PMN cell surface with kinetics similar to those of the transmigration response. Subcellular fractionation studies revealed redistribution of CD47 from intracellular compartments that co-sediment with secondary granules to plasma membrane-containing fractions after fMLP stimulation. Experiments performed to investigate potential signaling pathways revealed that inhibition of tyrosine phosphorylation with genistein reversed the anti-CD47-mediated PMN migration delay, whereas inhibition of phosphatidylinositol 3-kinase only partially reversed anti-CD47 effects that correlated with a rapid increase in PMN cell surface CD47. Analysis of the contribution of epithelial-expressed CD47 to PMN transmigration revealed that PMN migration across CD47-deficient epithelial monolayers (CaCO2) was significantly increased after stable transfection with CD47. These results suggest that cell surface CD47 and downstream tyrosine phosphorylation signaling events regulate, in part, the rate of PMN migration during the inflammatory response.

Neutrophil CD11b expression and circulating interleukin-8 as diagnostic markers for early-onset neonatal sepsis

OBJECTIVE

To assess neutrophil CD11b and circulating interleukin 8 (IL-8) as markers of early-onset infection in neonates.

METHODS

The study comprised 39 neonates, with a gestational age of 29 to 41 weeks, suspected of infection within 48 hours of life. Neutrophil surface expression of CD11b was quantified with flow cytometry and plasma IL-8 with an enzyme-linked immunosorbent assay. Both data were available from 35 of 39 neonates. Serum C-reactive protein was determined at initial evaluation and, later, on the basis of the clinical picture. Neonates were allocated retrospectively into 2 groups. In the sepsis group (N = 22), 4 had culture-proven sepsis, and 14 had an antenatal risk factor for infection. In the possible-infection group (N = 13), each neonate had a noninfective disorder, but co-occurring infection remained a possibility. Twelve healthy term infants served as controls.

RESULTS

CD11b expression and IL-8 levels both increased in order of sepsis > possible infection > healthy. Sensitivity and specificity by the CD11b test for sepsis were equal, at 1.00, and those by the IL-8 test 0.91 and 1.00, respectively; 6 (17.1%) of the 35 neonates had CD11b and IL-8 below cutoff levels.

CONCLUSIONS

Measuring neutrophil CD11b expression and circulating IL-8 provides a means to identify early-onset neonatal sepsis. The findings may be helpful in planning strategies to safely reduce the use of antimicrobials in neonates.

Human granulocyte CD11b expression as a pharmacodynamic biomarker of inflammation

A method has been developed for the direct quantification of the CD11b integrin on granulocytes by flow cytometric analysis of whole blood specimens following either LTB(4) or lipopolysaccharide (LPS) stimulation. This method has utility in evaluating the pharmacodynamic action of either LTB(4) receptor antagonists or immune cell modulators in effecting CD11b integrin expression and granulocyte activation in human subjects administered such drugs. Previous studies using CD11b as a biomarker of granulocyte activation have faltered because of the difficulty in controlling the activation state of the granulocyte following removal of blood from subjects. The present study has made use of a newly validated method using either LTB(4) or LPS to stimulate CD11b expression on granulocytes and has been used, as one measure, in the evaluation of LPS activity when administered to normal human volunteers.

Transhepatic neutrophil and monocyte activation during clinical liver transplantation

BACKGROUND

During experimental liver transplantation, neutrophil sequestration results in increased oxygen free radical production and correlates inversely with graft viability. Neutrophil activation in clinical liver transplantation is poorly understood.

METHODS

We assessed leukocyte sequestration and transhepatic differences of neutrophil and monocyte CD11b expression, neutrophil free radical production, and plasma concentrations of interleukin 6 and interleukin 8 in nine patients during liver transplantation.

RESULTS

Significant hepatic neutrophil sequestration occurred during initial graft rewarming with portal blood, after inferior vena cava declamping, and after hepatic artery declamping (all P<0.05). A positive transhepatic difference (i.e., outcoming - ingoing) in CD11b expression of neutrophils was observed after portal vein declamping (51+/-32 relative fluorescence unit [RFU]) and in CD11b expression of monocytes during initial graft rewarming (67+/-86 RFU, both P<0.05). A transcoronary increase in both unstimulated (74+/-80 RFU) and N-formyl-methionyl-leucylphenylalanine-stimulated (112+/-168 RFU) neutrophil free radical production took place after hepatic artery declamping (both P<0.05). A negative transcoronary difference of interleukin 6 occurred during initial graft rewarming (-192+/-176 pg/ml) and a positive difference of interleukin 8 occurred after hepatic artery declamping (17+/-23 pg/ml, both P<0.05).

CONCLUSIONS

Hepatic sequestration and transhepatic activation of neutrophils, and hepatic production of interleukin 8 occur during clinical liver transplantation. A splanchnic influx of interleukin 6 occurs to the graft, possibly modulating neutrophil-mediated graft reperfusion injury.

Down-regulated RPS3a/nbl expression during retinoid-induced differentiation of HL-60 cells: a close association with diminished susceptibility to actinomycin D-stimulated apoptosis

The efficacy of anticancer agents significantly depends on the differential susceptibility of undifferentiated cancer cells and differentiated normal cells to undergo apoptosis. We previously found that enhanced expression of RPS3a/nbl, which apparently encodes a ribosomal protein, seems to prime cells for apoptosis, while suppressing such enhanced expression triggers cell death. The present study found that HL-60 cells induced to differentiate by all-trans retinoic acid did not undergo apoptosis following treatment with actinomycin D whereas undifferentiated HL-60 cells were highly apoptosis-susceptible, confirming earlier suggestions that differentiated cells have diminished apoptosis-susceptibility. Undifferentiated HL-60 cells highly expressed RPS3a/nbl whereas all-trans retinoic acid -induced differentiated cells exhibited markedly reduced levels, suggesting that apoptosis-resistance of differentiated cells could be due to low RPS3a/nbl expression. Down-regulation of enhanced RPS3a/nbl expression was also observed in cells induced to differentiate with the retinoid 4-[(E)-2-(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-napthalenyl)-1- propenyl]benzoic acid without any significant induction of cell death. While down-regulation of RPS3a/nbl expression during differentiation did not apparently induce apoptosis, RPS3a/nbl antisense oligomers triggered death of undifferentiated HL-60 cells, but not of retinoid-induced differentiated cells. It therefore seems that while down-regulation of enhanced RPS3a/nbl expression can induce apoptosis in undifferentiated cells, down-regulation of enhanced RPS3a/nbl expression during differentiation occurs independently of apoptosis, and could be regarded as reverting the primed condition to the unprimed (low RPS3a/nbl) state.

The use of flow cytometry to measure neutrophil function

Neutrophils are important professional phagocytic cells that provide the host with a first line of defense against acute bacterial and fungal diseases and recurrent, severe or unusual infections are associated with inherited defects of neutrophil function. Furthermore, abundant evidence links inappropriate neutrophil-mediated tissue damage to the pathogenesis of conditions such as acute respiratory distress syndrome, septicemia with multiorgan failure, ischemia-reperfusion injury and rheumatoid arthritis. Flow cytometry has been increasingly used to evaluate the functional capabilities of neutrophils. In this review, we discuss the use of flow cytometry to assess neutrophil functional responses including calcium mobilization, F-actin assembly, adhesion, aggregation, degranulation, phagocytosis and reactive oxygen species (ROS) production. The use of flow cytometry to identify neutrophil priming is also discussed. The advantage of flow cytometry is that the majority of neutrophil functions can be measured using a small volume of whole blood that reduces artifactual changes in function caused by purification procedures. The advent of numerous new fluorochromes and multiparametric analysis allows the simultaneous measurement of several neutrophil functions in the same population of cells. Flow cytometric analysis provides a rapid screen for abnormalities of neutrophil function and reflects more accurately their behavior in vivo.

Mechanisms and consequences of phagocyte adhesion to endothelium

Leukocyte adhesion to endothelium is essential for the development of an appropriate immune-inflammatory response. The vital importance of leukocyte-endothelial adhesive interactions in host defense and homeostasis is illustrated by the clinical manifestations of patients with congenital defects of leukocyte adhesion functions. However, under some circumstances leukocyte adhesion to endothelium may instead lead to vascular and tissue damage. In recent years, there has been remarkable progress in the understanding of the molecular basis of leukocyte adhesion to endothelium, and this knowledge has led to a new approach to immunomodulation in human disease, ie 'antiadhesion' therapy. This review focuses on cell adhesion molecules mediating adhesion of circulating phagocytes to vascular endothelium, on congenital defects of phagocyte adhesion in man, and on the current status of antiadhesion therapy directed towards phagocyte and endothelial adhesion molecules. We will also consider markers of phagocyte activation, which may provide a means to identify those patients who would benefit most from antiadhesion therapy.

A potential role of an intracellular signaling defect in neutrophil functional abnormalities and promotion of tissue damage in patients with localized juvenile periodontitis

Localized juvenile periodontitis is a destructive form of periodontal inflammatory disease which has its onset at puberty. The etiopathology of the disease is still unclear but neutrophils have been suggested to play a major role both in the production and development of the disorder. About 70% of the patients with localized juvenile periodontitis exhibit neutrophil functional abnormalities, such as decreased chemotaxis and phagocytosis. Interestingly, it has been frequently reported that the same hypoactive cells show an enhanced respiratory burst response and increased adhesion. Several possible mechanisms explaining neutrophil anomalies in localized juvenile periodontitis have been proposed. These include the presence of soluble serum factors capable of modulating neutrophil function, altered cell-surface receptor expression and/or function, and a change in the post-receptor signaling events. Recently, a growing evidence has accumulated showing that the diacylglycerol metabolism could be altered in neutrophils from patients with localized juvenile periodontitis. This change, which may be due to a defect in a major diacylglycerol metabolizing enzyme, diacylglycerol kinase, results in enhanced accumulation of diacylglycerol in activated cells. Because diacylglycerol is an endogenous activator of protein kinase C, the increased and prolonged generation of diacylglycerol could lead to abnormal pattern of protein kinase C-regulated neutrophil functions, explaining the parallel hypo- and hyperactivities.

Anti-ICAM-1 Monoclonal Antibody R6.5 (Enlimomab) Promotes Activation of Neutrophils in Whole Blood

R6.5 (BIRR-1, Enlimomab), a murine IgG2a mAb to the human ICAM-1, inhibits leukocyte adhesion to the vascular endothelium, thereby decreasing leukocyte extravasation and inflammatory tissue injury. In initial clinical trials, R6.5 proved to be beneficial in reducing both disease activity in refractory rheumatoid arthritis and the incidence of acute rejection after kidney and liver allograft transplantations. However, adverse effects such as fever, leukopenia, or cutaneous reactions were not infrequent. We studied the effects of R6.5 on neutrophil function in whole blood samples ex vivo. Surprisingly, at the concentrations achieved in clinical trials, R6.5 activated neutrophilic granulocytes, as indicated by a significant increase in expression of the adhesion molecule β2-integrin CD11b, a concurrent decrease in L-selectin expression, and an enhancement of the oxidative burst activity. Neutrophil activation was not exerted by an anti-ICAM-1 mAb of the IgG1 isotype, by isotype-matched, irrelevant anti-2-phenyloxazolone mAb, or by F(ab′)2 fragments of R6.5. Neutrophil activation was completely inhibited by soluble complement receptor type 1. We conclude that in whole blood, R6.5 activates resting neutrophils in a complement-dependent manner. This finding can explain, at least in part, the side effects associated with R6.5 therapy.