Relationship between domestic smoking and metals and rare earth elements concentration in indoor PM2.5.

Cigarette smoke is the main source of indoor chemical and toxic elements. Cadmium (Cd), Thallium (Tl), Lead (Pb) and Antimony (Sb) are important contributors to smoke-related health risks. Data on the association between Rare Earth Elements (REE) Cerium (Ce) and Lanthanum (La) and domestic smoking are scanty. To evaluate the relationship between cigarette smoke, indoor levels of PM2.5 and heavy metals, 73 children were investigated by parental questionnaire and skin prick tests. The houses of residence of 41 "cases" and 32 "controls" (children with and without respiratory symptoms, respectively) were evaluated by 48-h PM2.5 indoor/outdoor monitoring. PM2.5 mass concentration was determined by gravimetry; the extracted and mineralized fractions of elements (As, Cd, Ce, La, Mn, Pb, Sb, Sr, Tl) were evaluated by ICP-MS. PM2.5 and Ce, La, Cd, and Tl indoor concentrations were higher in smoker dwellings. When corrected for confounding factors, PM2.5, Ce, La, Cd, and Tl were associated with more likely presence of respiratory symptoms in adolescents. We found that: i) indoor smoking is associated with increased levels of PM2.5, Ce, La, Cd, and Tl and ii) the latter with increased presence of respiratory symptoms in children.

Ci8 short, a novel LPS-induced peptide from the ascidian Ciona intestinalis, modulates responses of the human immune system.

The selective modulation of immunity is an emerging concept driven by the vast advances in our understanding of this crucial host defense system. Invertebrates have raised researchers' interest as potential sources of new bioactive molecules owing to their antibacterial, anticancer and immunomodulatory activities. A LipoPolySaccharide (LPS) challenge in the ascidian Ciona intestinalis generates the transcript, Ci8 short, with cis-regulatory elements in the 3' UTR region that are essential for shaping innate immune responses. The derived amino acidic sequence in silico analysis showed specific binding to human Major Histocompatibility Complex (MHC) Class I and Class II alleles. The role of Ci8 short peptide was investigated in a more evolved immune system using human Peripheral Blood Mononuclear Cells (PBMCs) as in vitro model. The biological activities of this molecule include the activation of 70kDa TCR ζ chain Associated Protein kinase (ZAP-70) and T Cell Receptor (TCR) Vß oligo clonal selection on CD4+ T lymphocytes as well as increased proliferation and IFN-γ secretion. Furthermore Ci8 short affects CD4+/CD25high induced regulatory T cells (iTreg) subset selection which co-expressed the functional markers TGF-ß1/Latency Associated Protein (LAP) and CD39/CD73. This paper describes a new molecule that modulates important responses of the human adaptive immune system.

Hydroxytyrosol modulates Par j 1-induced IL-10 production by PBMCs in healthy subjects.

Several papers have demonstrated the importance of substances from natural sources which can exert powerful anti-inflammatory effects. In this respect, hydroxytyrosol, one of the major elements of the phenolic components of olive oil, has been extensively studied for its anti-inflammatory activities and safety profile. In this report, we demonstrate that the co-stimulation of human PBMCs from healthy subjects with the Par j 1 allergen and hydroxytyrosol induced a statistically significant increase in the amount of Par j 1-induced IL-10, demonstrating that hydroxytyrosol can modulate an allergen-specific immune response potentiating a suppressive immune response towards an allergen. Our work opens the way to further studies to elaborate the possibility of using hydroxytyrosol as a nutrient for allergy prevention.

An elevated body mass index increases lung volume but reduces airflow in Italian schoolchildren.

BACKGROUND: Asthma and obesity are important and growing health issues worldwide. Obesity is considered a risk factor for asthma, due to the induction of changes in airway mechanics and altered airway inflammation. METHODS: We cross-sectionally investigated the effect of increased weight on pulmonary function in a large population sample of healthy children, aged 10-17 yrs living in Palermo, Italy. Explanatory effect of weight on lung function variables were evaluated by multiple linear regression models, taking into account height, gender, and age-class. RESULTS: Among the 2,393 subjects, FVC and FEV1 were positively correlated to weight. Multiple regression models showed that the weight beta coefficient for FEV1 was significantly lower with respect to that for FVC (0.005 and 0.009 l/kg, respectively), indicating a different magnitude in explanatory effect of weight on FVC and FEV1. Both FEV1/FVC and FEF25-75%/FVC ratios were negatively correlated to weight, while FEF25-75% was not significantly correlated. Similar results were obtained also when 807 symptomatic subjects were introduced in the model through a sensitivity analysis. CONCLUSION: In healthy children, the disproportionate increase of FEV1 and FVC with weight produces airflow decrease and consequently apparent poorer lung function independently from respiratory disease status.

Effect of indoor nitrogen dioxide on lung function in urban environment.

BACKGROUND: High levels of indoor NO2 are associated with increased asthma symptoms and decreased expiratory peak flows in children. We investigated the association of exposure to domestic indoor NO2, objectively measured in winter and spring, with respiratory symptoms and lung function in a sample of adolescents from a southern Mediterranean area. METHODS: From a large school population sample (n=2150) participating in an epidemiological survey in the urban area of the City of Palermo (southern Italy), a sub-sample of 303 adolescents was selected which furnished an enriched sample for cases of current asthma. All subjects were evaluated by a health questionnaire, skin prick tests and spirometry. One-week indoor NO2 monitoring of their homes was performed by diffusive sampling during spring and again during winter. RESULTS: We found that about 25% of subjects were exposed to indoor NO2 levels higher than the 40µg/m(3) World Health Organization limit, during both spring and winter. Moreover, subjects exposed to the highest indoor NO2 concentrations had increased frequency of current asthma (p=0.005), wheeze episodes in the last 12 months (p<0.001), chronic phlegm (p=0.013), and rhinoconjunctivitis (p=0.008). Finally, subjects with a personal history of wheeze ever had poorer respiratory function (FEF25-75%, p=0.01) when exposed to higher indoor NO2 concentrations. CONCLUSIONS: Home exposure to high indoor NO2 levels frequently occurs in adolescents living in a southern Mediterranean urban area and is significantly associated with the risks for increased frequency of both respiratory symptoms and reduced lung function.

The burden of rhinitis and rhinoconjunctivitis in adolescents.

PURPOSE: Rhinitis and conjunctivitis are common diseases worldwide that are frequently associated. Nevertheless, the risk factors for rhinoconjunctivitis are not well-described and the impact of conjunctivitis on rhinitis and asthma in children remains unknown. This study explored the different risk factors and evaluated the burden of rhinoconjunctivitis among adolescents. METHODS: This was a cross-sectional study conducted on a random sample of schoolchildren, aged 10-17 years, using skin prick tests and a self-administered questionnaire on respiratory health investigating the impact of rhinitis and rhinoconjunctivitis on daily activities. RESULTS: A complete evaluation was obtained for 2,150 children. The prevalence of rhinitis alone was 18.2% and rhinitis associated with conjunctivitis was 20.5%. Rhinoconjunctivitis was more frequently associated with females, a parental history of atopy, domestic exposure to mold/dampness, passive smoke exposure, and reported truck traffic in residential streets. Moreover, rhinoconjunctivitis was associated with a higher level of allergic sensitization. The prevalence of current asthma was 1.7% in subjects without rhinitis or rhinoconjunctivitis, 5.1% in rhinitis and 10.7% in rhinoconjunctivitis. In a logistic model, rhinoconjunctivitis yielded a 2-fold risk for current asthma with respect to rhinitis. Subjects with rhinoconjunctivitis had poorer quality of life (QoL); there was an impact on daily activities in 4.6% of rhinitis and 10.7% of rhinoconjunctivitis. CONCLUSIONS: Ocular symptoms increase the role of rhinitis as a risk factor for asthma and its impact on daily activities in children.

Rhinitis as a risk factor for depressive mood in pre-adolescents: a new approach to this relationship.

BACKGROUND: Respiratory allergic symptoms impact on social life and school activities, influencing the patient's mood states. We evaluated the relationships between allergic respiratory diseases and depressive/anxious mood in a large sample of Italian middle school students, using the partial directed acyclic graph (P-DAG). METHODS: We studied 1283 subjects aged 10-13. A health respiratory questionnaire including questions relevant to socioeconomic status (HCI) and a test for depression and anxiety were administered. All subjects performed spirometry and skin prick tests. RESULTS: A causal role of rhinitis on depression was found: the likelihood of being depressed increased from 11.2 to 17.7%, when rhinitis was present. Moreover, a direct effect of low HCI on depressive mood was shown (p < 0.0001) as well as the correlation between anxiety and depression (p < 0.0001). Gender was not a direct causal factor for depressive mood, but their relation was mediated through anxious mood. Anxiety appeared to have a stronger association with depression than gender. Allergic sensitization was significantly related to both asthma and rhinitis (p < 0.0001, respectively). Asthma and rhinitis were also directly associated (p < 0.0001). Conversely, asthma was not directly associated with depressive mood, but their relation was mediated through rhinitis. Body mass index (BMI) and impaired lung function (IPF) were not associated with the other variables. CONCLUSIONS: The use of this novel approach to analyzing the dynamic relationships allowed us to find a causal role of rhinitis on depressive state. Moreover, anxious condition and low socioeconomic status contributed to induce depressive mood.

An allergen-polymeric nanoaggregate as a new tool for allergy vaccination.

A recombinant hybrid composed of the two major allergens of the Parietaria pollen Par j 1 and Par j 2 has been generated by DNA recombinant technology (PjED). This hybrid was produced in E. coli at high levels of purity. Then, the engineered derivative has been combined with a synthetic polyaminoacidic derivative having a poly(hydroxyethyl)aspartamide (PHEA) backbone and bearing both butyryl groups (C4) and succinyl (S) moieties in the side chain (PHEA-C4-S). The allergen-copolymer nanoaggregate was characterized by means of DLS, zeta potential, electrophoretic mobility and atom force microscopy analysis displaying the formation of a stable complex. Its safety has been proved in vitro on a murine cell line, human erythrocytes and basophils. Moreover, the formation of the complex did not alter the ability of the allergens to cross-link surface bound specific IgE demonstrating that the combination of an engineered hybrid with a copolymer did not interfere with its biological activity suggesting its employment as potential vaccine against Parietaria-induced allergies.

Gemcitabine sensitizes lung cancer cells to Fas/FasL system-mediated killing.

Gemcitabine is a chemotherapy agent commonly used in the treatment of non-small cell lung cancer (NSCLC) that has been demonstrated to induce apoptosis in NSCLC cells by increasing functionally active Fas expression. The aim of this study was to evaluate the Fas/Fas ligand (FasL) system involvement in gemcitabine-induced lung cancer cell killing. NSCLC H292 cells were cultured in the presence or absence of gemcitabine. FasL mRNA and protein were evaluated by real-time PCR, and by Western blot and flow cytometry, respectively. Apoptosis of FasL-expressing cells was evaluated by flow cytometry, and caspase-8 and caspase-3 activation by Western blot and a colorimetric assay. Cytotoxicity of lymphokine-activated killer (LAK) cells and malignant pleural fluid lymphocytes against H292 cells was analysed in the presence or absence of the neutralizing anti-Fas ZB4 antibody, by flow cytometry. Gemcitabine increased FasL mRNA and total protein expression, the percentage of H292 cells bearing membrane-bound FasL (mFasL) and of mFasL-positive apoptotic H292 cells, as well as caspase-8 and caspase-3 cleavage. Moreover, gemcitabine increased CH11-induced caspase-8 and caspase-3 cleavage and proteolytic activity. Cytotoxicity of LAK cells and pleural fluid lymphocytes was increased against gemcitabine-treated H292 cells and was partially inhibited by ZB4 antibody. These results demonstrate that gemcitabine: (i) induces up-regulation of FasL in lung cancer cells triggering cell apoptosis via an autocrine/paracrine loop; (ii) induces a Fas-dependent apoptosis mediated by caspase-8 and caspase-3 activation; (iii) enhances the sensitivity of lung cancer cells to cytotoxic activity of LAK cells and malignant pleural fluid lymphocytes, partially via Fas/FasL pathway. Our data strongly suggest an active involvement of the Fas/FasL system in gemcitabine-induced lung cancer cell killing.

Lymphocyte apoptosis in children with central nervous system tuberculosis: a case control study.

BACKGROUND: Studies of the apoptosis mechanisms involved in the pathogenesis of tuberculosis have suggested that Mycobacterium tuberculosis can actively interfere with the apoptosis of infected cells. In vivo studies have been performed in adult populations but have not focused on this process in children. In the present study, we analyzed spontaneous T lymphocyte (PBT) apoptosis in the peripheral blood of children with central nervous system tuberculosis (CNS TB), before and after chemotherapy, and compared the results with healthy controls. METHODS: A case-control study was conducted from January 2002 to June 2009. It included 18 children with CNS TB and 17 healthy controls. Spontaneous apoptosis of PBTs, including CD4+, CD8+ and CD8+/CD28+ T cells, was evaluated after 24 and 72 h of culture in complete medium, using the Annexin V detection test. Analysis was conducted before and after chemotherapy, and expression of the apoptotic markers CD95 (Fas) and Fas ligand (FasL) was evaluated. RESULTS: Higher percentages of apoptotic T cells and CD4 lymphocytes were isolated from children with acute phase CNS TB than from children in the control group (p < 0.05). This difference significantly decreased after 60 days of specific treatment. In children with CNS TB, high levels of Fas ligand expression were detected in lymphocyte populations, associated with a high percentage of Fas positive cells, before and after treatment. In contrast to the CD4+ apoptosis profile, we did not find any significant difference in total CD8+ cell apoptosis between children with acute phase disease and the control group. However, the percentage of apoptotic CD8+/CD28+ T cells was significantly higher in the children with acute phase disease than in the healthy controls. CONCLUSIONS: Our findings indicate that CNS TB in pediatric patients increases the sensitivity of CD4 and CD8+/CD28+ T cells to apoptosis, suggesting a hypoergic status of this infection. This could play a key role in the immunopathogenesis of this complicated form of TB. Interestingly, specific chemotherapy is able to normalize both apoptosis sensitivity and T-cell activation.

A cross-sectional study assessing the relationship between BMI, asthma, atopy, and eNO among schoolchildren.

BACKGROUND: Increased body weight may influence airway inflammatory mechanisms. OBJECTIVE: To assess whether overweight-obesity (OW-O), evaluated as increased body mass index, is associated either with exhaled nitric oxide (eNO), a marker of airway inflammation, or with allergic sensitization in a large sample of children and adolescents. METHODS: A cross-sectional, epidemiological study was performed on a population sample of schoolchildren evaluating 708 subjects (age 10-16 years; BMI 13-39 kg/m(2)) by respiratory health questionnaire, skin prick tests, spirometry, and eNO measure. RESULTS: Prevalence rates were: OW-O 16.4%, asthma ever (A) 11.9%, and rhinoconjunctivitis (RC) 14.8%. Asthma ever and allergic sensitization were significantly more frequent among OW-O (21.0 and 51.6%) than in non-OW-O (10.2 and 37.0%, respectively). The forced expiratory volume in 1 second (FEV(1))/forced vital capacity (FVC) ratio was not significantly different between OW-O and non-OW-O. Exhaled NO (median and interquartile range) was 15.3 (11.2-23.1) ppb in the overall sample, 20.3 (12.9-35.8) ppb among allergic subjects, and 13.9 (10.6-18.3) ppb among nonallergic subjects (P<.0001). No significant difference between OW-O and non OW-O subjects was found in eNO levels. Similarly, OW-O subjects with A or RC did not show significantly higher eNO levels than non-OW-O. In a logistic regression model, presence of allergic sensitization, A, and RC, and not OW-O, were significant predictors of increased eNO. CONCLUSIONS: In children, OW-O was not associated with increased eNO levels, but it was an independent risk factor for asthma and allergic sensitization.

Proportional Venn diagram and determinants of allergic respiratory diseases in Italian adolescents.

Large variations in prevalence of atopy and allergic diseases are reported worldwide in children, but in epidemiological studies the use of skin prick tests (SPT) and spirometry along with questionnaires is not common in the Mediterranean Area. The present work was aimed at evaluating the prevalence of current asthma (CA), rhinoconjunctivitis (RC), and eczema (E), with atopy and respiratory function, and the role of risk factors for allergic respiratory diseases. A total of 2150 Italian schoolchildren were cross-sectionally investigated through respiratory questionnaire, SPT, and spirometry. A proportional Venn diagram quantified the distribution of CA, RC, and E, stratifying for allergic sensitization to show differences in prevalence of allergic diseases among subjects with and without positive SPT. CA prevalence was 4.2%, RC 17.9%, and E 5.3%. CA and RC increased, while E decreased, with respect to previous local studies. Allergic sensitization prevalence (evaluated as positive response to at least one SPT) was 39.2%. A double Venn diagram identified 15 categories. Atopic CA was threefold more frequent than non-atopic CA. Atopic vs non-atopic RC and E were 9.6% vs 10.3% and 2.0% vs 3.3%, respectively. Atopic vs non-atopic RC associated with CA were 1.6% vs 0.5%; the same figures for RC associated with E were 0.8% vs 1.3%. Asymptomatic atopic subjects were 27.0%. Atopy, RC, parental asthma, and environmental risk factors were associated with CA. Atopy and environmental factors were risk factors also for RC. Asthma and traffic exposure were linked to reduced lung function. Respiratory allergic diseases are still increasing and largely concomitant in Italian adolescents. Atopy is more important for CA than RC. Avoiding exposures to measured environmental risk factors would prevent 41% of current asthma and 34% of rhinoconjunctivitis.

Pleural mesothelial cells express both BLT2 and PPARalpha and mount an integrated response to pleural leukotriene B4.

Leukotriene B(4) (LTB(4)) plays a crucial role in the recruitment of neutrophils into the pleural space. We identified for the first time the mechanisms by which LTB(4) interacts with mesothelial cells and recruits neutrophils in the pleural compartment. Primary pleural mesothelial cells express both the proinflammatory receptor for LTB(4) BLT2, and the anti-inflammatory receptor for LTB(4), PPARalpha. Parapneumonic pleural effusions highly increase BLT2 expression and, via BLT2 activation, increase the adhesion between mesothelial cells and neutrophils and the expression of ICAM-1 on mesothelial cells. The block of PPARalpha further increases both cell adhesion and ICAM-1 expression. BLT2 activation promotes the activation, on mesothelial cells, of STAT-1 but not the activation of NF-kappaB transcription factor. The increase of ICAM-1 expression is achieved via increased tyrosine phosphorylation activity since herbimycin, a tyrosine kinase inhibitor, reduces and since Na orthovanadate, a tyrosine phosphatase inhibitor, further increases ICAM-1 expression. This study demonstrates that pleural mesothelial cells, expressing both proinflammatory and anti-inflammatory LTB(4) receptors, are able to mount an integrated response to LTB(4) with a prevalence of BLT2 activities in the presence of an inflammatory milieu within the pleura.

Cigarette smoke increases Toll-like receptor 4 and modifies lipopolysaccharide-mediated responses in airway epithelial cells.

Airway epithelium is emerging as a regulator of innate immune responses to a variety of insults including cigarette smoke. The main goal of this study was to explore the effects of cigarette smoke extracts (CSE) on Toll-like receptor (TLR) expression and activation in a human bronchial epithelial cell line (16-HBE). The CSE increased the expression of TLR4 and the lipopolysaccharide (LPS) binding, the nuclear factor-kappaB (NF-kappaB) activation, the release of interleukin-8 (IL-8) and the chemotactic activity toward neutrophils. It did not induce TLR2 expression or extracellular signal-regulated signal kinase 1/2 (ERK1/2) activation. The LPS increased the expression of TLR4 and induced both NF-kappaB and ERK1/2 activation. The combined exposure of 16-HBE to CSE and LPS was associated with ERK activation rather than NF-kappaB activation and with a further increase of IL-8 release and of chemotactic activity toward neutrophils. Furthermore, CSE decreased the constitutive interferon-inducible protein-10 (IP-10) release and counteracted the effect of LPS in inducing both the IP-10 release and the chemotactic activity toward lymphocytes. In conclusion, cigarette smoke, by altering the expression and the activation of TLR4 via the preferential release of IL-8, may contribute to the accumulation of neutrophils within the airways of smokers.

Elevated expression of prostaglandin receptor and increased release of prostaglandin E2 maintain the survival of CD45RO+ T cells in the inflamed human pleural space.

Throughout the body, the distribution and differentiation of T-cell subsets varies in a way that optimizes host responses. The role of activation-induced cell death (AICD) in altering the distribution of T-lymphocyte subsets at an immune or inflammatory sites has been unexplored. The objective of this study was to assess whether pleural macrophages modulate AICD of specific pleural T-lymphocyte subsets. We found that pleural T-lymphocytes spontaneously undergo apoptosis, which is associated to increased expression of both FAS and FAS ligand, to decreased expression of Bcl 2 and to caspase 8 and 3 activation. While pleural T lymphocytes were partly protected from apoptosis, autologous peripheral blood T lymphocytes increased their apoptosis when cultured with exudative pleural fluids. Pleural CD45RO(+) T cells, in comparison to pleural CD45RA(+) T cells, were more susceptible to apoptosis, but were preferentially protected by exudative pleural fluids. Pleural prostaglandin E 2 (PGE(2)) was implicated in protecting T-lymphocytes from apoptosis because exudative pleural T lymphocytes highly express PGE(2) receptors, and because exudative pleural fluid contained high concentrations of PGE(2). Activated pleural macrophages released PGE(2) and reduced the spontaneous apoptosis of pleural T lymphocytes and depletion of PGE(2) from pleural fluids decreased this protective effect. This study demonstrates that PGE(2), released in the pleural fluids following pleural macrophage activation, prolongs the survival of specific T-cell subsets, resulting in differentiation of the T-cell repertoire within the inflamed pleural space.

Diorganotin(IV) and triorganotin(IV) complexes of meso-tetra(4-sulfonatophenyl)porphine induce apoptosis in A375 human melanoma cells.

The cytotoxic effect of several diorganotin(IV) and triorganotin(IV)-meso-tetra(4-sulfonatophenyl)porphine derivatives was tested and only the (Bu(2)Sn)(2)TPPS and the (Bu(3)Sn)(4)TPPS showed cytotoxicity on A375 human melanoma cells. To examine the pathway of (Bu(2)Sn)(2)TPPS or (Bu(3)Sn)(4)TPPS induced A375 cell death, DNA fragmentation analysis, Annexin V binding and PI uptake as well as caspases activation analysis by Western blot were carried out. A375 cells treated exhibited several typical characteristics of apoptosis. Both the (Bu(2)Sn)(2)TPPS and the (Bu(3)Sn)(4)TPPS compounds activate caspase-8 and caspase-9 leading to caspase-3 activation. Thus, we propose that these two porphirin derivatives lead to the apoptosis of human melanoma cells via both death receptor-mediated and mitochondrial apoptotic pathways.

Synergistic effects of fluticasone propionate and salmeterol on in vitro T-cell activation and apoptosis in asthma.

BACKGROUND: In asthma T cells are characterized by an increased activation state and by reduced apoptosis. OBJECTIVE: Because the clinical efficacy of inhaled corticosteroids combined with long-acting beta 2 -agonists has been widely demonstrated in asthma, we studied, in vitro, the effect of fluticasone propionate (FP) and salmeterol alone and in combination on the activation and apoptosis of peripheral blood T cells (PBTs), on the expression of phosphorylated nuclear factor kappaB inhibitor (IkappaBalpha), and on the nuclear translocation of glucocorticoid receptor (GR) in PBTs from asthmatic subjects. METHODS: Apoptosis was evaluated on the basis of annexin V binding, whereas the expression of caspases 8 and 3 and phosphorylated IkappaBalpha, as well as the nuclear translocation of the GR, were evaluated by means of Western blot analysis. RESULTS: FP alone increases and salmeterol alone does not affect T-cell apoptosis. The combination of FP and salmeterol significantly increases PBT apoptosis in comparison with FP alone. FP at the lower concentration, when combined with salmeterol, is equivalent to FP at the higher concentration in inducing PBT apoptosis. The synergy in the induction of cell apoptosis is associated with more efficient activation of caspases 8 and 3. FP plus salmeterol is also able to synergistically reduce the expression of phosphorylated IkappaBalpha, thus limiting nuclear factor kappaB activation. The synergy was related to an increased nuclear translocation of the GR. CONCLUSION: This study shows that the combination of FP and salmeterol is able to control PBT activation in asthmatic patients more efficiently than FP alone and with a lower concentration of steroids.

Increased prostaglandin E2 concentrations and cyclooxygenase-2 expression in asthmatic subjects with sputum eosinophilia.

BACKGROUND: Prostaglandin E2 (PGE2) is known to be produced within human airways, but it is not clear whether in airway diseases it can play a deleterious or a beneficial role. Recently it has been reported that PGE2 can enhance eosinophil survival in vitro. OBJECTIVE: To evaluate whether the concentrations of PGE2 in asthmatic airways correlate with the number of eosinophils and can be responsible for eosinophil-enhanced survival and to identify the cyclooxygenase isoform contributing to the synthesis of PGE2 by cells present in asthmatic airways. METHODS: Reversed-phase high-performance liquid chromatography and/or specific radioimmunoassay was used to measure PGE2 concentrations in induced sputum supernatants from 14 control and 30 asthmatic subjects. Correlations between concentrations of PGE2 and the number of eosinophils in induced sputum were evaluated. Expression of cyclooxygenase-2 (COX-2) in induced sputum cells was determined by immunocytochemistry, and the effect of COX-2 inhibition on PGE2 production was evaluated with the use of radiolabeled arachidonic acid. The effects on eosinophil apoptosis by PGE2 or induced sputum supernatants were studied by using peripheral blood eosinophils obtained by negative immunomagnetic selection. RESULTS: PGE2 concentrations resulted in elevated samples from asthmatic subjects and directly correlated with the percentage of eosinophils and the concentrations of eosinophilic cationic protein. Immunostaining for COX-2 showed enhanced expression in macrophages of asthmatic subjects when compared with control subjects, and the use of a specific COX-2 inhibitor provided evidence that PGE2 synthesis was the result of COX-2 enzymatic activity in asthma-induced sputum cells. Supernatant from induced sputum of asthmatic subjects with high eosinophil counts caused a decreased apoptosis of peripheral blood eosinophils when compared with control subjects, and immunoprecipitation of PGE2 significantly reverted this phenomenon, suggesting that PGE2 was present in biologically relevant concentrations in induced sputum. CONCLUSIONS: The results obtained suggest that COX-2 expression in alveolar macrophages from asthmatic subjects may contribute to enhanced eosinophil survival through an increased PGE2 production.

Biologically active intercellular adhesion molecule-1 is shed as dimers by a regulated mechanism in the inflamed pleural space.

Intercellular adhesion molecule-1 (ICAM-1) is an adhesion molecule that plays a crucial role in cell-cell interactions involved in the recruitment of cells and immune responses. Under some circumstances, ICAM-1 is found as a soluble protein that has the potential to influence the nature of immunoinflammatory responses. By examining cells and fluid from the pleural compartment of patients with cancer, tuberculosis, and congestive heart failure, the cellular source, conformation, control, and biological activity of soluble ICAM-1 (sICAM-1) were investigated. The results suggest that dimeric sICAM-1 was released locally in the pleural compartment of tuberculous and malignant effusions. sICAM-1 was shed from preexpressed surface ICAM-1 rather than produced de novo, and both CD45-positive leukocytes and cytokeratin-positive epithelial and mesothelial cells expressed ICAM-1, suggesting multiple cellular sources for sICAM-1. The expression of sICAM-1 was regulated because pleural macrophages caused release of sICAM-1 via a tumor necrosis factor-alpha-dependent mechanism. The functional significance of sICAM-1 was demonstrated by showing that pleural sICAM-1 interfered with conjugate formation between LAK cells and K562 cells, suggesting that pleural sICAM-1 plays an immunosuppressive role by inhibiting adhesion of cytotoxic lymphocytes and tumor cells. Thus, sICAM-1 is shed from the surface of cells in a regulated manner and has the potential to influence the immune response in the pleural space.