Interleukin-8 is a potent mediator of eosinophil chemotaxis through endothelium and epithelium

MAIT Cells Modulate Innate Immune Cells and Inhibit Colon Cancer Growth

Mucosal-associated invariant T (MAIT) cells are innate-like T cells that can be activated by microbial antigens and cytokines and are abundant in mucosal tissues including the colon. MAIT cells have cytotoxic and pro-inflammatory functions and have potentials for use as adoptive cell therapy. However, studies into their anti-cancer activity, including their role in colon cancer, are limited. Using an animal model of colon cancer, we show that peritumoral injection of in vivo-expanded MAIT cells into RAG1-/- mice with MC38-derived tumors inhibits tumor growth compared to control. Multiplex cytokine analyses show that tumors from the MAIT cell-treated group have higher expression of markers for eosinophil-activating cytokines, suggesting an association between eosinophil recruitment and tumor inhibition. In a human peripheral leukocyte co-culture model, we show that leukocytes stimulated with MAIT ligand show an increase in eotaxin-1 production and activation of eosinophils, associated with increased cancer cell killing. In conclusion, we show that MAIT cells have a protective role in a murine colon cancer model, associated with modulation of the immune response to cancer, potentially involving eosinophil-associated mechanisms. Our results highlight the potential of MAIT cells for non-donor restricted colon cancer immunotherapy.

Therapeutic Potential of Chungsangboha-tang for the Treatment of Asthma: A Review of Preclinical and Clinical Studies

In traditional Korean medicine, Chungsangboha-tang (CSBHT) and its modified forms are used to treat various respiratory disorders, including asthma. This study aimed to identify research trends, clarify the effectiveness of CSBHT and related prescriptions, and lay a foundation for future research. We conducted a literature review using PubMed, Embase, Google Scholar, Oriental Medicine Advanced Searching Integrated System, National Digital Science Links, Korean Medical Database, Wanfang Data, and Chinese National Knowledge Infrastructure databases. We analyzed 25 studies, including 5 in vitro studies, 6 animal studies, and 14 human studies. Many studies evaluated the efficacy of CSBHT and its related prescriptions, including experimental studies on its effectiveness in asthma. The main mechanism of action involves the anti-inflammatory effect caused by the regulation of various immune cells, cytokines, and chemokines. In addition, clinical trials on asthma reported the benefits of CSBHT and its related prescriptions. However, there has been no randomized controlled study of clinical trials on the clinical effectiveness of CSBHT in asthma. Therefore, large-scale randomized controlled studies should be conducted in the future.

Systematic Characterization of the Disruption of Intestine during Liver Tumor Progression in the xmrk Oncogene Transgenic Zebrafish Model

The crosstalk between tumors and their local microenvironment has been well studied, whereas the effect of tumors on distant tissues remains understudied. Studying how tumors affect other tissues is important for understanding the systemic effect of tumors and for improving the overall health of cancer patients. In this study, we focused on the changes in the intestine during liver tumor progression, using a previously established liver tumor model through inducible expression of the oncogene xmrk in zebrafish. Progressive disruption of intestinal structure was found in the tumor fish, displaying villus damage, thinning of bowel wall, increase in goblet cell number, decrease in goblet cell size and infiltration of eosinophils, most of which were observed phenotypes of an inflammatory intestine. Intestinal epithelial cell renewal was also disrupted, with decreased cell proliferation and increased cell death. Analysis of intestinal gene expression through RNA-seq suggested deregulation of genes related to intestinal function, epithelial barrier and homeostasis and activation of pathways in inflammation, epithelial mesenchymal transition, extracellular matrix organization, as well as hemostasis. Gene set enrichment analysis showed common gene signatures between the intestine of liver tumor fish and human inflammatory bowel disease, the association of which with cancer has been recently noticed. Overall, this study represented the first systematic characterization of the disruption of intestine under the liver tumor condition and suggested targeting intestinal inflammation as a potential approach for managing cancer cachexia.

Proton Pump Inhibitor Therapy for Eosinophilic Esophagitis: History, Mechanisms, Efficacy, and Future Directions

Over the past decade, the role of proton pump inhibitor (PPI) medication has evolved from a diagnostic tool for Eosinophilic Esophagitis (EoE), by excluding patients with PPI responsive esophageal eosinophilia (PPI-REE), to a therapy for EoE. This transition resulted from the Updated International Consensus Diagnostic Criteria for Eosinophilic Esophagitis: Proceedings of the Appraisal of Guidelines for Research and Evaluation II (AGREE) Conference to support PPI therapy for EoE in children and adults. Additional recent advances have suggested a role for genetic variations that might impact response to PPI therapy for EoE. This review article will explore a brief background of EoE, the evolution of PPI therapy for EoE and its proposed mechanisms, efficacy and safety in children and adults, and considerations for future PPI precision medicine in patients with EoE.

Peculiarities of blood coagulation disorders in patients with COVID-19

Aim. To study the relationship of hemostatic disorders with inflammation and estimate their role in the course and outcomes of COVID-19. Materials and methods. We examined 215 consecutive patients with moderate and severe forms of acute COVID-19. The patients were on anticoagulants and immunosuppressive drugs. Hemostasis was assessed using the thrombodynamics assay, thromboelastography, fibrinogen and D-dimer levels, prothrombin time, and soluble fibrin-monomer complexes (ethanol gelation test). The hemostatic parameters were correlated with hematological and biochemical tests, including markers of inflammation (C-reactive protein, interleukins 6 and 8), as well as with the disease severity and outcomes. Results. Laboratory signs of coagulopathy were revealed in the vast majority of the cases. Despite the use of low-molecular-weight heparins in the prophylactic and therapeutic doses, coagulopathy in COVID-19 manifested predominantly as hypercoagulability that correlated directly with the systemic inflammation and metabolic changes due to liver and kidney dysfunction. A direct relationship was found between the grade of coagulopathy and the severity of COVID-19, including comorbidities and the mortality. The chronometric hypocoagulability observed in about 1/4 cases was associated with a high level of C-reactive protein, which may decelerate coagulation in vitro and thereby mask the true inflammatory thrombophilia. Persistent hyperfibrinogenemia and high D-dimer in the absence of consumption coagulopathy suggest the predominance of local and/or regional microthrombosis over disseminated intravascular coagulation. Conclusion. The results obtained substantiate the need for laboratory monitoring of hemostasis and active prophylaxis and treatment of thrombotic complications in COVID-19.

Analysis of tear inflammatory molecules and clinical correlations in evaporative dry eye disease caused by meibomian gland dysfunction

Purpose

To compare the levels of inflammatory molecules in tear samples between patients with meibomian gland dysfunction (MGD)-related evaporative dry eye (EDE) and healthy subjects and to analyze the correlations between the levels of tear inflammatory molecules and ocular surface parameters.

Methods

A total of 30 MGD-related EDE patients (48 eyes) and ten healthy volunteers (15 eyes) were enrolled. Dry eye-related examinations and questionnaires were obtained from all participants. The levels of nine inflammatory molecules were determined through multiplex bead analysis.

Results

Inflammatory molecules including ICAM-1, IFN-γ, CXCL8/IL-8, IL-6, TNF-α and IL-12p70 were detected in 100% of the patients, while IL-1α, IL-1β and IL-10 were detected in 56.25%, 13.60% and 45.83% of the patients, respectively. Moreover, ICAM-1, IL-8, IL-6, TNF-α, IL-12p70 and IFN-γ were detected in 86.67–100% of the healthy subjects, and the detection rates of IL-10, IL-1α and IL-1β were below 50%. The levels of IL-8, IL-6, IFN-γ and ICAM-1 were significantly higher in the patient group compared with the control group. In addition, IL-8 and IL-6 were negatively correlated with Schirmer I test. Besides, IFN-γ was negatively correlated with tear film breakup time. Furthermore, ICAM-1 and IL-6 were positively correlated with meibography score.

Conclusions

Collectively, patients with MGD-related EDE had higher levels of inflammatory molecules in their tears, and some molecules were correlated with ocular surface parameters. These findings suggested that inflammation played an important role in MGD-related EDE, and several inflammatory molecules could be used in the diagnosis and the treatment of MGD-related EDE.

Decreased lung function is associated with elevated ferritin but not iron or transferrin saturation in 42,927 healthy Korean men: A cross-sectional study

Objectives

Though elevated ferritin level and decreased lung function both predispose people to cardio-metabolic disease, few reports have investigated the association between them. Furthermore, it remains unclear whether the association reflects a change in iron stores or an epiphenomenon reflecting metabolic stress. Therefore, we looked for possible associations between ferritin, iron, and transferrin saturation (TSAT) and lung function to clarify the role of iron-related parameters in healthy men.

Methods

We conducted a cohort study of 42,927 healthy Korean men (mean age: 38.6 years). Percent predicted forced expiratory volume in one second (FEV1%) and forced vital capacity (FVC%) were categorized into quartiles. Adjusted odds ratios (aORs) and 95% confidence intervals (using the highest quartile as reference) were calculated for hyperferritinemia, high iron, and high TSAT after controlling for potential confounders.

Results

The median ferritin level was 199.8 (141.5–275.6) ng/mL. The prevalence of hyperferritinemia (defined as >300 ng/mL) was 19.3%. Subjects with hyperferritinemia had lower FEV1% and FVC% than those with normal ferritin level with a slight difference, but those were statistically significant (99.22% vs.99.61% for FEV1%, p = 0.015 and 98.43% vs. 98.87% for FVC, p = 0.001). However, FEV1/FVC ratio was not significantly different between groups (P = 0.797). Compared with the highest quartile, the aORs for hyperferritinemia across decreasing quartiles were 1.081 (1.005–1.163), 1.100 (1.007–1.200), and 1.140 (1.053–1.233) for FEV1% (p for trend = 0.007) and 1.094 (1.018–1.176), 1.101 (1.021–1.188), and 1.150 (1.056–1.252) for FVC% (p for trend = 0.001). However, neither FEV1% nor FVC% was associated with iron or TSAT.

Conclusions

Hyperferritinemia was associated with decreased lung function in healthy Korean men, but iron and TSAT were not. Longitudinal follow-up studies are required to validate our findings.

Transforming growth factor-β1 and eosinophil-derived neurotoxins contribute to the development of work-related respiratory symptoms in bakery workers

Background

In baker's asthma previous studies suggest that adaptive and innate immunity are involved in the development of work-related respiratory symptoms (WRS), where we hypothesized that epithelial cells derive airway inflammation through modulating the release of inflammatory cytokines. Thus, we conducted this study to investigate the role of epithelial cell-derived cytokines in the development of WRS among bakery workers.

Methods

We recruited 385 wheat-exposed subjects with WRS (WRS+)/without WRS (WRS-) working in a single industry and 243 unexposed controls from Ajou Medical Center (Suwon, South Korea). Levels of epithelial cell-derived cytokines (interleukin [IL-8], transforming growth factor-β1 [TGF-β1], eotaxin-2) and inflammatory mediators (eosinophil-derived neurotoxins [EDN]) in sera or cell-free supernatants were measured by ELISA. Human airway epithelial cells (HAECs), A549, were stimulated by wheat flour extracts and co-cultured with peripheral blood neutrophils isolated from 4 asthmatic patients.

Results

Serum TGF-β1 levels were significantly lower in exposed subjects than in unexposed controls, in the WRS+ group than in the WRS- group (P < 0.001 for each). The WRS+ group had a significantly higher level of serum EDN than the WRS- group (P < 0.001). Serum TGF-β1 and EDN levels predicted the development of WRS in exposed subjects (area under the curve [AUC] = 0.719, 72.4% sensitivity/70% specificity; AUC = 0.759, 78.6% sensitivity/60% specificity). From wheat-stimulated HAECs, TGF-β1 release peaked at 6 hours after wheat exposure, while eotaxin-2 peaked at 12 hours. Co-culture of HAECs with neutrophils did not affect TGF-β1 release.

Conclusions

Our results suggest that TGF-β1 may contribute to develop type-2 airway inflammation and WRS. Serum TGF-β1/EDN levels may be potential serum biomarkers for predicting WRS among bakery workers.

Hypomethylation of the IL8 promoter in nasal epithelial cells of patients with chronic rhinosinusitis with nasal polyps

BACKGROUND

IL-8 is an important chemokine implicated in the pathogenesis of chronic rhinosinusitis (CRS), but little is known about epigenetic regulation of IL8 in the pathogenesis of CRS.

OBJECTIVE

We sought to investigate the relationship between the DNA methylation level in the IL8 proximal promoter and CRS in Han Chinese subjects.

METHODS

Patients with chronic rhinosinusitis with nasal polyps (CRSwNP; n = 187), patients with chronic rhinosinusitis without nasal polyps (CRSsNP; n = 89), and control subjects (n = 57) were enrolled in 2 independent cohorts. Purified human nasal epithelial cells from each participant were assessed for percentage DNA methylation of CpG sites in the IL8 proximal promoter by using bisulfite pyrosequencing and for functional aspects of methylation status by using in vitro assays.

RESULTS

DNA methylation of CpG sites 1, 2, and 3, respectively, in the IL8 proximal promoter was significantly decreased in human nasal epithelial cells of patients with CRSwNP compared with that in patients with CRSsNP (P < .001) and control subjects (P < .001). Percentage of DNA methylation of the CpG3 site was correlated negatively with both tissue eosinophilic cationic protein (P < .01) and myeloperoxidase (P < .05) levels. IL-1β (P < .001) and TNF-α (P < .01) significantly increased IL8 expression accompanied by a reduction in methylation at the CpG3 site (P < .001). Electrophoretic mobility shift assays demonstrated that methylation status of CpG3 changed the binding of octamer-binding transcription factor 1 and nuclear factor κB.

CONCLUSION

Decreased DNA methylation of particularly CpG sites in the IL8 proximal promoter might play a role in the pathogenesis of CRSwNP.

Elevated cytokine levels in tears and saliva of patients with primary Sjögren's syndrome correlate with clinical ocular and oral manifestations

Investigating cytokines in tear fluid and saliva may offer valuable information for understanding the pathogenesis of primary Sjögren's syndrome (pSS). Cytokine profiles in both tear fluid and saliva of pSS patients, non-Sjögren's syndrome (non-SS) subjects with sicca symptoms, and healthy controls without sicca complaints were analysed. Furthermore, relationships associating the severity of clinical ocular and oral manifestations with the upregulated cytokines were assessed. In tear fluid, pSS patients showed elevated levels of IL-1ra, IL-2, IL-4, IL-8, IL-12p70, IL-17A, IFN-γ, IP-10, MIP-1b, and Rantes compared to non-SS subjects and healthy controls. The increased cytokine levels (except IP-10) correlated significantly with reduced tear production, less stable tear film, and greater ocular surface damage. In saliva, pSS patients had a higher IP-10 level, which correlated with higher candida score; and an elevated MIP-1a level, which correlated significantly with lower unstimulated and stimulated whole saliva secretion rates. The upregulated cytokines identified in tear fluid and saliva of pSS patients show a clear interplay between innate and adaptive immune responses that may contribute to disease pathogenesis. The increase of IP-10 and MIP in both tears and saliva further emphasises the essential role of macrophages and innate immunity in pSS.

Effects of vitamin D on inflammatory and oxidative stress responses of human bronchial epithelial cells exposed to particulate matter

BACKGROUND

Particulate matter (PM) pollutant exposure, which induces oxidative stress and inflammation, and vitamin D insufficiency, which compromises immune regulation, are detrimental in asthma.

OBJECTIVES

Mechanistic cell culture experiments were undertaken to ascertain whether vitamin D abrogates PM-induced inflammatory responses of human bronchial epithelial cells (HBECs) through enhancement of antioxidant pathways.

METHODS

Transcriptome analysis, PCR and ELISA were undertaken to delineate markers of inflammation and oxidative stress; with comparison of expression in primary HBECs from healthy and asthmatic donors cultured with reference urban PM in the presence/absence of vitamin D.

RESULTS

Transcriptome analysis identified over 500 genes significantly perturbed by PM-stimulation, including multiple pro-inflammatory cytokines. Vitamin D altered expression of a subset of these PM-induced genes, including suppressing IL6. Addition of vitamin D suppressed PM-stimulated IL-6 production, although to significantly greater extent in healthy versus asthmatic donor cultures. Vitamin D also differentially affected PM-stimulated GM-CSF, with suppression in healthy HBECs and enhancement in asthmatic cultures. Vitamin D increased HBEC expression of the antioxidant pathway gene G6PD, increased the ratio of reduced to oxidised glutathione, and in PM-stimulated cultures decreased the formation of 8-isoprostane. Pre-treatment with vitamin D decreased CXCL8 and further decreased IL-6 production in PM-stimulated cultures, an effect abrogated by inhibition of G6PD with DHEA, supporting a role for this pathway in the anti-inflammatory actions of vitamin D.

CONCLUSIONS

In a study using HBECs from 18 donors, vitamin D enhanced HBEC antioxidant responses and modulated the immune response to PM, suggesting that vitamin D may protect the airways from pathological pollution-induced inflammation.

Newly divided eosinophils limit ozone-induced airway hyperreactivity in nonsensitized guinea pigs

Ozone causes vagally mediated airway hyperreactivity and recruits inflammatory cells, including eosinophils, to lungs, where they mediate ozone-induced hyperreactivity 1 day after exposure but are paradoxically protective 3 days later. We aimed to test the role of newly divided eosinophils in ozone-induced airway hyperreactivity in sensitized and nonsensitized guinea pigs. Nonsensitized and sensitized guinea pigs were treated with 5-bromo-2-deoxyuridine (BrdU) to label newly divided cells and were exposed to air or ozone for 4 h. Later (1 or 3 days later), vagally induced bronchoconstriction was measured, and inflammatory cells were harvested from bone marrow, blood, and bronchoalveolar lavage. Ozone induced eosinophil hematopoiesis. One day after ozone, mature eosinophils dominate the inflammatory response and potentiate vagally induced bronchoconstriction. However, by 3 days, newly divided eosinophils have reached the lungs, where they inhibit ozone-induced airway hyperreactivity because depleting them with antibody to IL-5 or a TNF-α antagonist worsened vagally induced bronchoconstriction. In sensitized guinea pigs, both ozone-induced eosinophil hematopoiesis and subsequent recruitment of newly divided eosinophils to lungs 3 days later failed to occur. Thus mature eosinophils dominated the ozone-induced inflammatory response in sensitized guinea pigs. Depleting these mature eosinophils prevented ozone-induced airway hyperreactivity in sensitized animals. Ozone induces eosinophil hematopoiesis and recruitment to lungs, where 3 days later, newly divided eosinophils attenuate vagally mediated hyperreactivity. Ozone-induced hematopoiesis of beneficial eosinophils is blocked by a TNF-α antagonist or by prior sensitization. In these animals, mature eosinophils are associated with hyperreactivity. Thus interventions targeting eosinophils, although beneficial in atopic individuals, may delay resolution of airway hyperreactivity in nonatopic individuals.

Pentraxin 3 deletion aggravates allergic inflammation through a TH17-dominant phenotype and enhanced CD4 T-cell survival

Background

Pentraxin 3 (PTX3) is a multifunctional molecule that plays a nonredundant role at the crossroads between pathogen clearance, innate immune system, matrix deposition, female fertility, and vascular biology. It is produced at sites of infection and inflammation by both structural and inflammatory cells. However, its role in allergen-induced inflammation remains to be tested.

Objective

We sought to determine the effect of Ptx3 deletion on ovalbumin (OVA)–induced allergic inflammation in a murine model of asthma.

Methods

Bronchoalveolar lavage fluid was collected from patients with severe asthma and healthy subjects, and the level of PTX3 was determined by using ELISA. Ptx3^+/+ and Ptx3^−/− mice were sensitized and challenged with OVA and bronchoalveolar lavage fluid, and the lungs were collected for assessing inflammation. Lung tissue inflammation and mucus production were assessed by means of flow cytometry and hematoxylin and eosin and periodic acid-Schiff staining, respectively. flexiVent was used to determine airway resistance to methacholine in these mice.

Results

Here we report that mice with severe asthma and OVA-sensitized/challenged mice had increased PTX3 levels in the lungs compared with healthy control mice. Mice lacking PTX3 have exaggerated neutrophilic/eosinophilic lung inflammation, mucus production, and airway hyperresponsiveness in an experimental model of OVA-induced asthma. Furthermore, OVA-exposed lung Ptx3^−/− CD4 T cells exhibit an increased production of IL-17A, an effect that is accompanied by an increased signal transducer and activator of transcription 3 phosphorylation, reduced IL-2 production, and enhanced activation and survival. Also, we observed an increase in numbers of IL-6– and IL-23–producing dendritic cells in OVA-exposed Ptx3^−/− mice compared with those in wild-type control mice.

Conclusion

Altogether, PTX3 deficiency results in augmented airway hyperresponsiveness, mucus production, and IL-17A–dominant pulmonary inflammation, suggesting a regulatory role of PTX3 in the development of allergic inflammation.

Altered esophageal histamine receptor expression in Eosinophilic Esophagitis (EoE): implications on disease pathogenesis

Eosinophilic Esophagitis (EoE) is a chronic allergic disorder, whose pathobiology is incompletely understood. Histamine-producing cells including mast cells and basophils have been implicated in EoE. However, very little is currently known about the role of histamine and histamine receptor (HR) expression and signaling in the esophageal epithelium. Herein, we characterized HR (H1R, H2R, H3R, and H4R) expression in human esophageal biopsies and investigate the role of histamine signaling in inducible cytokine expression in human esophageal epithelial cells in vitro. HR expression was quantified in esophageal biopsies from non-EoE control (N = 23), inactive EoE (<15 eos/hpf, N = 26) and active EoE (>15 eos/hpf, N = 22) subjects using qRT-PCR and immunofluorescent localization. HR expression and histamine-mediated cytokine secretion were evaluated in human primary and telomerase-immortalized esophageal epithelial cells. H1R, H2R, and H4R expression were increased in active EoE biopsies compared to inactive EoE and controls. H2R was the most abundantly expressed receptor, and H3R expression was negligible in all 3 cohorts. Infiltrating eosinophils expressed H1R, H2R, and H4R, which contributed to the observed increase in HR in active subjects. H1R and H2R, but not H3R or H4R, were constitutively expressed by primary and immortalized cells, and epithelial histamine stimulation induced GM-CSF, TNFα, and IL-8, but not TSLP or eotaxin-3 secretion. Epithelial priming with the TLR3 ligand poly (I:C) induced H1R and H2R expression, and enhanced histamine-induced GM-CSF, TNFα, and IL-8 secretion. These effects were primarily suppressed by H1R antagonists, but unaffected by H2R antagonism. Histamine directly activates esophageal epithelial cytokine secretion in vitro in an H1R dependent fashion. However, H1R, H2R and H4R are induced in active inflammation in EoE in vivo. While systemic antihistamine (anti-H1R) therapy may not induce clinical remission in EoE, our study suggests that further study of histamine receptor signaling in EoE is warranted and that targeting of additional histamine receptors may lead to novel treatment strategies for this important disease.

Accumulation of eosinophils in the infundibulum of the bovine oviduct just after ovulation

This study was to investigate the localization and distribution of eosinophils (EOS) in the bovine oviduct throughout the estrous cycle. Histological studies revealed more abundant EOS in the infundibula of the oviducts ipsilateral to the preovulatory dominant follicle and the ovulated ovary. The number of EOS was higher in the infundibula of the oviducts ipsilateral to the ovulated ovary than those of the oviducts contralateral to the ovulated ovary. The infundibula of the oviducts ipsilateral to the preovulatory dominant follicle had higher number of EOS than those of the oviducts ipsilateral to the mid-cycle corpus luteum. The number of EOS in the isthmus, but not in the ampulla, was higher in the outer layers (tunica muscularis and tunica serosa) than in the inner layers (tunica mucosa and tunica submucosa) during the estrous cycle. Thus, the EOS number varied with the region of the bovine oviduct, with greater number in the infundibula of the oviduct ipsilateral to the ovulated ovary, suggesting the impact of ovulation.

Exposure and toxicity assessment of ultrafine particles from nearby traffic in urban air in seoul, Korea

OBJECTIVES

We investigated the particle mass size distribution and chemical properties of air pollution particulate matter (PM) in the urban area and its capacity to induce cytotoxicity in human bronchial epithelial (BEAS-2B) cells.

METHODS

To characterize the mass size distributions and chemical concentrations associated with urban PM, PM samples were collected by a 10-stage Micro-Orifice Uniform Deposit Impactor close to nearby traffic in an urban area from December 2007 to December 2009. PM samples for in vitro cytotoxicity testing were collected by a mini-volume air sampler with PM10 and PM2.5 inlets.

RESULTS

The PM size distributions were bi-modal, peaking at 0.18 to 0.32 and 1.8 to 3.2 µm. The mass concentrations of the metals in fine particles (0.1 to 1.8 µm) accounted for 45.6 to 80.4% of the mass concentrations of metals in PM10. The mass proportions of fine particles of the pollutants related to traffic emission, lead (80.4%), cadmium (69.0%), and chromium (63.8%) were higher than those of other metals. Iron was the dominant transition metal in the particles, accounting for 64.3% of the PM10 mass in all the samples. We observed PM concentration-dependent cytotoxic effects on BEAS-2B cells.

CONCLUSIONS

We found that exposure to PM2.5 and PM10 from a nearby traffic area induced significant increases in protein expression of inflammatory cytokines (IL-6 and IL-8). The cell death rate and release of cytokines in response to the PM2.5 treatment were higher than those with PM10. The combined results support the hypothesis that ultrafine particles from vehicular sources can induce inflammatory responses related to environmental respiratory injury.

Modulation of NK cell autocrine-induced eosinophil chemotaxis by interleukin-15 and vitamin D(3): a possible NK-eosinophil crosstalk via IL-8 in the pathophysiology of allergic rhinitis

Natural killer cells (NK) secrete eosinophilotactic cytokines, however, whether they contribute to eosinophil chemotaxis by secreting IL-8 is not known. We investigated the ability of CD56+CD3-ve (NK cells) to induce chemotaxis of peripheral blood eosinophils from allergic rhinitis (AR) patients, through IL-8 secretion, and the effects of IL-15, the NK cell proactivating cytokine, and calcitriol: 1α, 25-dihydroxy Vitamin D₃ (vitamin D₃), the immunomodulator agent, in this scenario. Herein, it is shown that supernatants from unstimulated NK cells exhibited chemotactic activity against eosinophil. This effect was significantly augmented by IL-15 (1 ng/mL) treatment, resulting in an increase in the chemotactic index of approximately 3 folds and was abrogated by neutralizing antibody (Ab) to IL-8 in a dose-dependent fashion. The amount of IL-8 secreted by NK cells was increased by IL-15 treatment from levels of 88.64 ± 21.5 to 178.9 ± 23.6 Pg/mL and was significantly reduced by 10⁻⁶ M vitamin D₃ to levels of 59.2 ± 16.3 Pg/mL. Our results indicate a novel inflammatory crosstalk between NK cells and eosinophils via IL-15/IL-8 axis that can be modulated by vitamin D₃.

Immune markers in breast milk and fetal and maternal body fluids: a systematic review of perinatal concentrations

Breastfeeding represents the continued exposure of the infant to the maternal immune environment.Uterine, perinatal, and postnatal exposure to immune factors may contribute to an infant’s risk of developing immune-mediated disorders, including allergies. A PubMed search was conducted to review studies in humans and analyze concentrations of immune markers (TGF-beta, IFN-gamma, eotaxin, CCL5, CXCL10, TNF-alpha, MCP-1, IL-1beta, IL-4, IL-5, IL-6,IL-8, IL-10, IL-12, IL-13, sCD14, sIgA, IgG4, IgM) found in maternal serum, amniotic fluid, cord serum, colostrum, transition and mature milk. Concentrations of immune markers showed large variations across samples and studies. Reports documented conflicting results. Small sample sizes, differences in population characteristics, inconsistent sample collection times, and various sample collection and measurement methods may have led to wide variations in the concentrations of immune markers. Studies analyzing the associations between immune markers in maternal fluids and infant allergies remain inconclusive because of gaps in knowledge and a lack of standardized methods.

Transcriptomic analysis of the temporal host response to skin infestation with the ectoparasitic mite Psoroptes ovis

Background

Infestation of ovine skin with the ectoparasitic mite Psoroptes ovis results in a rapid cutaneous immune response, leading to the crusted skin lesions characteristic of sheep scab. Little is known regarding the mechanisms by which such a profound inflammatory response is instigated and to identify novel vaccine and drug targets a better understanding of the host-parasite relationship is essential. The main objective of this study was to perform a combined network and pathway analysis of the in vivo skin response to infestation with P. ovis to gain a clearer understanding of the mechanisms and signalling pathways involved.

Results

Infestation with P. ovis resulted in differential expression of 1,552 genes over a 24 hour time course. Clustering by peak gene expression enabled classification of genes into temporally related groupings. Network and pathway analysis of clusters identified key signalling pathways involved in the host response to infestation. The analysis implicated a number of genes with roles in allergy and inflammation, including pro-inflammatory cytokines (IL1A, IL1B, IL6, IL8 and TNF) and factors involved in immune cell activation and recruitment (SELE, SELL, SELP, ICAM1, CSF2, CSF3, CCL2 and CXCL2). The analysis also highlighted the influence of the transcription factors NF-kB and AP-1 in the early pro-inflammatory response, and demonstrated a bias towards a Th2 type immune response.

Conclusions

This study has provided novel insights into the signalling mechanisms leading to the development of a pro-inflammatory response in sheep scab, whilst providing crucial information regarding the nature of mite factors that may trigger this response. It has enabled the elucidation of the temporal patterns by which the immune system is regulated following exposure to P. ovis, providing novel insights into the mechanisms underlying lesion development. This study has improved our existing knowledge of the host response to P. ovis, including the identification of key parallels between sheep scab and other inflammatory skin disorders and the identification of potential targets for disease control.

CXCR2 antagonists for the treatment of pulmonary disease

Chemokines have long been implicated in the initiation and amplification of inflammatory responses by virtue of their role in leukocyte chemotaxis. The expression of one of the receptors for these chemokines, CXCR2, on a variety of cell types and tissues suggests that these receptors may have a broad functional role under both constitutive conditions and in the pathophysiology of a number of acute and chronic diseases. With the development of several pharmacological, immunological and genetic tools to study CXCR2 function, an important role for this CXC chemokine receptor subtype has been identified in chronic obstructive pulmonary disease (COPD), asthma and fibrotic pulmonary disorders. Interference with CXCR2 receptor function has demonstrated different effects in the lungs including inhibition of pulmonary damage induced by neutrophils (PMNs), antigen or irritant-induced goblet cell hyperplasia and angiogenesis/collagen deposition caused by lung injury. Many of these features are common to inflammatory and fibrotic disorders of the lung. Clinical trials evaluating small molecule CXCR2 antagonists in COPD, asthma and cystic fibrosis are currently underway. These studies hold considerable promise for identifying novel and efficacious treatments of pulmonary disorders.

Immunology

The concept of forbidden foods that should not be eaten goes back to the Garden of Eden and apart from its religious meanings it may also have foreshadowed the concept of foods that can provoke adverse reactions. Thus we could say that allergic diseases have plagued mankind since the beginning of life on earth. The prophet Job was affected by a condition that following the rare symptoms described by the Holy Bible might be identified as a severe form of atopic dermatitis (AD). The earliest record of an apparently allergic reaction is 2621 B.C., when death from stinging insects was first described by hieroglyphics carved into the walls of the tomb of Pharaoh Menes depicting his death following the sting of a wasp. In 79 A.D., the death of the Roman admiral Pliny the Elder was ascribed to the SO₂-rich gases emanating from the eruption of Mount Vesuvius. Hippocrates (460–377 B.C.) was probably the first to describe how cow’s milk (CM) could cause gastric upset and hives, proposing dietetic measures including both treatment and prevention for CM allergy.

OK205 regulates production of inflammatory cytokines in HMC-1 cells

OK205 is a traditional Korean prescription containing water-soluble chitosan, glucosamine HCl, chondroitin sulfate, and extract of herbal medicine, and has been used commercially to treat rheumatoid arthritis (RA). Because infiltrated mast cells and their mediators may contribute to the initiation and progression of the inflammatory process and matrix degradation of RA, we tested the inhibitory effects of OK205 on cytokine production in a human mast cell line (HMC-1 cells). Production of tumor necrosis factor-alpha was significantly decreased to 0.091+/-0.010 ng/ml after treatment of HMC-1 cells with OK205 100 microg/ml. The inhibition rate was about 43.57%. In addition, production of interleukin-6 in OK205 1 pg/ml-treated cells was 2.779+/-0.071 ng/ml, and the inhibition rate was about 50.22%. However, OK205 did not significantly inhibit the production of interleukin-8. These findings may help in understanding the mechanism of action of OK205, leading to control of mast cells in inflammatory conditions like RA.

Contribution of IL-1 beta and TNF-alpha to the initiation of the peripheral lung response to atmospheric particulates (PM10)

Alveolar macrophages (AM) play a key role in clearing atmospheric particulates from the lung surface and stimulating epithelial cells to produce proinflammatory mediators. The present study examines the role of "acute response" cytokines TNF-alpha and IL-1 beta released by AM exposed to ambient particulate matter with a diameter of <10 microm (PM(10)) in amplifying the proinflammatory mediator expression by A549 cells and human bronchial epithelial cells (HBEC). The results showed that supernatants from human AM incubated 24 h with PM(10) (100 microg/ml) contained more TNF-alpha, IL-1 beta, granulocyte-macrophage colony stimulating factor, IL-6, and IL-8 than nonexposed AM supernatants. The 3-h treatment of A549 cells with PM(10)-exposed AM supernatants increased TNF-alpha, IL-1 beta, IL-8, regulated on activation normal T-cells expressed and secreted (RANTES), and leukemia inhibitory factor mRNA compared with the treatment with nonexposed AM supernatants and, compared with untreated A549 cells, additionally increased ICAM-1 and monocyte chemotactic protein-1 mRNA. Preincubating PM(10)-exposed AM supernatants with anti-IL-1 beta antibodies reduced all the above mediators as well as VEGF mRNA expression (P < 0.05), while anti-TNF-alpha antibodies were less effective (P > 0.05), and the combination of the two antibodies most effective. When HBEC were treated similarly, anti-TNF-alpha antibodies had the greatest effect. In A549 cells PM(10)-exposed AM supernatants increased NF-kappa B, activator protein (AP)-1 and specificity protein 1 binding, while anti-TNF-alpha and anti-IL-1 beta antibodies reduced NF-kappa B and AP-1 binding. We conclude that AM-derived TNF-alpha and IL-1 beta provide a major stimulus for the production of proinflammatory mediators by lung epithelial cells and that their relative importance may depend on the type of epithelial cell target.

Capillarization of hepatic sinusoid by liver endothelial cell-reactive autoantibodies in patients with cirrhosis and chronic hepatitis

The special features of liver sinusoidal endothelium (LSE) are crucial for normal liver physiology. Cirrhotic livers, especially in primary biliary cirrhosis (PBC), are characterized by transformation of the LSE into a continuous, vascular type. The transformation is important for disease progression and explains some of the pathological hallmarks of the cirrhotic liver. Here, we investigated the presence of liver sinusoidal endothelial cell (LSEC)-reactive autoantibodies (Abs) in the sera of patients with autoimmune liver diseases, and assessed the ability of these Abs to transform LSE into vascular endothelium. Compared to healthy individuals (9%), significantly higher numbers of patients with PBC (59%; P < 0.001) and autoimmune hepatitis (AIH) (32%; P < 0.05) had Abs against LSECs. Incubation of primary LSEC cultures with F(ab')(2) fragments of anti-LSEC Abs isolated from sera of patients with PBC and AIH, induced 1) cell surface expression of vascular endothelium-associated markers, CD31, and factor VIII-related antigen; 2) significant production of fibronectin, laminin and collagen type IV; 3) loss of fenestrae, formation of tight junctions and Weibel-Palade bodies. Deposition of immunoglobulins on LSECs were found in liver biopsies of AIH and PBC patients. Thus, anti-LSEC autoAbs transform LSE into a vascular type and may therefore play an important role in the development of hepatocellular failure and portal hypertension in PBC and AIH patients.

The effect of recombinant interleukin-8 on eosinophils' and neutrophils' migration in vivo and in vitro

BACKGROUND

Interleukin-8 (IL-8) is a chemokine that causes chemotaxis of neutrophils, eosinophils and lymphocytes in vitro; however, its role as a chemoattractant in allergic inflammation is unclear. The objective of this study was to investigate the effect of nasal instillation of IL-8 on the influx of inflammatory cells.

METHODS

Twelve patients suffering from seasonal allergic rhinitis hypersensitive to grass pollens, with average age 30.1 +/- 2.67 years were challenged both with diluent for IL-8 and IL-8 on a subsequent day, in two phases: before the pollen season (unprimed mucosa) and during the season (primed mucosa). The number of neutrophils, eosinophils and myeloperoxydase (MPO) levels in the nasal fluid collected after IL-8 or placebo challenge were determined.

RESULTS

Challenge with IL-8 of primed nasal mucosa induced a significant influx of neutrophils (29 x 10(4) cells/ml at 0.5 h, 251 x 10(4) at 2 h and 334 x 10(4) at 3 h). Number of eosinophils in comparison with diluent challenge was not significant. There was no difference in MPO levels in the nasal lavage between IL-8 and diluent challenge of unprimed and primed mucosa. We did not find the relationship between MPO levels and the neutrophils number in the lavage (rank Spearman factor, RS = 0.258, P = 0.42).

CONCLUSION

We have demonstrated that IL-8 causes influx of neutrophils but not eosinophils into nasal mucosa in vivo. MPO level seems to be of little value as a marker of neutrophil influx into nasal mucosa.

CCR3 is essential for skin eosinophilia and airway hyperresponsiveness in a murine model of allergic skin inflammation

The CC chemokine receptor 3 (CCR3) is expressed by eosinophils, mast cells, and Th2 cells. We used CCR3(-/-) mice to assess the role of CCR3 in a murine model of allergic skin inflammation induced by repeated epicutaneous sensitization with ovalbumin (OVA), and characterized by eosinophil skin infiltration, local expression of Th2 cytokines, and airway hyperresponsiveness (AHR) to inhaled antigen. Eosinophils and the eosinophil product major basic protein were absent from the skin of sham and OVA-sensitized CCR3(-/-) mice. Mast cell numbers and expression of IL-4 mRNA were normal in skin of CCR3(-/-) mice, suggesting that CCR3 is not important for infiltration of the skin by mast cells and Th2 cells. CCR3(-/-) mice produced normal levels of OVA-specific IgE, and their splenocytes secreted normal amounts of IL-4 and IL-5 following in vitro stimulation with OVA, indicating effective generation of systemic Th2 helper responses. Recruitment of eosinophils to lung parenchyma and bronchoalveolar lavage (BAL) fluid was severely impaired in CCR3(-/-) mice, which failed to develop AHR to methacholine following antigen inhalation. These results suggest that CCR3 plays an essential role in eosinophil recruitment to the skin and the lung and in the development of AHR.

Human mast cell and airway smooth muscle cell interactions: implications for asthma

Asthma is characterized by inflammation, hyperresponsiveness, and remodeling of the airway. Human mast cells (HMCs) play a central role in all of these changes by releasing mediators that cause exaggerated bronchoconstriction, induce human airway smooth muscle (HASM) cell proliferation, and recruit and activate inflammatory cells. Moreover, the number of HMCs present on asthmatic HASM is increased compared with that on nonasthmatic HASM. HASM cells also have the potential to actively participate in the inflammatory process by synthesizing cytokines and chemokines and expressing surface molecules, which have the capacity to perpetuate the inflammatory mechanisms present in asthma. This review specifically examines how the mediators of HMCs have the capacity to modulate many functions of HASM; how the synthetic function of HASM, particularly through the release and expression of stem cell factor, has the potential to influence HMC number and activation in an extraordinarily potent and proinflammatory manner; and how these interactions between HMCs and HASM have potential consequences for airway structure and inflammation relevant to the disease process of asthma.

Thrombin regulates chemokine induction during human retinal pigment epithelial cell/monocyte interaction

Thrombin, an important clotting factor, extravasates at sites of blood-retina barrier breakdown that is often associated with many retinal diseases. Here we investigated the effects of thrombin on human retinal pigment epithelial (HRPE) cells, monocytes, and HRPE cell/monocyte co-cultures. Thrombin induced secretion and mRNA expression of HRPE interleukin (IL)-8 and monocyte chemoattractant protein-1 (MCP-1). Thrombin also enhanced IL-8 and MCP-1 by HRPE cell/monocyte co-cultures, by apparently enhancing cell-cell contact mechanisms. The thrombin effects on IL-6 secretion were similar to those on chemokine secretion. Thrombin-induced chemokines by co-cultures were inhibited by anti-tumor necrosis factor-alpha (TNF-alpha) antibody, but not by anti-IL-1beta antibody. TNF-alpha was detected in cell lysates of monocytes detached from HRPE cells after co-culture stimulation with thrombin. HRPE cells mainly produced these chemokines. However, thrombin generally potentiated exogenous IL-1beta- and TNF-alpha-induced chemokine production by HRPE cells, monocytes, and co-cultures. Interferon-gamma potentiated chemokine secretion by co-cultures with or without thrombin. Our results indicate that thrombin may cause leukocyte recruitment by inducing HRPE cell and monocyte chemokine and by enhancing HRPE cell/monocyte interactions, in part because of monocyte TNF-alpha induction, suggesting important mechanisms for ocular inflammation during blood-retina barrier breakdown and intra-ocular hemorrhage.

Effect of endothelin antagonism on the production of cytokines in eosinophilic airway inflammation

Endothelin (ET)-1 has been launched as an important mediator in bronchial asthma, which is an eosinophilic airway inflammation. However, the interplay between ET-1 and other proinflammatory mediators during the development of airway inflammation has not been elucidated. We wanted to study 1) whether the production of ET-1 precedes the production of other proinflammatory mediators and 2) whether ET-1 stimulates the production of these mediators within the airways. These hypotheses were studied during the development of an eosinophilic airway inflammation in rats. The increase in ET-1 mRNA level in lung tissue preceded the increase in mRNA levels of tumor necrosis factor-alpha, interleukin (IL)-1beta, and IL-8. Treatment of the animals with the ET receptor antagonist bosentan resulted in a substantial decrease in the concentrations of tumor necrosis factor-alpha, IL-4, IL-1beta, interferon-gamma, and ET-1 in bronchoalveolar lavage fluid. In conclusion, the synthesis of ET-1 as measured by increased mRNA level precedes the synthesis of other proinflammatory cytokines of importance for the development of an eosinophilic airway inflammation, and ET antagonism inhibits the production of these mediators within the airways. Whether treatment with ET antagonists will prove beneficial for patients with eosinophilic airway inflammations like bronchial asthma is not yet known.

IL-4 and IL-13 stimulate human bronchial epithelial cells to release IL-8

Cytokine networks are important in regulating the traffic of inflammatory cells in the airways. Interleukin-8 (IL-8) released by human bronchial epithelial cells (HBECs) is thought to be of particular importance in attracting neutrophils and monocytes to sites of inflammation. Increased release of IL-8 by HBECs in response to Th-1 cytokines such as TNF alpha and IL-1 beta may be an important pathophysiologic pathway. The present study was designed to explore the role of the Th2 cytokine IL-4 and the functionally related interleukins IL-10, and IL-13 on the regulation of IL-8 release by HBECs. HBECs (passage 4-6) were cultured in LHC9/RPMI and when confluent cells were stimulated in unsupplemented medium LHCD/RPMI by IL-4, IL-10, and IL-13 at 10 ng/ml concentration for all cytokines. TNF alpha stimulation was used as a positive control. After 24 hours supernatants were collected and tested for IL-8 by a sandwich ELISA. Unstimulated HBECs spontaneously released limited amounts of IL-8 (11 +/-1 pM) and significantly increased cytokine production in response to IL-4 (42 +/- 1 pM), IL-13 (30 +/- 1 pM) and TNF (128 +/- 11 pM). Stimulation with IL-10 (11 +/- pM) did not change basal production of IL-8. When HBECs were co-stimulated with IL-4 plus TNF, the production of IL-8 was further increased (204 +/- 5 pM). In contrast, IL-10 attenuated the effect of TNF during co-stimulation (82 +/- 5 pM). IL-13 did not affect the release of IL-8 induced by TNF (111 +/- 9 pM). Northern blot analysis of IL-8 mRNA levels showed the highest induction of IL-8 mRNA in HBECs co-stimulated with TNF and IL-4. We conclude from our study that IL-4 directly induces IL-8 release from HBECs and amplifies the release of IL-8 in response to TNF alpha. IL-13 is less active and IL-10 has an inhibitory effect. Airway epithelial cells are able to interact, therefore, with products of both Th1 and Th2 cells with respect to modulating release of IL-8.

Diesel Exhaust Particles Induce NF-κB Activation in Human Bronchial Epithelial Cells In Vitro: Importance in Cytokine Transcription

Fine particles derived from diesel engines (diesel exhaust particles, DEP) have attracted attention, since their density in industrial countries seems related to the increased prevalence of pulmonary diseases. Previous studies have suggested that DEP have a potential to directly activate airway epithelial cells to produce and release inflammatory cytokines and mediators, and thus facilitate inflammatory responses in the lung. To elucidate the molecular mechanisms of their action, we studied here IL-8 gene expression, one of the important cytokines in inflammatory responses, by Northern blot analysis and run-on transcription assay. Suspended DEP (1–50 μg/ml) increased the steady state levels of IL-8 mRNA, which was suggested to be largely due to increased transcriptional rates. Electrophoretic mobility shift assay demonstrated that DEP induced increased binding to the specific motif of NF-κB, but not of transcription factor AP-1. The luciferase reporter gene assay using wild-type and mutated NF-κB-binding sequences showed that DEP-induced NF-κB activation was involved in IL-8 transcription. Finally, both N-acetylcysteine and pyrrolidine dithiocarbamate attenuated the action of DEP on IL-8 mRNA expression, suggesting that oxidant-mediated pathway might be involved in its processes. These results suggested that DEP activate NF-κB, which might be an important mechanism of its potential to increase the expression of inflammatory cytokines in vitro.

Fourteen-member macrolides inhibit interleukin-8 release by human eosinophils from atopic donors

Macrolide antibiotics such as erythromycin have been reported to be effective for asthma. However, the precise mechanisms of this effect remain unclear. We studied the effect of erythromycin, clarithromycin, josamycin, and other antibiotics on the release by eosinophils of interleukin-8 (IL-8), a potent chemokine for inflammatory cells, including eosinophils themselves. Human eosinophils were isolated from atopic patients, and the effects of the drugs on IL-8 release were evaluated. Only 14-member macrolides (erythromycin and clarithromycin) showed a concentration-dependent suppressive effect on IL-8 release (control, 100%; erythromycin at 1 microgram/ml, 67.82% +/- 3.45% [P < 0.01]; clarithromycin at 5 micrograms/ml, 56.81% +/- 9.61% [P < 0.01]). The effect was found at therapeutic concentrations and appeared to occur at the posttranscriprtional level. In contrast, a 16-member macrolide (josamycin) had no significant effect. We suggest that 14-member macrolides inhibit IL-8 release by eosinophils and may thereby prevent the autocrine cycle necessary for the recruitment of these cells into the airways.

The Role of Mast Cell Tryptase in Regulating Endothelial Cell Proliferation, Cytokine Release, and Adhesion Molecule Expression: Tryptase Induces Expression of mRNA for IL-1β and IL-8 and Stimulates the Selective Release of IL-8 from Human Umbilical Vein Endothelial Cells

Mast cells are found frequently in close proximity to blood vessels, and endothelial cells are likely to be exposed to high concentrations of their granule mediators. We have investigated the proinflammatory actions of the major mast cell product tryptase on HUVEC. Addition of purified tryptase was found to stimulate thymidine incorporation, but induced little alteration in cell numbers, suggesting it is not a growth factor for HUVEC. Expression of ICAM-1, VCAM-1, and E-selectin was not altered following incubation with tryptase, but the potent granulocyte chemoattractant IL-8 was released in a dose-dependent fashion in response to physiologically relevant concentrations, with maximal levels in supernatants after 24 h. The actions of tryptase on HUVEC were inhibited by heat inactivation of the enzyme, or by preincubating with the protease inhibitors leupeptin or benzamidine, suggesting a requirement for an intact catalytic site. Reverse-transcription PCR analysis indicated up-regulation of mRNA for IL-8 as well as for IL-1β in response to tryptase or TNF-α. However, tryptase was a more selective stimulus than TNF-α and did not induce increased expression of mRNA for granulocyte-macrophage CSF or stimulate the release of this cytokine. Leukocyte accumulation in response to tryptase may be mediated in part through the selective secretion of IL-8 from endothelial cells.

Chemokines: leucocyte recruitment and activation cytokines

Chemokines are a family of structurally related proteins that share the ability to induce migration of specific subsets of leucocytes. These specialised cytokines play a critical part in the generation of cellular inflammation, both in the protective responses to invading pathogens and in the pathological processes associated with infection and immune-mediated diseases. Chemokines are more than simple chemotactic factors, since they are also implicated in leucocyte activation, angiogenesis, and antimicrobial functions, including a protective role in HIV infection. These molecules provide potentially valuable targets for therapeutic intervention in a wide range of diseases.

Cytokines induce selective granulocyte chemotactic responses

Neutrophils, eosinophils and cytokines are important in allergic airway inflammatory responses. However, it is unclear how cytokines selectively influence neutrophils versus eosinophils to migrate to an inflammatory site. The cytokines, transforming growth factor-beta1 (TGF-beta1), interleukin (IL)-1alpha, IL-5, IL-8, granulocyte macrophage-colony stimulating factor (GM-CSF) and tumor necrosis factor-alpha (TNF-alpha), are released subsequent to allergic reactions and affect both neutrophil and eosinophil functions. We studied whether these cytokines differed in capacity to induce human neutrophil versus eosinophil migration through naked filters and human umbilical vein endothelial cell (HUVEC) and human pulmonary type II-like epithelial (A549) cell monolayers grown on filters. Dose-response experiments using all barriers were performed for each granulocyte and cytokine. TGF-beta1 did not induce granulocyte migration. IL-5 induced eosinophil migration only through naked filters. IL-1alpha stimulated neutrophil migration through cellular barriers, but not through naked filters. TNF-alpha and GM-CSF induced neutrophil and eosinophil migration through filters, but only neutrophil migration through cellular monolayers. Only IL-8 induced significant neutrophil and eosinophil migration; however, there were clear-cut differences between the neutrophilotactic and eosinophilotactic responses through all barriers employed. Thus, our data show that these cytokines induce distinct chemotactic responses for neutrophils versus eosinophils. Moreover, by using relevant cellular barriers versus naked filters, our data better examines the capability of these cytokines to induce selective granulocyte migration to an inflammatory site in lung diseases such as asthma.

Acid aspiration-induced lung injury in rabbits is mediated by interleukin-8-dependent mechanisms

Acid aspiration lung injury may be mediated primarily by neutrophils recruited to the lung by acid-induced cytokines. We hypothesized that a major acid-induced cytokine was IL-8 and that a neutralizing anti-rabbit-IL-8 monoclonal antibody (ARIL8.2) would attenuate acid-induced lung injury in rabbits. Hydrochloric acid (pH = 1.5 in 1/3 normal saline) or 1/3 normal saline (4 ml/kg) was instilled into the lungs of ventilated, anesthetized rabbits. The rabbits were studied for 6 or 24 h. In acid-instilled rabbits without the anti-IL-8 monoclonal antibody, severe lung injury developed in the first 6 h; in the long-term experiments, all rabbits died with lung injury between 12 and 14 h. In acid-instilled rabbits given the anti-IL-8 monoclonal antibody (2 mg/kg, intravenously) either as pretreatment (5 min before the acid) or as treatment (1 h after the acid), acid-induced abnormalities in oxygenation and extravascular lung water were prevented and extravascular protein accumulation was reduced by 70%; in the long-term experiments, anti-IL-8 treatment similarly protected lung function throughout the 24-h period. The anti-IL-8 monoclonal antibody also significantly reduced air space neutrophil counts and IL-8 concentrations. This study establishes IL-8 as a critical cytokine for the development of acid-induced lung injury. Neutralization of IL-8 may provide the first useful therapy for this clinically important form of acute lung injury.