The GALEN rhinosinusitis cohort: chronic rhinosinusitis with nasal polyps affects health-related quality of life.

BACKGROUND: Chronic rhinosinusitis (CRS) significantly affects health-related quality of life (HRQoL). Few multinational observational studies have evaluated the impact of CRS with nasal polyps (CRSwNP) on patients’ HRQoL. This study aimed to assess HRQoL outcomes (including analyses by disease severity and impact of comorbidities and refractory disease) in CRSwNP patients from a large European database. METHODOLOGY: Data were analysed from the Global Allergy and Asthma European Network (GALEN) Rhinosinusitis Cohort, including sociodemographic data, patient-reported disease severity (visual analogue scale), and scores on the 36-Item ShortForm Health Survey (SF-36) questionnaire. Differences in mean SF-36 scores were evaluated between patients with CRSwNP and population norms and between subgroups of interest (disease severity, comorbidity, and refractory disease, defined by a history of sinonasal surgery). RESULTS: Patients with CRSwNP (N = 445) had significantly lower mean SF-36 Physical Component Summary (PCS) and Mental Component Summary (MCS) scores vs population norms, demonstrating that CRSwNP negatively affects HRQoL. The presence of comorbidities affected HRQoL, as shown by significant differences in PCS scores in patients with asthma or non-steroidal antiinflammatory drug-exacerbated respiratory disease, compared with patients without asthma. Patients with moderate-to-severe disease had significantly lower PCS scores than patients with mild disease. Severe disease had a significant impact on MCS score. History of surgery had a clinically meaningful negative effect on HRQoL compared with no history of surgery. CONCLUSIONS: CRSwNP patients have significantly lower HRQoL compared with population norms. The impact is greater in patients with greater disease severity, comorbidities, or refractory disease.

The Global Allergy and Asthma European Network (GALEN rhinosinusitis cohort: a large European cross-sectional study of chronic rhinosinusitis patients with and without nasal polyps.

BACKGROUND: Chronic rhinosinusitis (CRS) is a common yet under-recognised chronic inflammatory disease of the nose and paranasal sinuses that is classified according to the presence (CRSwNP) or absence (CRSsNP) of nasal polyps. METHODS: This paper reports the methodology and descriptive results of the Global Allergy and Asthma European Network (GALEN) rhinosinusitis cohort. We established a large CRS cohort within the GALEN consortium (European FP6 research initiative) to identify inflammatory endotypes, the natural disease course, and its impact on health-related quality of life (HRQoL). Detailed information on the impact of CRS on HRQoL, comorbidity incidence, objective disease measures, and medical and surgical treatments were collected. RESULTS: This multicentre cross-sectional case-control study recruited 935 adults (869 eligible for analysis: 237 CRSsNP; 445 CRSwNP; 187 controls [reference group]). Comorbidities such as asthma, allergy, eczema, food allergy, urticaria, and chronic obstructive pulmonary disease were significantly more frequent in CRS patients. Nasal corticosteroids, antibiotics, and oral corticosteroids were the most common treatments. Significantly more CRSwNP patients reported previous sinonasal surgery. CONCLUSIONS: This study provides detailed information that facilitates studying CRS and its main phenotypes. However, patient distribution of this study does not necessarily reflect disease distribution in the general population.

Oropharyngeal squamous cell carcinoma induces an innate systemic inflammation, affected by the size of the tumour and the lymph node spread.

OBJECTIVES: Inflammation is known to be associated with the progression of cancer. The study was designed to characterise the systemic inflammation in patients with oropharyngeal squamous cell carcinoma (OPSCC) and investigate its relation to tumour size, ability to metastasise and HPV status. MATERIALS AND METHODS: Blood was obtained from 58 patients with OPSCC and 90 healthy controls and analysed with leucocyte differential count. RESULTS: The patients with OPSCC displayed an increased number of neutrophils and monocytes, whereas the lymphocytes were suppressed compared to the healthy controls. The neutrophils-to-lymphocyte ratio (NLR) and the monocyte-to-lymphocyte ratio (MLR) were calculated, and patients with large tumours exhibited high NLR and MLR. Further, patients with regional lymph node spread displayed a low NLR and MLR. Patients with HPV-positive tumours (n = 48) had a lower NLR than the patients (n = 8) with HPV-negative tumours. CONCLUSION: This study demonstrates that patients with OPSCC have an increased systemic inflammation that is affected by the HPV status, the size of the tumour and lymph node spread.

CD-sens can be a reliable and easy-to-use complement in the diagnosis of allergic rhinitis.

BACKGROUND: A reproducible standard for a graded allergen response in allergic rhinitis is lacking. The aim was to evaluate basophil allergen threshold sensitivity, CD-sens, as a diagnostic complement to nasal allergen challenge. METHODS: Twenty-six patients with a history of allergic rhinitis due to grass pollen were intranasally challenged and nasal symptom score and peak nasal inspiratory flow (PNIF) changes were determined after 15 min. A 20% decrease in PNIF or a symptom score ≥2 were considered a positive test. A blood sample for CD-sens was drawn before each challenge. Eighteen patients were tested twice. RESULTS: CD-sens agreed with the positive or negative nasal symptom score in 22/26 and PNIF in 24/26 patients. After the second challenge, 14/18 patients had the same symptom, 17/18 the same PNIF, while all had identical CD-sens classification. CONCLUSION: CD-sens appears to be a reproducible test for diagnosis of allergic rhinitis with great advantages also for follow-up of disease development and treatment effects.

Systemic up-regulation of TLR4 causes lipopolysaccharide-induced augmentation of nasal cytokine release in allergic rhinitis.

BACKGROUND: Allergic rhinitis is a systemic disorder, and it is clinically well recognized that it can be aggravated by infection. Activation of the innate immune system constitutes a critical element in the process. Toll-like receptors (TLRs) comprise a part of the innate immune system, and lipopolysaccharide (LPS)-induced activation of TLR4 represents bacterial-induced interactions in various model systems. The present study examines how TLR2 and TLR4 expression is affected by symptomatic allergic rhinitis, and if LPS added upon allergen affects nasal cytokine release. METHODS: In patients with pollen-induced allergic rhinitis and healthy non-allergic volunteers, nasal lavage (NAL), peripheral blood and bone marrow were sampled before and during the pollen season. TLR2 and TLR4 expression was determined flow cytometrically. Changes in the TLR receptor expression pattern were evaluated by a nasal challenge with allergen followed by LPS, or vice versa. Symptoms along with cells and cytokines in NAL were analyzed. RESULTS: TLR4 expression increased in leukocytes in NAL, peripheral blood and bone marrow during symptomatic allergic rhinitis. A similar increase was seen for TLR2 in neutrophils in blood. Nasal challenge with allergen followed by LPS augmented the release of IL-4, IL-5, IL-10, IL-13, IFN-γ and TNF-α. CONCLUSION: A systemic up-regulation of TLR4 in symptomatic allergic rhinitis may explain why LPS preceded by allergen increases nasal cytokine release.

NOD-like receptors in the human upper airways: a potential role in nasal polyposis.

BACKGROUND: Nucleotide-binding oligomerization domain (NOD)-like receptors (NLRs) are newly discovered cytosolic receptors belonging to the pattern-recognition receptor family. They detect various pathogen-associated molecular patterns, triggering an immune response. The knowledge about these receptors, and their role in health and disease, is limited. The aim of the present study was to characterize the expression of NOD1, NOD2, and NALP3 in the human upper airways. METHODS: Surgical samples were obtained from patients with tonsillar disease (n = 151), hypertrophic adenoids (n = 9), and nasal polyposis (n = 24). Nasal biopsies were obtained from healthy volunteers (n = 10). The expression of NOD1, NOD2, and NALP3 was analyzed using real-time PCR and immunohistochemistry. RESULTS: Expression of NOD1, NOD2, and NALP3 mRNA and protein were seen in all tissue specimens. The NLR mRNA was found to be higher in nasal polyps than in normal nasal mucosa, and local steroid treatment reduced the NLR expression in polyps. In contrast, tonsillar infection with Streptococcus pyogenes or Haemophilus influenzae did not affect the NLR expression. CONCLUSIONS: The present study demonstrates the presence of NLRs in several upper airway tissues and highlights a potential role of NLRs in chronic rhinosinusitis with polyps.

Reliability of EP3OS symptom criteria and nasal endoscopy in the assessment of chronic rhinosinusitis--a GA² LEN study.

BACKGROUND: The European Position Paper on Rhinosinusitis and Nasal Polyps (EP3OS) incorporates symptomatic, endoscopic, and radiologic criteria in the clinical diagnosis of chronic rhinosinusitis (CRS), while in epidemiological studies, the definition is based on symptoms only. We aimed to assess the reliability and validity of a symptom-based definition of CRS using data from the GA(2) LEN European survey. METHODS: On two separate occasions, 1700 subjects from 11 centers provided information on symptoms of CRS, allergic rhinitis, and asthma. CRS was defined by the epidemiological EP3OS symptom criteria. The difference in prevalence of CRS between two study points, the standardized absolute repeatability, and the chance-corrected repeatability (kappa) were determined. In two centers, 342 participants underwent nasal endoscopy. The association of symptom-based CRS with endoscopy and self-reported doctor-diagnosed CRS was assessed. RESULTS: There was a decrease in prevalence of CRS between the two study phases, and this was consistent across all centers (-3.0%, 95% CI: -5.0 to -1.0%, I(2) = 0). There was fair to moderate agreement between the two occasions (kappa = 39.6). Symptom-based CRS was significantly associated with positive endoscopy in nonallergic subjects, and with self-reported doctor-diagnosed CRS in all subjects, irrespective of the presence of allergic rhinitis. CONCLUSION: Our findings suggest that a symptom-based definition of CRS, according to the epidemiological part of the EP3OS criteria, has a moderate reliability over time, is stable between study centers, is not influenced by the presence of allergic rhinitis, and is suitable for the assessment of geographic variation in prevalence of CRS.

Genes regulating molecular and cellular functions in noninfectious nonallergic rhinitis.

BACKGROUND: Chronic noninfectious, nonallergic rhinitis (NINAR) is a complex syndrome with a principally unknown pathophysiology. New technology has made it possible to examine differentially expressed genes and according to network theory, genes connected by their function that might have key roles in the disease. METHODS: Connectivity analysis was used to identify NINAR key genes. mRNA was extracted from nasal biopsies from 12 NINAR patients and 12 healthy volunteers. Microarrays were performed using Affymetrix chips with 54 613 genes. Data were analysed with the Ingenuity Pathway System for organization of genes into annotated biological functions and, thereafter, linking genes into networks due to their connectivity. The regulation of key genes was confirmed with reverse transcription-polymerase chain reaction (RT-PCR). RESULTS: In all, 43 genes were differentially expressed. The functional analysis showed that these genes were primarily involved in cellular movement, haematological system development and immune response. Merging these functions, 10 genes were found to be shared. Network analysis generated three networks and two of these 'shared genes' in key positions, c-fos and cell division cycle 42 (Cdc42). These genes were upregulated in both the array and the RT-PCR analysis. CONCLUSION: Ten genes were found to be of pathophysiological interest for NINAR and of these, c-fos and Cdc42 seemed to be of specific interest due to their ability to interact with other genes of interest within this context. Although the role of c-fos and Cdc42 in upper airway inflammation remains unknown, they might be used as potential disease markers.

Nasal CpG oligodeoxynucleotide administration induces a local inflammatory response in nonallergic individuals.

BACKGROUND: We have previously demonstrated the presence of toll-like receptor 9 in the nasal mucosa of both healthy and allergic individuals. CpG motifs, found in bacterial and viral DNA, elicit strong immunostimulatory effects via this receptor. CpG is known to skew the immune system towards a T helper 1 (Th1) profile, thereby suppressing Th2-driven allergic responses. This study was designed to examine the effects of CpG administration in the human nose. METHODS: Twenty subjects, of whom 10 suffered from seasonal allergic rhinitis (AR), were challenged intranasally with CpG outside pollen season. Symptom scores, nasal airway resistance (NAR), and nasal and pulmonary nitric oxide (NO) levels were assayed prior to challenge and 30 min, 6, 24 and 48 h post challenge. The presence of leukocytes and various cytokines were analyzed in nasal lavage (NAL) fluids before and after CpG exposure. RESULTS: Increased NAR, nasal NO production and secretion of interleukin (IL)-1beta, IL-6, and IL-8 were seen after CpG exposure. Further analysis revealed that this inflammatory response was more marked in healthy subjects than among patients with AR, although a higher basal inflammatory response was recorded in the allergic group. In vitro experiments suggest that the effects induced by CpG are mediated by epithelial cells and neutrophils. CONCLUSION: Nasal administration of CpG induces a local airway inflammation, more distinct among healthy than allergic individuals. The reduced responsiveness to CpG in allergic patients might be related to the ongoing minimal persistent inflammation. Results from cytokine analyses reflect the ability of CpG to induce a pro-inflammatory Th1-like immune response.

Connectivity can be used to identify key genes in DNA microarray data: a study based on gene expression in nasal polyps before and after treatment with glucocorticoids.

CONCLUSIONS: The presented analysis of nasal polyposis using connectivity based on the PubGene literature co-citation network demonstrates that this tool can be used to identify key genes in DNA microarray studies of human polygenic diseases. OBJECTIVES: DNA microarray studies of complex diseases may reveal differential expression of hundreds of genes. According to network theory and studies of yeast cells, genes that are connected with several other genes appear to have key regulatory roles. This study aimed to examine if this principle can be translated to DNA microarray studies of human disease, using nasal polyposis as a base for the analysis. MATERIALS AND METHODS: The connectivity of differentially expressed genes from a previously described microarray study of nasal polyposis before and after treatment with glucocorticoids was determined. This was done using the literature co-citation network PubGene. RESULTS: In all, 166 genes were differentially expressed; 39 of these were previously defined as inflammatory and considered important for nasal polyposis. The connectivity of all differentially expressed genes was analysed using the PubGene literature co-citation network. Seventy-four of the 166 genes were connected to other genes. By contrast, the average number of connected genes among 100 sets of 166 randomly chosen genes was 31.5. A small number of the differentially expressed genes were highly connected, while most genes had few or no connections. This indicated a scale-free network. The most connected gene was interleukin-8, an inflammatory gene of known importance for nasal polyposis. Twenty-eight of the 74 connected genes were inflammatory (38%), compared with 11 of the 92 unconnected genes (12%), p < 0.0001. Since most evidence suggests that nasal polyps are inflammatory in their nature, this supports the hypothesis that connected genes have more disease relevance than unconnected genes.

Circulating eosinophils in asthma, allergic rhinitis, and atopic dermatitis lack morphological signs of degranulation.

BACKGROUND: In allergic diseases, eosinophils in affected tissues release granule proteins with cytotoxic, immunoregulatory, and remodelling-promoting properties. From recent observations, it may be assumed that eosinophils degranulate already in circulating blood. If degranulation occurs in the circulation, this could contribute to widespread systemic effects and provide an important marker of disease. OBJECTIVE: To determine the degranulation status of circulating eosinophils in common allergic diseases. METHODS: Using a novel approach of whole blood fixation and leucocyte preparation, the granule morphology of blood eosinophils from healthy subjects, non-symptomatic patients, symptomatic patients with asthma, asthma and Churg-Strauss syndrome, allergic rhinitis, and atopic dermatitis was evaluated by transmission electron microscopy (TEM) and eosinophil peroxidase (TEM) histochemistry. Plasma and serum levels of eosinophil cationic protein were measured by fluoroenzymeimmunoassay. Selected tissue biopsies were examined by TEM. RESULTS: Regardless of symptoms, circulating eosinophils from allergic patients showed the same granule morphology as cells from healthy subjects. The majority of eosinophil-specific granules had preserved intact electron-density (96%; range: 89-98%), while the remaining granules typically exhibited marginal coarsening or mild lucency of the matrix structure. Abnormalities of the crystalline granule core were rarely detected. Furthermore, granule matrix alterations were not associated with any re-localization of intracellular EPO or increase in plasma eosinophil cationic protein. By contrast, eosinophils in diseased tissues exhibited cytolysis (granule release through membrane rupture) and piecemeal degranulation (loss of granule matrix and core structures). CONCLUSION: In symptomatic eosinophilic diseases, circulating blood eosinophils retain their granule contents until they have reached their target organ.

Glucocorticoids suppress transcriptional up-regulation of bradykinin receptors in a murine in vitro model of chronic airway inflammation.

BACKGROUND: Glucocorticoids are effective drugs for controlling symptoms and airway inflammation in respiratory diseases such as asthma and chronic obstructive pulmonary disease. However, the mechanisms behind their effects are not fully understood. We have recently demonstrated that prolonged exposure to the pro-inflammatory mediator tumour necrosis factor-alpha (TNF-alpha) markedly enhanced contractile responses to des-Arg9-bradykinin (selective bradykinin B1 receptor agonist) and bradykinin (selective bradykinin B2 receptor agonist) in murine airways. This increase was paralleled with elevated mRNA levels for bradykinin B1 and B2 receptors, a process involving intracellular mitogen-activated protein kinase pathways. OBJECTIVE: To investigate the effects of glucocorticoids on the TNF-alpha up-regulated bradykinin B1 and B2 receptor response. METHODS: Tracheal segments from BALB/c J mice were cultured with and without TNF-alpha, in the absence and presence of the transcriptional inhibitor actinomycin D or the glucocorticoid, dexamethasone. The contractile response induced by des-Arg9-bradykinin and bradykinin was subsequently assessed in a myograph system and mRNA for bradykinin B1 and B2 receptors was quantified using real-time polymerase chain reaction. RESULTS: Actinomycin D abolished and dexamethasone concentration-dependently suppressed the TNF-alpha-induced enhancement of the des-Arg9-bradykinin and bradykinin responses. This was paralleled by a reduction of the mRNA expression for the bradykinin B1 and B2 receptors. CONCLUSION: The presented data suggests the involvement of transcriptional mechanisms in the up-regulation of bradykinin B1 and B2 receptors during asthmatic airway inflammation, as well as in their down-regulation following glucocorticoid treatment.

The CD19 molecule is crucial for MID-dependent activation of tonsillar B cells from children.

The Moraxella immunoglobulin (Ig) D-binding protein (MID) induces a strong proliferative response in human peripheral blood IgD+ B cells from adults isolated by positive selection using anti-CD19-conjugated microbeads. Here, we show that tonsillar B cells from children isolated with positive selection are unable to respond to MID stimulation. The proliferative response was very low or absent at various concentrations of MID tested and at different time points analysed, whereas the MID response of tonsillar B cells from adults isolated with positive selection was considerably higher. Tonsillar B cells from children isolated with positive selection responded to formalin-fixed preparations of Moraxella catarrhalis and Staphylococcus aureus Cowan strain I. In comparison to cells isolated with positive selection, a much higher proliferative response was recorded in tonsillar B cells from children isolated with negative selection, indicating that occupation of the CD19 molecule (i.e. positive selection) inhibited the response. Indeed, the addition of anti-CD19 monoclonal antibodies (MoAb) to MID-activated tonsillar B cells from children isolated with negative selection strongly inhibited the proliferative response. In contrast, anti-CD21 MoAb at the same concentration did only show a minor inhibition on the MID-induced response. Pre-incubation of tonsillar B cells isolated from children with anti-CD19 or anti-CD21 MoAb did not affect the binding of biotin-conjugated MID as analysed by flow cytometry. These results suggest that MID-activated tonsillar B cells from children have a strong requirement for signalling through the CD19 molecule. Future experiments will further reveal the importance of CD19 and possibly other molecules for optimal activation of tonsillar B cells isolated from both children and adults.

Intranasal steroids decrease eosinophils but not mucin expression in nasal polyps.

Increased mucin expression is a feature of nasal polyposis. Corticosteroids reduce polyp size and symptoms, but their effect on mucin production remains unknown. In this study, the effects of intranasal corticosteroids on MUC5AC mucin expression, nasal resistance, eosinophil and neutrophil infiltration, epidermal growth factor receptor (EGFR), interleukin (IL)-8, and tumour necrosis factor (TNF)-alpha expression was assessed in nasal polyps. In nine subjects, one nasal polyp was removed surgically before treatment and another was removed after 8 weeks of intranasal fluticasone (400 microg.day(-1)). Tissues were processed for in situ hybridisation and immunohistochemical staining. Described effects of fluticasone on nasal polyps (reduction in nasal resistance and in eosinophil infiltration) were evaluated. Morphometric analysis was performed to assess the effect of fluticasone on epithelial-, MUC5AC-, EGFR- and IL-8-stained areas, TNF-alpha-stained cells, and neutrophil numbers. Treatment with fluticasone decreased nasal resistance and intra-epithelial eosinophils. The MUC5AC-stained area in the epithelium was unchanged by treatment; MUC5AC mRNA expression was unaffected by treatment. EGFR-stained area, intra-epithelial neutrophil numbers, IL-8 and TNF-alpha expression were also unchanged by therapy. Intranasal fluticasone was effective in decreasing nasal airflow resistance and intra-epithelial eosinophils but had no effect on mucin or epidermal growth factor receptor expression or on neutrophil recruitment.

Impact of tobacco smoke on interleukin-16 protein in human airways, lymphoid tissue and T lymphocytes.

CD4(+) and CD8(+) lymphocytes are mobilized in severe chronic obstructive pulmonary disease (COPD) and the CD8(+) cytokine interleukin (IL)-16 is believed to be important in regulating the recruitment and activity of CD4(+) lymphocytes. In the current study, we examined whether tobacco smoke exerts an impact not only on IL-16 in the lower airways but also in CD4(+) or CD8(+) lymphocytes or in lymphoid tissue. The concentration of IL-16 protein was measured by enzyme-linked immunosorbent assay (ELISA) in concentrated bronchoalveolar lavage fluid (BALF) collected from 33 smokers with chronic bronchitis (CB), eight asymptomatic smokers (AS) and seven healthy never-smokers (NS). The concentrations of IL-16 and soluble IL-2 receptor alpha (sIL-2Ralpha) protein were also measured in conditioned medium from human blood CD4(+) and CD8(+) lymphocytes stimulated with tobacco smoke extract (TSE) in vitro. IL-16 mRNA was assessed in vitro as well, using reverse transcription-polymerase chain reaction (RT-PCR). Finally, the intracellular immunoreactivity for IL-16 protein (IL-16IR) was assessed in six matched pairs of palatine tonsils from smokers and non-smokers. BALF IL-16 was higher in CB and AS than in NS. TSE substantially increased the concentration of IL-16 but not sIL-2Ralpha in conditioned medium from CD4(+) and CD8(+) lymphocytes. There was no corresponding effect on IL-16 mRNA. IL-16IR in tonsils was lower in smokers than in non-smokers. The current findings demonstrate that tobacco smoke exerts a wide impact on the CD8(+) cytokine IL-16, in the airway lumen, in blood CD4(+) and CD8(+) lymphocytes and in lymphoid tissue. The effect on IL-16 release may be selective for preformed IL-16 in CD4(+) lymphocytes. New clinical studies are required to evaluate whether tobacco smoke mobilizes T lymphocytes via IL-16 in the lower airways and whether this mechanism can be targeted in COPD.

Pituitary adenylate cyclase-activating polypeptide, effects in the human nose.

BACKGROUND: Pituitary adenylate cyclase-activating peptide (PACAP) is a neuropeptide with strong vaso- and bronchodilator capacity. There is recent evidence that PACAP decreases the release of proinflammatory cytokines and we have previously shown that PACAP inhibits neutrophil chemotaxis in vitro, but little is known about the effects of PACAP in human upper and lower airways. OBJECTIVE: To investigate the effects of PACAP in the human upper respiratory tract focusing on vasodilatation/nasal airway resistance (NAR), neutrophil recruitment, plasma extravasation and endogenous production of IL-1-related mediators. METHODS: Surgical specimens from five patients (aged 19-55 years), obtained in conjunction with nasal surgery, were used for immunohistochemical localization of PACAP in the nasal mucosa. In seven, healthy, non-allergic, non-smoking subjects (aged 19-45 years), NAR was measured with rhinomanometry. Nasal lavage was performed, before and after intranasal application of PACAP (200 microL of a 1 microm PACAP solution in each nasal cavity), with and without the addition of histamine. Cells, albumin and IL-1-related mediators were analysed in nasal lavage. In addition, the effects on pulse, blood pressure, ECG and pulmonary function were evaluated. RESULTS: In the nasal mucosa, PACAP-like immunoreactive nerve fibres were seen close to blood vessels and seromucous glands. Application of PACAP in the nasal cavity increased NAR and augmented the increase in NAR induced by histamine. In addition, PACAP inhibited histamine-induced recruitment of neutrophils, increased plasma leakage and reduced the level of IL-1RA (an endogenously produced IL-1 receptor antagonist) in nasal lavage. Cardiovascular and pulmonary parameters were not affected. CONCLUSION: These results imply that PACAP is an important endogenous mediator in human upper airways, with a potential role as a regulator of vascular smooth muscle, secretion, plasma extravasation, neutrophil recruitment and cytokine activity.

Hemin, a heme oxygenase substrate analog, inhibits the cell surface expression of CD11b and CD66b on human neutrophils.

BACKGROUND: Neutrophils are signaled to sites of infection and inflammation by different chemotactic stimuli. In order to reach the airways they have to adhere to, and then migrate through, the endothelium of pulmonary vessels. Carbon monoxide (CO) is a gaseous mediator, endogenously produced in the human airways. Increased CO production has been demonstrated during airway inflammation and CO as well as hemin, a substrate for CO producing enzymes, has been shown to affect neutrophil migration. Our objective was to investigate if the neutrophil cell surface expression of CD11b, CD66b and CD63 was changed during intermittent allergic rhinitis and to establish whether CO could affect the expression of these markers of cellular activation. METHODS: Blood from 10 healthy volunteers was drawn and incubated with different concentrations of hemin. Blood from 12 other healthy volunteers and from 12 patients with intermittent allergic rhinitis was also drawn during grass pollen season. Neutrophils were then isolated from all these three sets, and their expression of CD antigens measured using flow cytometry. RESULTS: Patients with symptomatic intermittent allergic rhinitis exhibited lower levels of CD11b and CD66b on the neutrophil cell surface. Incubation with hemin decreased the expression of CD11b and CD66b. CD63 was generally weakly expressed and not significantly affected by hemin incubation. CONCLUSION: Our results demonstrate that expressions of neutrophil cell surface glycoproteins are changed during the season in patents with intermittent allergic rhinitis and that hemin, a substrate for CO production, may act as an inhibitor of neutrophil activation. This indicates a possible role for CO in the immune defense system.

The induction of carbon monoxide-mediated airway relaxation by PACAP 38 in isolated guinea pig airways.

Pituitary adenylate cyclase--activating peptide 38 (PACAP 38) displays several biologic activities relevant to obstructive airway disease. Carbon monoxide (CO) has recently emerged as a potent, endogenously produced mediator of bronchodilation. In this study, we have analyzed the occurrence of PACAP 38 and the corresponding occurrence of heme oxygenase (HO), the rate-limiting enzyme for CO production, in guinea pig trachea, using immunocytochemistry. We have also investigated whether the dilatory effects of PACAP 38 are dependent on CO, using an in vitro setup for tracheal studies. A moderate supply of PACAP-like immunoreactive nerve fibers was seen in association with tracheal smooth muscle. HO-like immunoreactivity was observed in the respiratory epithelium and in association with smooth muscle bundles. PACAP 38 induced a concentration-dependent relaxation of precontracted tracheal segments. This dilation was nearly abolished after pretreatment with zincprotoporphyrine, an inhibitor of heme oxygenase. The same effect was accomplished with Rp-8Br-cyclicGMPS, an inhibitor of cyclicGMP, whereas the nitric oxide synthase inhibitor N(G)-monomethyl-L-arginine had no effect on the PACAP 38--induced dilation. The presented data suggest that PACAP 38 can induce bronchodilation by means of a CO-dependent, cyclicGMP-related mechanism, thereby providing a link between neurotransmission and local CO release in the airway smooth muscle.

Helospectin, induces a potent relaxation of human airways in vitro.

Helospectin is a neuropeptide of the vasoactive intestinal polypeptide/secretin/glucagon family. Several members of this family display biological activities relevant to obstructive airway disease and although the literature in this area is rapidly expanding very little is known about the effects of helospectin. The smooth muscle relaxation induced by helospectin on human bronchi and pulmonary arteries were therefore assessed in vitro, using tissue baths. Helospectin induced a potent relaxation of human bronchi and since helospectin-like immunoreactive nerve fibers along with possible target receptors previously have been reported in the human lung, helospectin might play a role in endogenous regulation of airway tone.

Pituitary adenylate cyclase-activating peptide inhibits neutrophil chemotaxis.

Pituitary adenylate cyclase-activating peptide 38 (PACAP 38) is a neuropeptide that displays several biological effects of interest in the context of airway diseases such as asthma and chronic obstructive pulmonary disease. These effects include inhibition of airway and vascular smooth muscle tone as well as modulation of inflammatory cell activity. However, little is known about the effect of PACAP on granulocytes. The present study was designed to investigate if PACAP and the closely related peptide vasoactive intestinal peptide (VIP) could affect neutrophil migration. A standard 48 well chemotaxis chamber was used to assess the effects of PACAP on N-Formyl-L-methionyl-L-leucyl-L-phenylalanine (fMLP)-induced neutrophil chemotaxis and spontaneous random migration. PACAP 38 and VIP inhibited fMLP-induced human neutrophil chemotaxis. Furthermore, both peptides also exhibited a dose-related trend toward inhibiting the spontaneous, unstimulated migration of neutrophils. Since enhanced cell migration in cell chamber systems is reported to correlate with increased invasive properties in vivo, the presented inhibitory effects of PACAP 38 on neutrophil chemotaxis, supports the idea of an anti-inflammatory role for PACAP. This together with the well documented bronchodilatory capacity of PACAP might indicate a role for PACAP-agonists in future treatment of asthma and other inflammatory airway diseases.