How air pollution influences clinical management of respiratory diseases. A case-crossover study in Milan

Background Environmental pollution is a known risk factor for multiple diseases and furthermore increases rate of hospitalisations. We investigated the correlation between emergency room admissions (ERAs) of the general population for respiratory diseases and the environmental pollutant levels in Milan, a metropolis in northern Italy. Methods We collected data from 45770 ERAs for respiratory diseases. A time-stratified case-crossover design was used to investigate the association between air pollution levels and ERAs for acute respiratory conditions. The effects of air pollutants were investigated at lag 0 to lag 5, lag 0--2 and lag 3--5 in both single and multi-pollutant models, adjusted for daily weather variables. Results An increase in ozone (O3) levels at lag 3--5 was associated with a 78% increase in the number of ERAs for asthma, especially during the warm season. Exposure to carbon monoxide (CO) proved to be a risk factor for pneumonia at lag 0--2 and in the warm season increased the risk of ERA by 66%. A significant association was found between ERAs for COPD exacerbation and levels of sulphur dioxide (SO2), CO, nitrate dioxide (NO2), and particulate matter (PM10 and PM2.5). The multipollutant model that includes all pollutants showed a significant association between CO (26%) and ERA for upper respiratory tract diseases at lag 0--2. For chronic obstructive pulmonary disease (COPD) exacerbations, only CO (OR 1.19) showed a significant association. Conclusions Exposure to environmental pollution, even at typical low levels, can increase the risk of ERA for acute respiratory diseases and exacerbation of obstructive lung diseases in the general population

Cysteinyl leukotrienes: multi-functional mediators in allergic rhinitis

Cysteinyl leukotrienes (CysLTs) are a family of inflammatory lipid mediators synthesized from arachidonic acid by a variety of cells, including mast cells, eosinophils, basophils, and macrophages. This article reviews the data for the role of CysLTs as multi-functional mediators in allergic rhinitis (AR). We review the evidence that: (1) CysLTs are released from inflammatory cells that participate in AR, (2) receptors for CysLTs are located in nasal tissue, (3) CysLTs are increased in patients with AR and are released following allergen exposure, (4) administration of CysLTs reproduces the symptoms of AR, (5) CysLTs play roles in the maturation, as well as tissue recruitment, of inflammatory cells, and (6) a complex inter-regulation between CysLTs and a variety of other inflammatory mediators exists.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75432/1/j.1365-2222.2006.02498.x.pd

Nasal neutrophilia and release of myeloperoxidase induced by nasal challenge with platelet activating factor: Different degrees of responsiveness in atopic and nonatopic subjects

Background: Nasal challenge with platelet activating factor (PAF) is able to induce local neurophilia, with a different degree of responsiveness in atopic subjects and in nonatopic subjects. We investigated whether nasal accumulation of neutrophils induced by PAF is accompanied by the release of neutrophil-derived mediators. Methods: Nasal lavages were performed before and after challenge with PAF (500 nmol), lyso-PAF (500 nmol), and saline solution in 10 patients with allergic rhinitis and 10 normal subjects to evaluate changes in neutrophil counts and the release of myeloperoxidase (MPO) and immunoreactive leukotriene B4. Results: PAF caused neutrophilia, which appeared after 30 minutes in atopic subjects and after 3 hours in nonatopic subjects. Furthermore, when compared with saline insufflation, PAF caused a significant release of MPO in the nasal lavage fluids collected 30 minutes, 3 hours, and 24 hours after challenge in atopic subjects and 3 hours after challenge in nonatopic subjects, with higher values in the former than in the latter. Neutrophil counts correlated with MPO levels in the nasal lavages collected after PAF challenge. A lower degree of neutrophilia was found 3 hours after stimulation with lyso-PAF in both groups of subjects, with a marginal release of MPO in atopic subjects only. No significant increase of immunoreactive leukotriene B4 levels in nasal lavages was found after challenge with either PAF or lyso-PAF. Conclusion: These results indicate that PAF-induced neutrophilia in the nose is accompanied by the release of MPO, which appears earlier and is more marked in atopic subjects than in nonatopic subjects

Characterization of T cell subsets in patients with atopic dermatitis using OKT monoclonal antibodies

The distribution of T cell subsets has been studied by means of OKT monoclonal antibodies in 19 children with atopic dermatitis. In these patients a decreased percentage of circulating OKT4+ cells has been observed, while no difference has been found between atopic and normal subjects, regarding the percentages of circulating OKT8+ and OKT11+ cells. An increased OKT4+/OKT8+ ratio has been detected only in three children with a particularly severe and extensive atopic eczem

Evidence of PAF-acether metabolic pathway activation in antigen challenge of upper respiratory airways

Lyso-PAF-acether and PAF-acether (formerly platelet-activating factor) were detected in nasal secretions from patients with hay fever who underwent local antigen challenge. Lyso-PAF release was observed in 12 of 13 patients, with a maximum (p < 0.001) 5 min after stimulation and a progressive decrease during the first hour. PAF was detected in the 5-min postchallenge nasal washings from two of 13 subjects. After HPLC, this mediator was found in four of seven postchallenge nasal washings submitted to this procedure, with a peak 5 min and 10 min after provocation. Histamine analysis revealed a significant (p < 0.001) but time-limited (5 min) release in nasal secretion. The pattern of immunoreactive leukotriene C4 showed a maximal peak (p < 0.01) 5 min after allergen provocation, with raised levels for 20 min. Nasal stimulation with nebulized saline solution or grass pollens in healthy subjects and in patients suffering from allergic rhinitis caused by Dermatophagoides pteronyssinus was followed by no local mediator release. These data indicate that, in addition to histamine and peptide-leukotrienes, lyso-PAF and PAF are released in nasal secretions after local antigen stimulation in patients with hay fever, with a preponderance of lyso-PAF response. On the basis of these results, it is conceivable that these ether-phospholipids may be involved in allergic inflammation of human nasal airways