Toll-like receptors (TLRs) act as receptors for numerous stimuli of immune cells, including bacterial cell wall constituents (lipopolysaccharide [LPS] from Gram-negative bacteria and lipopeptides from Gram-positive species), plasma proteins and extracellular matrix breakdown products. TLR2 and TLR4 bind lipopeptide and LPS respectively, mediating responses of alveolar macrophages and other immune cells to bacterial infection in the lungs. Exposure of lungs to LPS leads to pro-inflammatory responses of a number of cell types, including airway smooth muscle, which secretes a number of cytokines involved in leucocyte recruitment and the Th2 polarization of immune responses. Human airway smooth muscle cells were cultured with LPS in the absence and presence of peripheral blood mononuclear cells to determine direct and leucocyte-dependent TLR-mediated responses. (more…)

Allergic rhinitis and asthma are common comorbidities. Like asthma, the presence of a genetic component in allergic rhinitis has been well established. To identify genetic linkage regions unique to allergic rhinitis, as well as those shared by allergic rhinitis and asthma, a genome screen study was conducted. A total of 295 families in the French Epidemiological Study on the Genetics and Environment of Asthma (EGEA) containing 1317 subjects were genotyped for 396 microsatellite markers. The families included had two siblings with DNA available and at least one asthmatic subject. Three definitions of allergic rhinitis were used, two binary and one categorical. To investigate linkages specific to allergic rhinitis (without asthma), linkage analyses were also conducted in 185 families with at most one asthmatic sib. (more…)

For most patients, asthma is not controlled as defined by guidelines; whether this is achievable has not been prospectively studied. It is also not known whether combination LABA ICS therapy is more likely to achieve this than an increased dose of ICS.

Control was achieved more rapidly and at a lower inhaled corticosteroid asthma dose with salmeterol/fluticasone than with fluticasone. This study confirms that the goal of guideline derived asthma control was achieved in most of the patients. (more…)

Adjusting the inhaled glucocorticoid dose based on indices of airway inflammation has been proposed as a means of achieving more effective control of asthma than the conventional approach of adjusting steroid dose based on symptoms, lung function and rescue medication use. In a single-blind, placebo-controlled trial, 97 asthmatic patients received fluticasone doses adjusted on the basis either of conventional guidelines or of exhaled nitric oxide fraction (FE NO ). (more…)

Asthma is a complex syndrome rather than a single disease entity. Different phenotypes with varying prognosis and determinants have been described, particularly over childhood years 2 and will be discussed in detail in the following. For example, transient early wheezing is characterized by the occurrence of wheezing in infants up to the age of 2 to 3 years which disappears thereafter. The main predictor of these wheezing illnesses is premorbid reduced lung function before the manifestation of any wheeze. These decrements in pulmonary function are in part determined by passive smoke exposure in utero 4 and result in symptoms of airway obstruction when infants get infected with respiratory viruses. (more…)

The protective effect of breast-feeding on asthma and allergy has been debated for more than 60 years without any hope of a consensus. A major problem is the lack of randomized controlled trials. However, breast-feeding has a number of other benefits and should be recommended irrespective of any effect on asthma or allergy. This is why randomized trials are not considered ethical. Thus, we have to rely on observational studies, which have produced conflicting results. Mothers who do or do not breastfeed differ in several environmental exposures, including socio-economic class, smoking and area of living, which influence indoor and outdoor exposure to pollutants. Despite statistical adjustment for these confounding factors, the evidence is never as robust as it would be with an randomized controlled trial. (more…)

By definition, allergy is a condition where a person has hypersensitivity to an environmental, drug, or food antigen (allergen) caused by an altered or unusual immune system reaction to the antigen.

Allergenic foods can impact the lungs when an allergic reaction individual inhales food particles that may have been released when the food was cooked or that were dispersed in aerosol form. Allergy to the allergens in cooked food has been reported by highly allergic patients who were exposed to their allergenic foods (say, fish, shellfish, or eggs) in an enclosed area (for example, a restaurant dining room) or during meal preparation. Most cases of asthma triggered by aerosolized food allergens involve adults engaged in specific occupations that regularly expose them to the allergens. In contrast, most cases of asthma in children are triggered when the allergen is eaten, not inhaled.

Many experts believe that if a baby can be protected from becoming sensitized to the most highly allergenic foods when their healthy immune system and the digestive tract are in the most vulnerable stage for allergy to develop, the incidence of lifelong food allergy and potentially life-threatening anaphylactic reactions to foods will be reduced and hopefully entirely prevented. When a baby has been identified to be at risk for developing allergy, measures to reduce allergic sensitization might be implemented at birth and the problems associated with future food allergy may be significantly reduced. However, as we shall see in later discussions, experts disagree on the best way to avoid this early allergic sensitization.

The reaction of asthmatics to these chemical compounds is not an allergy, but is more correctly described as allergy intolerance because the initial response is not a triggering of the immune system. The process involves an increase in the level of the inflammatory mediators that are responsible for the bronchospasm of asthma. These mediators include histamine and leukotrienes. They are released during the reaction to an allergen, and cause the muscular contractions that result in the difficulty in breathing and wheezing that are typical of asthma. By inhibiting (or turning off) other types of mediators, the chemicals in the food additives cause an increase in the level of antihistamine and leukotrienes. This results in increased bronchospasm, and a definite worsening of the asthma symptoms.

Oral allergy syndrome is an allergic reaction to food that is confined to the oral cavity (i.e., to the lips, and around the lips, roof of the mouth, tongue, hard and soft palate, and uvula) and adjacent structures. It differs from other food allergy in that its symptoms do not appear in any other location in the body, and always accompany respiratory allergy to inhaled allergens of plants, particularly plant pollens. Of course, symptoms in the mouth, throat, and upper respiratory tract can be part of a generalized reaction to foods, but in this case they are more accurately described as oral allergy symptoms. The term oral allergy syndrome applies specifically to pollen allergy (pollinosis) accompanied by reactions to certain raw foods when they are in direct contact with oral tissues. Individuals with Oral allergy syndrome typically have hay fever symptoms caused by allergies to trees, grasses, and weeds. They experience irritation in the mouth (lips, tongue, roof of the mouth) and sometimes the throat after eating specific types of raw fruits, vegetables, and sometimes nuts.

It is very common in asthmatic children where overprotective parents prevent a normal level of exercise to their kids. However, a controlled sport appropriate to the course of their disease is very healthy.

Asthma is an inflammatory disease of the airways characterized by variable bronchial obstruction and reversible, either spontaneously or with treatment, (more…)

Definitions of anaphylaxis vary considerably, impeding the comparison of different clinical studies. Different definitions of anaphylaxis have been developed as clinical descriptions of severe allergic reactions, different authors emphasizing different symptoms.

The author aimed to develop a simple clinical grading system and definition for anaphylaxis using clinical data. He retrospectively analyzed 1149 case records (median age 29 years) with systemic allergic reactions (30% venom allergy, 22% iatrogenic allergy, 18% food allergy) from an emergency department in Australia. (more…)

A cross-sectional, descriptive, questionnaire-based survey was conducted in schools in Toulouse, France, to determine the prevalence of food allergies among children in school. The first goal of the survey was to estimate the prevalence of food allergies. The second goal was to determine the main characteristics of the allergies. The questionnaires (3500) were distributed in 150 classes in eight schools. The return rate was 77.6% (2716). (more…)