Cofactors in food anaphylaxis in adults.

Around 25% to 50% of food-induced allergic reactions in adults cause anaphylaxis, and epidemiologic evidence suggests that food is the most common cause of anaphylaxis. Reaction severity is unpredictable, and patients will often experience reactions of variable severity, even to an identical exposure (both dose and allergen). A common explanation for this phenomenon has been the impact of "cofactors"-factors that might contribute to reaction severity independent of the allergen exposure. Cofactors can influence reaction severity in 2 ways: either by reducing the reaction threshold (ie, the dose needed to trigger any symptoms) so that patients have no symptoms in the absence of the cofactor and only react with the cofactor present, or by increasing reaction severity such that individuals have only mild symptoms in the absence of the cofactor, but a more severe reaction when the cofactor is present. Indeed, the same patient may have reactions with different cofactors or even need more than one cofactor to develop a severe reaction. Cofactors reportedly play a role in approximately 30% of anaphylaxis reactions in adults. Exercise, nonsteroidal, anti-inflammatory drugs, alcohol, and sleep deprivation are the most frequent cofactors reported. Routine evaluation of the possible involvement of cofactors is essential in managing patients with food anaphylaxis: in patients with a suggestive history but a negative oral food challenge, cofactors should be taken into account to provide appropriate advice to reduce the risk of future anaphylaxis.

Performance of basophil activation test and specific IgG4 as diagnostic tools in nonspecific lipid transfer protein allergy: Antwerp-Barcelona comparison.

BACKGROUND: Recent studies show that nsLTP sensitization is not limited to the Mediterranean basin and can present diverse clinical phenotypes. It remains challenging to predict clinical outcome when specific IgE antibodies (sIgE) to nsLTPs are present. This study compares both clinical and in vitro allergy characteristics but also diagnostic performance of a basophil activation test (BAT) and sIgG4 in nsLTP-sensitized patients from Antwerp (ANT, Belgium) and Barcelona (BCN, Spain). METHODS: Adult subjects with positive sIgE rPru p 3 and/or rMal d 3 ≥ 0.10 kUA /L (n = 182) and healthy controls (n = 37) were included. NsLTP-sensitized individuals were stratified according to clinical symptoms with peach/apple, respectively. BAT rPru p 3 and rMal d 3 were performed and sIgG4 antibodies to both components quantified. RESULTS: In BCN, only ratios of sIgG4/sIgE rMal d 3 and BAT rMal d 3 (0.001 µg/mL) can identify clinically relevant Mal d 3 sensitization (sensitivity of 60%-63% and a specificity of 75%-67%, respectively). In ANT, only the sIgE/total IgE rPru p 3 ratio shows added value (sensitivity 60% and specificity 83%). Finally, it appears that symptomatic patients in BCN are more sensitive to lower allergen concentrations compared to ANT. In addition, it was shown that ANT patients were more often sensitized to pollen and that specific pollen sources differed between regions. CONCLUSIONS: NsLTP-related allergy profiles and diagnostic performance differ significantly between regions and are component-specific, which makes extrapolation of data difficult to do. In addition, it seems that basophil sensitivity might show geographical differences. Additional research is needed to confirm these findings.

Platelet-Activating Factor (PAF) in Allergic Rhinitis: Clinical and Therapeutic Implications.

Platelet-activating factor (PAF) is a lipid mediator involved in several allergic reactions. It is released from multiple cells of the immune system, such as eosinophils, neutrophils, and mast cells, and also exerts its effect on most of them upon specific binding to its receptor, becoming a pleiotropic mediator. PAF is considered a potential relevant mediator in allergic rhinitis, with a key role in nasal congestion and rhinorrhoea due to its effect on vascular permeability. Interestingly, despite its potential relevance as a therapeutic target, no specific PAF inhibitors have been studied in humans. However, rupatadine, a second-generation antihistamine with dual antihistamine and anti-PAF effects has shown promising results by both blocking nasal symptoms and inhibiting mast cell activation induced by PAF, in comparison to antihistamine receptor drugs. In conclusion, the inhibition of PAF may be an interesting approach in the treatment of allergic rhinitis as part of a global strategy directed at blocking as many relevant inflammatory mediators as possible.

Allergic respiratory disease (ARD), setting forth the basics: proposals of an expert consensus report.

BACKGROUND: The variability of symptoms observed in patients with respiratory allergy often hampers classification based on the criteria proposed in guidelines on rhinitis and asthma. OBJECTIVES: We assessed specific aspects of allergic respiratory disease (ARD) that are not explicitly addressed in the guidelines in order to issue specific recommendations and thus optimize clinical practice. METHODS: Using the Delphi technique, 40 Spanish allergists were surveyed to reach consensus on 71 items related to ARD. RESULTS: Consensus was achieved for 95.7% of the items. These included the following: the clinical manifestations of ARD are heterogeneous and individual airborne allergens can be related to specific clinical profiles; the optimal approach in patients with ARD is based on the global assessment of rhinoconjunctivitis and asthma; aeroallergens are largely responsible for the clinical features and severity of the disease; and clinical expression is associated with the period of environmental exposure to the allergen. Pharmacological treatment of ARD is often based on the intensity of symptoms recorded during previous allergen exposures and cannot always be administered following a step-up approach, as recommended in clinical practice guidelines. Allergen immunotherapy (AIT) is the only option for overall treatment of respiratory symptoms using an etiological approach. AIT can modify the prognosis of ARD and should therefore be considered a valuable first-line treatment. CONCLUSIONS: The present study highlights gaps in current asthma and rhinitis guidelines and addresses specific aspects of ARD, such as global assessment of both asthma and rhinitis or the specific role of variable allergen exposure in the clinical expression of the disease.

[Clinical relevance of distal airway involvement in asthma]. / Importancia clínica de la afectación de la vía aérea pequeña en el asma.

Asthma continues to be a global health problem, despite advances in diagnostic techniques and treatment. The inflammatory nature of asthma is currently indisputable, as is the involvement of the entire respiratory tree, both the proximal and most distal airways, which has been demonstrated in multiple studies. The development of the therapeutic arsenal, with more potent drugs and improved inhalation devices, has allowed a certain control to be maintained over the inflammatory process, although the inability to reach the most distal points of the airways has posed a stumbling block that seems difficult to overcome. However, the available information on the real role of distal airway involvement in asthma remains very scarce. Physiopathological evidence shows that, in addition to the large airways, the small or distal airways (those with a diameter of less than 2 mm) substantially contribute to the severity of asthma. Several studies have shown that the inflammatory process seems to be more intense in this area. This finding has been related to nocturnal asthma and an increase in glucocorticoid receptor-beta-expressing cells, associated with corticosteroid-resistant asthma and fatal asthma. Equally, small airway involvement seems to be a highly important factor in asthma in the pediatric age group.