Venom immunotherapy induces monocyte activation.

BACKGROUND: Venom immunotherapy (VIT) is an efficient treatment of hymenoptera venom allergy. The mechanism of VIT is based on the induction of tolerance of allergen-specific Th2 cells. The mechanisms of this T cell modulation are unknown, and could depend on cytokines produced by other cell types such as interleukin (IL)-12, tumour necrosis factor (TNF)-alpha and IL-10 by monocytes. OBJECTIVE: To assess if VIT modifies the monocyte production of IL-12, TNF-alpha and IL-10 during the 45 first days of treatment. METHODS: Fourteen patients and seven controls were included. Blood samples were taken once in controls and at day (D)1, D30 and D45 of VIT in patients. Monocytes were isolated, cultured with and without lipopolysaccharide (LPS), and the culture supernatant was harvested. IL-10, IL-12 and TNF-alpha were assayed in supernatants by ELISA. RESULTS: Baseline cytokine levels were not statistically different between patients and controls. During treatment, an increase of spontaneous monocyte production of IL-12 and TNF-alpha was observed at D15 and D45. The production of IL-10 increased at D15 and D45 but not significantly. After LPS-stimulation, IL-12, TNF-alpha and IL-10 monocyte production was not modified by VIT. CONCLUSION: VIT induces a monocyte activation characterized by a delayed overproduction of IL-12 and TNF-alpha. These cytokines could be relevant to the inhibition of Th2 cells during VIT. Therefore, VIT-induced tolerance could depend not only on the specific action of venom antigens on T cells, but also on a secondary non-specific action of monocytes.

Cytokines, from atopy to asthma: the Th2 dogma revisited.

Asthma is a spreading condition in Western countries, in most cases in relationship with atopy. Atopy is defined by an individual predisposition to develop allergic diseases in response to environmental allergens. The atopic immune system is characterized by a Th2 deviation determined by genetic and environmental factors. Among these factors, the role of allergen exposure, dietary behavior, air pollution and early exposure to microbes is discussed. In asthma, a Th2 cell activation is evident, but is accompanied by a Tc1 cell activation. These Tc1 cells probably down-regulate Th2 cells, but are also relevant to the bronchial hyperresponsiveness characterizing asthma. We propose that Tc1 activation in asthma could be the link between allergy and bronchial hyperresponsiveness.

[Asthma and allergy]. / Asthme et allergie.

Allergy is routinely taken into account in asthma. The allergic reaction is based on Th2 lymphocytes specific to the allergen, which induce production of E immunoglobulins (IgE) and activation of eosinophils. In atopic asthma, domestic allergens are more often responsible than pollen. They play a part early in the development of the disorder, and subsequently as factors triggering exacerbations. Work-related asthma should always be suspected. History-taking should seek the relevance of allergens in the clinical manifestations, confirmed by skin tests, and if necessary assessment of specific IgE. Provocation tests should be used only diagnosis of work-related asthma. Removal of allergens should be suggested. Specific desensitisation may be indicated in order to decrease high-dosage drug treatment. Rhinologic treatment is part of patient management. Treatments being developed include the use of anti-IgE antibodies, anti-interleukin (IL)-5, soluble IL-4 receptors and recombinant allergens.

[Role of leukotriene inhibitors in the treatment of childhood asthma]. / Place des antileucotriènes dans le traitement de l'asthme de l'enfant.

Leukotriene inhibitors are new pharmacological agents for the treatment of mild to moderate persistent asthma and exercise-induced asthma (EIA). Studies concerning their use in children remain scarce. Available data in the treatment of persistent asthma in children suggest that they could be an alternative to long-acting beta 2-agonists when asthma control cannot be obtained with inhaled steroids alone. Their main advantages are first that they are given orally once daily; second, that they do not induce tachyphylaxis to bronchoprotection against EIA, unlike long-acting beta 2-agonists. Studies specifically conducted in children are necessary to best describe their place in pediatric asthma treatment.

[Role of desensitization in the treatment of respiratory allergies]. / Place de la désensibilisation dans le traitement des allergies respiratoires.

Most authors consider immunotherapy as an efficient and safe treatment for pollen and mite allergic rhinitis. Recent meta-analyses showed that immunotherapy brings a significant benefit to some asthmatic patients depending on the type of allergen used, the severity of the disease, the number of allergenic sensitivities. Nevertheless everybody agrees that pharmacological treatment of asthma and immunotherapy must be complementary when indications of desensitization are given. All precautions to avoid adverse systemic effects or to cure them immediately must be taken. More work is needed as concerning the duration of the treatment, the efficacy of some local allergen administrations, the indications in the young child. The future is based on the use of antigenic peptides and of recombinant allergens.

[Severe air embolism after surgical irrigation with hydrogen peroxide]. / Embolie gazeuse grave après une irrigation chirurgicale à l'eau oxygénée.

BACKGROUND: Hydrogen peroxide is widely used for its antiseptic properties. In certain circumstances, however the risk of air embolism can create a life-threatening situation. CASE REPORT: A 16-year-old adolescent required surgical treatment for femorotibial trauma. During the surgical procedure, cardiac arrest suddenly occurred when hydrogen peroxide was being used to irrigate the wound. A central catheter was inserted and aspiration of air bubbles in the line led to the diagnosis of air embolism. Outcome was unfavorable despite successful resuscitation. A chronic neurovegatative state ensued and the patient died 8 months later. DISCUSSION: Several cases of air embolism have been described due to hydrogen peroxide in surgical, medical and accidental circumstances. Our case emphasizes the potential danger of using hydrogen peroxide in certain situations, including orthopedic surgery. Clinicians should be aware that hydrogen peroxide is not a perfectly safe product.