Adverse reactions to food. European Academy of Allergology and Clinical Immunology Subcommittee.
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Child↗
Biomedical subjects
C Bruijnzeel-Koomen
Publications and source records attributed to C Bruijnzeel-Koomen.
Skin eosinophilia in patients with allergic and nonallergic asthma and atopic dermatitis.
Skin eosinophilia induced by grass pollen or platelet-activating factor (PAF) was investigated in patients with allergic and nonallergic asthma and atopic dermatitis (AD) and in normal control subjects. Intracutaneous injection of PAF resulted in positive immediate skin reactions in all tested individuals. Since most of the patients with allergic and nonallergic asthma and eczema under investigation were characterized by a peripheral blood eosinophilia, we investigated whether PAF should be capable of mobilizing blood eosinophils to the skin of patients with nonallergic asthma and AD using the Rebuck skin window technique. Our results demonstrated that, in allergic individuals, allergen induced a much stronger skin eosinophilia than PAF and in a larger percentage of the patients (77% versus 45%). There was no correlation between skin eosinophilia induced by PAF and the occurrence of late skin reactions to allergen. Furthermore, the PAF-induced and the allergen-induced skin eosinophilia differed histologically. In nonallergic individuals, neither allergen nor PAF was capable of mobilizing eosinophils in the skin window, in spite of the presence of peripheral blood eosinophilia. Our results indicate that the allergen- and PAF-induced skin eosinophilia are different and that in patients with nonallergic asthma and AD, another chemoattractant than PAF must be responsible for eosinophil mobilization in the target organ.
Adult↗
[Langerhans cells in the physiopathology of atopic dermatitis].
INTRODUCTION. Atopic dermatitis (AD), allergic rhino-conjunctivities and allergic asthma constitute the classical triad of atopic diathesis attended, in many cases, by high serum IgE levels. While the pathophysiology of IgE-mediated allergic respiratory diseases is now better understood, the pathophysiological significance of atopic phenomena in the genesis and control of AD is still far from being clear. Numerous clinical and laboratory data point to a pathophysiological relation between IgE-mediated reactions and AD, but no one yet knows by which mechanism this interaction takes place. Some recent studies suggest that Langerhans cells might well be the missing link. THE LANGERHANS CELLS. Langerhans cells (LC) are dendritic epidermal cells originating in the bone marrow and supposedly belonging to the monocyte lineage. Their circulating precursors, the mechanism of their migration into the epidermis and their relationship with other dendritic cells, such as the interdigitating follicular cells, are controverted. LC express numerous surface markers, such as class I and II HLA, CD1a, CD4 and receptors for complement and IgE Fc fragments. Under normal conditions, LC do not express IgE receptors. Ultrastructurally, LC are characterized by the presence of Birbeck granules in their cytoplasm. Among the presumed functions of LC in the skin, the best documented is the presentation of antigens to T lymphocytes in allergic contact dermatitis. LANGERHANS CELLS IN ATOPIC DERMATITIS. Quantitative studies. Modern immunohistological methods based on the reactivity of monoclonal anti-CD1a antibodies have given results that are sometimes conflicting due to differences in the quantification techniques utilized. However, morphometric enumeration of LC on cryostat sections have shown that their number is about the same in AD and in normal skin. PRESENCE OF IgE BEARING LANGERHANS CELLS IN ATOPIC DERMATITIS. The presence of IgE molecules on the LC surface has been demonstrated in subjects with AD. It must be noted that in atopic subjects IgE bearing Lc are only found in patients with high serum IgE levels. They are absent in asthma patients without eczema, irrespective of their serum IgE levels. Daily applications of corticosteroids on AD lesions result in a decrease of anti-IgE markers on LC after one week and in their complete disappearance after 2 weeks. IN ATOPIC DERMATITIS LANGERHANS CELLS EXPRESS A RECEPTOR SPECIFIC TO Fc FRAGMENTS OF IgE. The exact nature of the receptor for IgE expressed in situ in AD patients is still conjectural. Some authors have been able to demonstrate that the binding of IgE molecules by LC isolated from the skin of atopic patients is inhibited by a monoclonal antibody directed against the low affinity receptor (Fc epsilon R2) of eosinophils and macrophages. This strongly suggests that certain factors induce the expression by LC of an Fc epsilon R2 receptor. IN VITRO INDUCTION OF IgE RECEPTORS ON NORMAL LANGERHANS CELLS...
Dermatitis, Atopic↗
Delayed type hypersensitivity in atopic dermatitis.
Three different aspects of delayed type hypersensitivity in atopic dermatitis (A.D.) were studied. (a) Intradermal testing demonstrated that positive reactions to bacterial vaccines were distinctly lower in patients with A.D. (b) Patch testing in patients with A.D. compared to tests in patients with anal eczema showed a striking difference in results concerning the substances to which positive reactions were found. (c) Patients with A.D. (n = 18), atopics without A.D. (n = 10), patients with contact dermatitis (n = 10), and normal controls (n = 10), were patch tested with various human dander (H.D.) fractions after stripping the stratum corneum with skin tape. Only patients with A.D. showed positive reactions, the maximum response being at 24-48 hours. There was no difference in reaction pattern between partially purified H.D. subfractions. Histopathological examination revealed an eczema-reaction. Patch testing within the same patient groups with purified house dust mite allergen P1 demonstrated similar results. Although this finding argues against a specific role of H.D. allergen in A.D. it may at least be concluded that H.D. preparations have the capacity to provoke immediate as well as delayed type skin reactions.
Adolescent↗