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Notes: A double-antibody radioimmunoassay for measurement of grass pollen antigen-specific IgG in serum is described. Grass pollen antigens were used to show a correlation between the results obtained by this method and those obtained by measuring blocking antibodies by inhibition of antigen-induced leukocyte histamine release. The new technique described is convenient, sensitive, specific and reproducible and can be recommended for clinical use.

Notes: Preseasonal hyposensitization stimulated an intercorrelated increase in both serum-specific IgE and allergen-specific IgG. Subsequent perennial treatment depressed the stimulated IgE response and the basophil cell sensitivity, whereas the allergen-specific IgE response showed further increase and persisted at a high level. Nasal IgE response was stimulated from the second pollen season and subsequently became depressed. One year after the end of hyposensitization the allergen-specific IgE response had fallen by 25–50%.

Notes: Short-lived occupational skin symptoms of irritant or urticarial nature were commonly reported among 253 attendants in a clinical study on occupational dermatitis in Danish gardeners and greenhouse workers. Aimed prick or scratch-patch testing for immediate skin and mucosal symptoms was performed in 105 persons with plants as is. 35 persons (33%) had at least 1 positive reaction and a family history of, or personal, atopy was significantly more prevalent among these compared to attendants with negative reactions. Positive histamine release tests made immunologic etiology probable in Schlumbergera cacti, Stephanotis floribunda, Euphorbia pulcherrima and Gerbera reactions. Other new species implicated in immediate-type reactions included Ficus pumila, Gardenia jasminoides, Hibiscus rosa-sinensis, Campanula, Columnea, Epipremnum aureum, Pelargonium and Primula vulgaris. Because of the high prevalence of short-lived skin symptoms and because contact urticaria may present itself as a dermatitis, it is recommended that one supplement patch tests with tests for immediate reactions.

Notes: The effect of treatment with astemizole (Hismanal®) on symptoms elicited by ingestion of hazelnuts in birch pollen-allergic patients (the oral allergy syndrome) was investigated. Thirty patients with a well-documented allergy to silver birch, experiencing symptoms when ingesting hazelnuts, were included in the study. All had a positive skin prick test (SPT) to birch, whereas 29 and 27, respectively, showed a positive RAST and basophil histamine release test (HR) to birch. In contrast, only 15 patients had a positive SPT to hazelnut, 13 had a positive RAST, whereas 24 had a positive HR. Alter two oral provocations with hazelnuts the patients were randomized to receive either 10 mg of astemizole or placebo daily for 2 weeks in a double blind protocol followed by two oral provocations. Treatment with astemizole significantly reduced the symptoms compared with placebo (P= 0.004); however, without completely abolishing the symptoms.

Notes: The aim was to compare IgE and IgG4, RAST-inhibition assay (RI), monoclonal antibody ELISA (Mab-ELISA), counter current immuno electrophoresis (CCIE) and histamine release from basophil leukocytes (HR) for allegen quantification with special reference to aeroallergen detection. As components of indoor acroallergens, cat, dog, and Derm. pter. allergen extracts were selected for the experiments. To evaluate unspecific interference, these allergens were compared mutually and with Cladosporium herbarum. Allergen extracts in varying dilutions were mixed with crushed glass fibre filter materials, eluted, recovered by centrifugation, and allergen concentration quantified by the assays. Equal sensitivity was found for both IgE- and IgG4-RI assaying eat allergen (in the range 5 − 50 SQ-U/ml) and dog allergen (in the range 102− 103 SQ-U/ml). The IgG4-RI assaying Derm. pter, was more sensitive (50 SQ-U/ml) than IgE-RI (2*103 SQ-U/ml). The ranges of allergen detection limits for the Mab-ELISA were equal for cat and Derm. pter. (10 – 102 SQ-U/ml). The range of allergen detection limits for CCIE, assaying dog were 104− 105 SQ-U/ml. The ranges of allergen detection limits for HR were equal for eat and Derm. pter. (10 – 102 SQ-U/ml), and 102− 103 SQ-U/ML for dog. Because of cross-reactivity, a minor degree of interference was observed in the IgE-RI and the HR test for the highest concentration of cat and dog allergens.

Notes: The purpose of this study was to evaluate the application of a microdialysis technique for measurement of interstitial histamine levels in intact human skin. Three allergic subjects were investigated. Single dialysis fibers were glued to nylon tubings and inserted in forearm skin by means of a fine cannula. Dialysis fibers were inserted in triplicate and perfused with isotonic saline at a rate of 3 μl/min. After a period of 2 h a 60-μl base-line period was established. Then the patients were skin prick tested (SPT) with allergen in duplicate and a single saline control. Dialysate was collected in consecutive 30 μl fractions. Histamine concentration in the dialysate was analyzed with a glass fiber fluorescence assay. Median base-line histamine level was 4 (range 4–7) ng/ml. Following allergen SPT, dialysate histamine concentration increased to 81 ng/ml (74–128), with maximum values 10–20 min after SPT. Intraindividual coefficient of variation on peak histamine levels was 18.9%. No histamine increase was seen following saline SPT. We consider microdialysis to be a valuable method for assessment of allergic mechanisms in intact human skin.

Notes: Forty-six adult asthmatics allergic to D. pteronyssinus (Dp) participated in a 2-year study. Thirty-one underwent hyposensitization (HS-group). Fifteen were treated with Dp-extract (Dp-group), and 16 with a similar extract modified by monomethoxypolyethylene glycol with reduced allergenicity (mPEG-Dp-group). Fifteen patients served as controls. Dp-specific antibodies and histamine release from blood basophils were determined and compared with Dp-sensitivity in lungs and skin. In addition, IgG and IgE against the major allergen Der p I were followed in a subgroup. Dp-specific IgG, IgG., and IgG4 increased significantly in both HS-treated groups after 1 and 2 years (median; 2.5- to 11.6-fold). IgG4 was not induced if maintenance dose during the first year was less than 20,000 BU. Median skin sensitivity decreased 4.4- to 8.2-fold after 1 year and 7.4- to 21.4-fold after 2 years. Der p I specific IgG response was unrelated to the occurrence or change in IgE with the same specificity. The mPEG-Dp-extract tended to have less effect on skin sensitivity and immunological parameters, differences reaching statistical significance for skin sensitivity only. In the HS-group, the decrease in bronchial sensitivity was significantly correlated to a decrease in IgE (r = 0.36), IgG1/IgG4 (r = 0.49), Dp-specific histamine release (r = 0.58), and to an increase in Dp-specific IgG, (r =−0.36) and IgG4/IgE (r =−0.48). In patients improving clinically. Dp-specific IgG4/IgE increased, and median Dp-specific IgE was reduced to 80 % compared with an increase to 150–160% seen in the unchanged or deteriorated group (P 〈 0.05). Findings indicate an improvement of effect, if the allergen dose is sufficient to reduce specific IgE and/or induce an IgG and especially IgG4 response.

Notes: The in vitro histamine release response of human intestinal mast cells and basophils challenged with anti-IgE, Concanavalin A, ionophore A23187 and food extracts was compared with skin prick test, RAST analysis and open food challenge. It was not possible to perform food challenge in all patients; however, seven children underwent open food challenge and in five the clinical diagnosis of “true” food allergy was confirmed. The intestinal mast cells were pooled from enzymatically dispersed duodenal biopsies obtained by duodenoscopy from 15 selected children suspected of food allergy, and five age-matched controls. In nine of 10 patients classified as “food allergic” intestinal mast cells released histamine to various food extracts in a dose-dependent fashion. From the mast cells of the nine food-allergic patients compared with non-allergics, the anti-IgE mediated mast cell histamine release was increased. Additionally, at 1000 U/ml anti-IgE the mast cell histamine release was increased compared with their corresponding basophils. However, in non-allergic subjects the histamine release of basophils was increased compared with their corresponding mast cells. Histamine release from basophils was positively correlated to the test scores of the RAST analysis, skin prick test, and food challenge. No apparent correlation between tests scores obtained from histamine release of intestinal mast cell and the other tests was demonstrated, except in children with diarrhoea as only symptom. However, the study gives evidence that duodenal mast cells actually are sensitized with specific IgE and thus may play a pathophysiological role in food hypersensitivity. In addition, the study shows that the ability of different stimuli, including food extracts, to trigger basophil histamine release does not correlate with their potency to induce histamine release from mast cells.

Notes: The interrelation of in vitro IgE-mediated parameters, i.e. serum-specific IgE (RAST), basophil cell-bound specific IgE, and histamine release from basophil leucocytes was investigated in a 1-year placebo-controlled, double-blind Cladosporium immunotherapy study involving 22 adult asthmatics. The intense and early burst (within 6 weeks of immunotherapy) of serum-specific IgE did not result in a corresponding increased binding of specific IgE molecules to basophils. Cell-bound IgE increased in the Cladosporium season in both groups at the same time as serum levels of specific IgE declined in the Cladosporium group. In the placebo group histamine release from circulating basophils paralleled changes in basophil-bound IgE. In Cladosporium-treated patients, histamine release cell sensitivity after a lag phase (during immunotherapy dose-increase) declined two log steps, i.e. the cells became less responding in spite of a significant increase in cell-bound IgE. To further evaluate the sensitizing capacity of circulating specific IgE, passive sensitization studies were performed using basophils from a single donor. Although sera taken at the maximal IgE-response showed an enhanced capacity of passive sensitization, the ratio between RAST and passive sensitization capacity increased significantly in Cladosporium-treated patients, implying a less than expected sensitization capacity of immunotherapy-induced specific IgE. The lack of active binding of IgE to basophils might be explained by a reduced Fc-affinity of immunotherapy-induced IgE in contrast to the Cladosporium seasonally induced IgE. Regarding the decrease in histamine release in Cladosporium-treated patients in spite of an increased amount of cell-bound specific IgE, immunotherapy may initiate a decrease in mediator releasibility which is not caused by a reduction in the number of Fc-receptors but rather some yet unknown subcellular mechanisms regulating the histamine release. The described changes in IgE-mediated parameters do not seem to be caused by interference with either specific IgG, or IgG4. Changes in histamine release in the Cladosporium, season were the only IgE-mediated parameter significantly related to the graded clinical efficacy of immunotherapy.

Notes: The inhibitory capacity of calcium antagonists on basophil histamine release was examined in allergic patients and in controls. All dihydropyridines tested (nifedipine, nimodipine, nitrendipine, nicardipine, felodipine) dose-dependently inhibited anti-IgE- and A23187-induced release with an order of potency of felodipine 〉 nicardipine 〉 nifedipine = nimodipine = nitrendipine. Only the inhibition induced by felodipine and nicardipine on anti-IgE-induced release could be counteracted by increasing extracellular calcium. Diltiazem, not belonging to the dihydropyridines, was a weak inhibitor. A combination of felodipine and verapamil in low concentrations exerted a synergistic inhibitory effect on histamine release, whereas this was not the case with other combinations of antagonists. The results suggest differences in the mode of action of the 1.4-dihydropyridines. This might be of significance in the search for calcium antagonists suitable in the treatment of allergic diseases.