Can the natural course of allergy and asthma be changed by allergen vaccinations?
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Biomedical subjects
Publications and source records attributed to E Valovirta.
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The Preventive Allergy Treatment Study, the PAT Study, is a European multi-center study. The end-point is to show in what capacity allergen specific subcutaneous immunotherapy can reduce the outcome of asthma in children with allergic rhinoconjunctivitis sensitized to birch and/or timothy pollen. Two hundred and ten children aged from 5 to 13 years were included in the study. Children were randomized to the active treatment group receiving allergen specific immunotherapy with birch and/or timothy pollen allergen extract or to the control group receiving the optimal pharmacotherapy. Immunotherapy was given for the course of three years. Preliminary data show that immunotherapy has been effective, it has been safe and statistically significantly less children in the actively treated group had asthmatic symptoms than children in the control group. Data have not been evaluated from all centers at the moment. The study is a prospective follow-up study, the patients' data will be evaluated next time in the year 2002.
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Circulating immune complexes (CIC) were determined from dog-allergic asthmatic children (n = 35) receiving immunotherapy with dog dander and hair extract. The results from CIC are expressed in SDU (standard deviation units) and presented as follows: pretreatment results (n = 20), rush results (n = 11), mid-schedule results (n = 20), maintenance results (n = 15) and the results of the placebo-treated group (n = 12). The results of the placebo-treated group (n = 12) and those of the untreated atopic (n = 12) and non-atopic (n = 14) were controls. CIC levels were analysed by means of KgB-ELISA (conglutinin binding enzyme linked immunosorbent assay), C1qB-ELISA (C1q-binding enzyme linked immunososrbent assay), RFb-ELISA (rheumatoid factor binding enzyme linked immunosorbent assay) and by PIPA (platelet 125J-labelled staphylococcal protein-A test). The CIC level determined by KgB-ELISA in dog-allergic asthmatic children was higher than that of the atopic controls (P less than 0.05) already before the onset of the hyposensitization. During conventional hyposensitization with dog dander and hair the CIC level remained the same as before treatment. On day 5 of rush hyposensitization the mean level of CIC showed no increase when compared with the pretreatment values. A statistically significant correlation (P less than 0.01) was observed between the dog dander and hair-specific IgG antibodies and the CIC level measured by KgB-ELISA during the maintenance period of conventional immunotherapy. The samples of sera to measure this correlation were collected before the injection of allergen and after 2 weeks of injection during maintenance treatment.(ABSTRACT TRUNCATED AT 250 WORDS)
A double-sandwich enzyme immunoassay (DSEIA) was developed for the detection of human IgG antibodies to dog dander and hair (DH) allergens. Since DH allergens are immunogenic in rabbits, the gamma-globulin fraction of rabbit antiserum to DH (RGG-a-DH; 10 micrograms/ml) was used for coating of polystyrene microtiter plates. Dog allergens (1 microgram/ml of DH extract) were bound to RGG-a-DH. Binding of human IgG Ab to nonimmune RGG (10 micrograms/ml)--used as a background control--was substracted from the DH specific one and nonspecific binding was further eliminated by using 0.5% of normal rabbit serum in the dilution buffer. Sera were diluted 1:10 in this buffer. Specificity of the assay was shown by absorption experiments: protein A, anti-IgE discs (Phadebas PRIST) and dog or birch (e5, t3; Phadebas RAST) allergen discs were used to remove total and allergen specific IgG and IgE, respectively. The results were expressed as net absorbances or as a percentage of a reference serum. A significant correlation (r = 0.65, p less than 0.001) between IgG (DSEIA) and IgE (RAST) antibodies to dog allergens was observed in 40 untreated dog allergic subjects. The DSEIA was found to be more sensitive than conventional ELISA in detecting IgG Ab in 15 asthmatic children during hyposensitization: a significant rise was observed in 14 compared to 12 with ELISA, while no significant increases were observed in the placebo-treated group.
Twenty-seven dog-allergic asthmatic children with no pets in the home were included in the study. The clinical trial was performed as a double-blind study using a commercial standardized aluminum hydroxide-bound dog dander and hair extract or histamine-placebo. The patients were randomized into the active treatment or the placebo group on the basis of the RAST (e5) and the provocation test with aqueous dog dander and hair extract. The good clinical response of immunotherapy with dog dander and hair extract has been reported earlier. The specific immunotherapy resulted in an increase in the serum level of antigen-specific IgG antibodies (P less than .01) and a decrease in the skin sensitivity to dog extract (P less than .001) in the active treatment group when compared with the placebo group. The treatment was well-tolerated. No systemic reactions occurred and local reactions were mild. The results show a good immunologic response with a standardized dog dander and hair extract. There were no major changes in the course of bronchial asthma in either group. After 1 year of immunotherapy the subjects had no symptoms on a dog-exposure of short duration. This must be carefully emphasized when considering the indications for immunotherapy.
Twenty-seven asthmatic children allergic to dog were included in the study. Their allergy to dog was confirmed by positive results from the skin prick, radioallergosorbent and provocation tests. The subjects were randomly assigned to active and placebo groups. Fifteen subjects received immunotherapy with a commercial standardized aluminum hydroxide-bound dog dander extract and 12 subjects received placebo injections containing histamine. After one year's therapy the conjunctival sensitivity to dog dander extract had decreased significantly (p less than 0.001) in the active treatment group compared to the placebo group. The hyposensitization effect was already observable after six to eight months of treatment. The decrease in bronchial sensitivity was less marked than that in conjunctival sensitivity and statistically not significant. Immunotherapy was observed to be safe and effective. No systemic adverse reactions occurred and local reactions were mild.
The commercial cat and dog allergen extracts are traditionally prepared from pelt, fur or dander. However, there is increased evidence of the allergenicity of saliva and urine of the animals. We have investigated 25 asthmatic children with a positive cat and/or dog RAST result. All 20 subjects with a positive cat RAST gave a positive skin prick test result to cat saliva, cat urine and cat hair. Analogously, all 20 subjects with a positive dog RAST had a positive skin reaction to dog saliva, urine and dander. In RAST inhibition experiments with dog and cat allergen discs, dog saliva appeared to be at least as potent as a commercial dog dander and hair extract, while cat saliva was less potent than the respective commercial extract. Both dog and cat salivas were clearly more potent than the respective urine. Significant cross-reactivity was observed between cat hair and dog dander in the RAST inhibition, whereas saliva and urine were shown to be more species-specific. An experimental dog dander preparation had about the same specificity as, and even higher allergenic activity than, that of dog saliva or urine. Our results suggest that saliva actually may be the best source of cat and dog allergen preparations. The importance of urine warrants further investigation.
In order to test the possible differences in the clinical effects between benzodiazepines and barbiturates, 5 mg of diazepam and 60 mg of pentobarbital were used in a double-blind study as rectal premedication in 75 small children before major surgery. There were no significant differences between the two groups in the six parameters tested (demeanour in the anaesthetic room, preoperative emetic effect, response to venepuncture, degree of salivary suppression, postoperative state in the recovery room, postoperative emetic effect). The concentrations of pentobarbital and diazepam (and its 3 active metabolites) in the plasma were determined by gas chromatography and correlated with the clinical effects. No significant correlation was found between the total active benzodiazepine concentrations and the clinical effects of rectal diazepam. In contrast to diazepam, a weak but significantly positive correlation between the plasma concentrations of pentobarbital and the total score was found. Similarly, the plasma level of pentobarbital and the response to venepuncture and the degree of salivary secretion were in correlation with each other. In the plasma concentrations of both pentobarbital and total benzodiazepines, a wide interindividual variation was observed, indicating irregular rectal drug absorption.
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