Fred Björkstén

Dependence of immediate hypersensitivity in the adolescent period on factors encountered in infancy.

708 unselected adolescents 15–17 years old were studied. They were physically examined, interviewed and skin prick tested with 12 common allergens. Questionnaires were distributed to the adolescents and their parents to investigate past and present symptoms and environmental influences. Emphasis was on the first year of life. Exposition to allergens (pollens and cat epithelium) during the first 6 months of life, eczema during the First year of life, and atopic heredity were found to be major risk factors in die development of positive skin tests and respiratory allergy apparent in the teenage period. Infections and wheezing during the first year of life were also risk factors, but less important.

Serum immunoglobulin E in atopic and non-atopic children aged 6 months to 5 years. A follow-up study.

ABSTRACT. In order to obtain serum IgE reference values for small children we measured the total serum IgE concentration at the ages of 6 months, 1, 3, and 5 years in 66 healthy, non‐atopic children who were followed from birth to 5 years of age. From this reference group we had excluded children with symptoms or signs of atopy during the follow‐up period, as well as children with blood or nasal smear eosinophilia or positive skin prick tests. We also studied serum IgE levels in groups of children having latent atopy, symptomatic atopy, or severe atopic disease. We suggest that in the definition of reference values the upper limit of normal should be replaced by a zone of uncertainty, lying between the 95th and 97.5th percentiles. Serum IgE is a useful test with high specificity but low sensitivity in the differentiation between atopy and non‐atopy. Thus high levels suggest atopy, while normal or low values yield little information. A normal serum IgE level does not necessarily exclude atopic disease.

Do infections in infancy affect sensitization to airborne allergens and development of atopic disease? A retrospective study of seven-year-old children.

We studied 145 children aged 7 years, who had been at day‐care centers for at least 3 months during the 2 first years of their lives. The group was compared with a matched population of 145 children cared for at home. Of the 290 children, 212 participated in all phases of the study, which included a questionnaire to parents, skin prick tests with seven allergens, and a clinical examination. Day‐care‐center children had twice as much otitis media in infancy as “home” children (P < 0.001), and they also tended to have more other infections. On the other hand, day‐care‐center children did not have more eczema in infancy, more cumulated atopic disease by the age of seven, or more positive skin tests than home children. When the groups were combined, an increased prevalence of cumulated atopic disease and positive skin tests was found in children with infections in infancy. We conclude that under the conditions of this study infections in infancy did not facilitate the development of hypersensitivity to allergens and atopic disease. The linked tendencies to develop infections and atopy could depend on some third factor.

Spice allergy: results of skin prick tests and RAST with spice extracts

Skin prick tests (SPT) with freeze‐dried spices and 5% (w/v) spice extracts were performed on 50 patients with 2 + or stronger SPT reactions to spices per se, and RAST were performed on 10 of them. Freeze‐dried extracts produced mostly equal or stronger SPT reactions than corresponding whole spices, but 5 % (w/v) extracts produced weaker reactions and also remained totally negative in some patients. Positive RAST results were seen in all 10 patients tested. The correlation between the RAST and SPT results was good for mustard and paprika, but poor for cayenne, coriander, caraway and white pepper. Five patients with positive SPT and RAST for spices contracted rhinitis from powdered spices in their working environments, and one patient suffered from gastrointestinal pains caused by spiced food. The others had noticed no clinical symptoms caused by spices. The present results thus indicate that both SPT and RAST should include purified spice extracts.

Eosinophil cationic protein in induced sputum as a marker of inflammation in asthmatic children

We evaluated the usefulness of eosinophil cationic protein (ECP) in induced sputum and in serum as markers of asthmatic inflammation in children. We measured ECP in serum and in total indticed sputum samples from 14 children (7‐11 years) with newly detected asthma before and after treatment, and from ten healthy non atopic controls of the same age. The patients inhaled budesonide, 800 μg/m2/day for the first month and 400 μg/m2/day for the next 5 months, both divided into two doses, and nedocromil, 4 mg three times daily for the following 6 months. In both sputum and serum, ECP levels were higher in the patients than in the controls, but the difference was more distinct in sputum. Significant clinical improvement during the treatment was accompanied by a decrease in sputum ECP. whereas serum ECP did not change. The results suggest that induced sputum is useful as a non invasive source material for evaluating asthmatic inflammation in children, total sputum ECP being more sensitive than serum ECP for diagnosing and monitoring asthma.

Assay of the biologic activity of allergen skin test preparations

We studied the biologic activity of allergen preparations using a method involving skin prick tests in humans and the use of HEP (histamine equivalent prick) units. Results were found to be dependent on the population groups used in assays. If populations are not carefully standardized, results may vary by 1 power of 10. Accuracy can also be improved by the use of suitable allergen standard reference preparations, but such were not available to us. Confidence ranges for the biologic activities were relatively wide and varied with the allergen preparation and the population group. Typically, the 95% confidence range included values from one-fifth to five times the estimated HEP value when the number of subjects in the assay was 30 to 50 persons. When the preparations representing the same source material (e.g., timothy pollen) were assayed simultaneously in one population group of this size, a twofold or larger difference in HEP values generally proved significant. An examination of 43 commercial products showed that allergen preparations with biologic activities declared in HEP units had a more uniform biologic activity than those assayed with traditional methods and units (PNU/ml or weight/volume).

A simplified Boyden chamber assay for neutrophil chemotaxis based on quantitation of myeloperoxidase

Cell locomotion and chemotaxis are usually assayed by the Boyden chamber technique, in which the response is measured by microscopical counting of the cells migrated into a micropore filter. We report a simplified Boyden chamber method which utilizes myeloperoxidase (MPO) specific to neutrophilic and monocytic leukocytes. The chamber is incubated for a period long enough for the neutrophils to migrate through the first of two superimposed filters. The cells entering the second filter are then lysed and the released MPO activity is quantitated. Random migration, chemokinesis, and chemotaxis measurements of neutrophils were compared by the enzymatic and the conventional cell count methods. There was good agreement between the two methods (0.84 less than r less than 0.98). The intraassay precision of the enzymatic and the cell count methods was equal; the coefficients of variation were 14 and 15%, respectively. The enzymatic method provides a more objective, reliable, and rapid modification of the Boyden chamber assay for analysis of neutrophil chemotaxis.

Can early asthma be confirmed by laboratory tests

We examined the performance of a number of laboratory tests in 23 patients who had had symptoms suggesting asthma, such as cough, sputum secretion, and chest tightness with wheezing, for less than a year. Even the best test, histamine challenge, had a sensitivity of only 48%. When more tests were added, sensitivity rose: with peak expiratory flow added, the sensitivity was 65%; with sputum eosinophil cationic protein (ECP) added, to 74%; and with serum ECP added, to 78%. Thus, a combination of tests measuring lung function and activation of eosinophils yielded fair, if not good, results. It appears that sensitivity could be increased further through the development of improved sputum tests.

Detection and treatment of early asthma.

Background: We sought answers to two questions: