Lars Belin

Asthma, rhinitis, and dermatitis in workers exposed to reactive dyes.

A survey was conducted at 15 textile plants with dyehouses in western Sweden. Employees with a history of work related rhinitis, asthma, or skin symptoms were offered a clinical and immunological investigation including skin prick tests, skin patch tests, and radioallergosorbent tests (RASTs) to detect specific allergy to reactive dyes. Among the 1142 employees, 162 were exposed to reactive dyes and 10 of these (6%) reported work related respiratory or nasal symptoms. An allergy to reactive dyes could be confirmed in five (3%, 95% confidence interval 1-7%). All but one had been exposed to reactive dyes for one year or less before the onset of symptoms. Positive RASTs could be detected in four of the five patients. All of the RAST positive patients were positive to remazol black B, but six out of eight additional remazol dyes also elicited positive results. RAST and RAST inhibition showed a cross reactivity between some of the dyes. Seven persons with work related dermatitis and three with urticaria or Quincke oedema were found. In one patient contact dermatitis to a monoazo dye was shown, but no positive patch test reactions to reactive dyes. IgE-mediated allergy to reactive dyes seems to be an important cause of respiratory and nasal symptoms among dyehouse employees exposed to dust from reactive dyes.

Immunologic specificity of isocyanate-induced IgE antibodies in serum from 10 sensitized workers☆

A procedure for the preparation of RAST disks used to assay isocyanate-specific IgE antibodies was developed. The outcome of the RAST was found to be strongly dependent on how the isocyanate test antigen was synthesized. Specific IgE from selected workers with isocyanate asthma reacted optimally to conjugates with less than or equal to 10 isocyanate molecules bound per molecule of human serum albumin. Further haptenization resulted in decreased specific binding and increased nonspecific binding because of high levels of total IgE. The hapten and carrier specificity of isocyanate-induced IgE antibodies were studied by direct RAST and RAST inhibition. The existence of new antigenic determinants related to both the isocyanate hapten and the carrier could be demonstrated. It was important to use a test antigen prepared from the same isocyanate as that to which the worker had been exposed, since the cross-reactivity between different isocyanate haptens was partial and varied from one patient to another. It was confirmed that isocyanate-specific IgE antibodies can be demonstrated only in a subgroup of workers with isocyanate-related bronchial asthma.

Rapidly released allergens from short ragweed pollen. I. Kinetics of release of known allergens in relation to biologic activity.

Study of the kinetics of in vitro release of known antigens from short ragweed pollen revealed a slow release of AgE (1.5% to 4% release after 16 min) but a rapid release of other highly allergenic components. The rapidly released allergens in 16-min pollen extracts were found to be mainly highly basic proteins including the well-characterized Ra5 molecule along with several hitherto uncharacterized components. Considering previous data that suggest that particles of a similar size to ragweed pollen grains remain in the nose only about 6 to 8 min following inhalation, it is difficult to explain the apparent anomaly between the high biologic potency of 16-min extracts and their low AgE content. Increase in the pH of the extracting buffer from the physiologically normal nasal plH of 5.5 to 6.5 to about pH 8.0 to 8.5 (characteristically found in rhinitis) increased the proportion of AgE released after 16-min extraction by about 10-fold, suggesting that response to allergens in ragweed and other inhalants may enhance AgE release and thereby aggravate allergic symptoms. Detailed comparison of the allergenic activity of AgE and of 16-min and 4-day ragweed extracts in 38 ragweed-sensitive subjects suggested that allergens other than AgE were together more important than AgE in causing ragweed allergy in most patients, although large patient-to-patient differences in relative response were observed. Our data emphasize the need to reevaluate materials used in both diagnosis and treatment of ragweed allergy. The importance of AgE relative to other ragweed pollen components with respect to induction of allergic symptomatology deserves to be placed in a more balanced perspective.

Breed-specific dog-dandruff allergens

Fifty-one patients with clinical history of dog allergy were skin prick tested with eight individual standardized dog breed-allergen preparations, one mixed breed-allergen preparation (Poodle/Alsatian), dog-serum albumin, and histamine hydrochloride, 1 mg/ml. All extracts were characterized by crossed immunoelectrophoresis and crossed radioimmunoelectrophoresis with a pool of sera from patients clinically sensitive to dog. The dog-breed extracts contained common antigens/allergens, as well as components represented only in one or two dog-breed extracts. The concentration corresponding 1000 BU/ml varied from 16 to 100 micrograms of protein per milliliter. The sensitivity of skin prick test was 67% to 88% for the various dog breed-allergen preparations, but only 18% for dog-serum albumin. Significant difference between the skin test response to different dog breed-allergen preparations indicating dog breed-specific allergens was obtained in 15% of the patients. There was no significant correlation between skin prick test results and symptoms related to a specific dog breed.

Assay of specific IgE antibodies to disodium cromoglycate in serum from a patient with an immediate hypersensitivity reaction

A 29-year-old man with pollen allergy had experienced immediate adverse reactions, such as itching of the eyes, rhinitis, wheezing, and general urticaria, after using disodium cromoglycate (DSCG) eye drops. The local symptoms were reproducible, and skin tests were strongly positive. With serum from the patient, a RAST was developed for the assay of IgE antibodies. The uptake on RAST disks was 6% of the total activity added, which was a significantly higher level than was found in sera from 35 randomly selected blood donors or in sera from 25 patients tolerating DSCG. By addition of DSCG to the patients serum, 95% of the binding to paper disks could be inhibited. The induction of specific IgE antibodies was proposed to be a result of a combination of electrostatic and hydrophobic interaction of DSCG and a protein carrier. The substance would thus act as a hapten without any covalent binding to the carrier. DSCG may serve as a model for other nonreactive low-molecular-weight substances suspected to elicit type I-like adverse reactions.