Jerome Glaser lectureship. The role of food allergy and mediator release in atopic dermatitis

Recombinant gamma interferon in treatment of patients with atopic dermatitis and elevated IgE levels

PURPOSE

Recombinant gamma interferon (rIFN-gamma) inhibits IgE synthesis in vitro by human peripheral blood mononuclear cells (PBMC). These data suggest a role for rIFN-gamma in the treatment of patients with severe atopic dermatitis (AD) and elevated IgE levels. The purpose of this study was to determine the effect of rIFN-gamma treatment on IgE production in patients with AD.

PATIENTS AND METHODS

Twenty-two patients with chronic severe AD were treated with rIFN-gamma. In part I of the study, 14 patients were treated with daily subcutaneous injections at three successive dose levels (0.01 mg/m2, 0.05 mg/m2, and 0.1 mg/m2) for 5 days with 2 days off between each dose level. In part II, eight patients received rIFN-gamma at 0.05 mg/m2, daily for 6 weeks. One patient from part I and eight patients from part II of the study received three times per week maintenance thereby for up to 14 months. Prior to and at selected times during and after treatment, the clinical and immunologic status of the patients was assessed.

RESULTS

In part I, spontaneous de novo IgE synthesis by PBMC was inhibited in 10 patients receiving rIFN-gamma at 0.01 mg/m2 (p = 0.038) and in nine at 0.1 mg/m2 (p = 0.066). There was no reduction of serum IgE levels at any of the three dose levels. Total clinical severity showed improvement at each dose level (p less than 0.04) with worsening 3 days after discontinuation of treatment. In part II, there was no significant inhibition of spontaneous IgE synthesis by PBMC nor was there any reduction of serum IgE. Nevertheless, there was a progressive and significant reduction (p less than 0.01) in total clinical severity over the 6 weeks of daily rIFN-gamma with a sustained improvement during maintenance therapy.

CONCLUSION

The results of this pilot study suggest that rIFN-gamma may be efficacious in the treatment of AD and that further clinical trials are warranted.

The relationship between positive aeroallergen patch test reactions and aeroallergen exacerbations of atopic dermatitis

Previously we have demonstrated that patient contact with specific aeroallergens can cause flares of atopic dermatitis. In this study we report six additional cases that further document the relationship between positive aeroallergen patch test reactions and aeroallergen exacerbation of atopic dermatitis. In total, we have seen 18 patients (8 male, 10 female; ages 1-54 years) who have noted marked improvement in their skin symptomatology when antigen elimination (or moderation) was instituted as part of their general management. Delineation of inciting allergen was accomplished by a combination of prick tests and patch tests to aeroallergens. On prick testing all patients had markedly positive immediate wheal and flare reactions to a variety of aeroallergen extracts (tree, grass, and weed pollen, house dust mite, animal protein, and mold spores). The same patients were subsequently patch tested on uninvolved, nonabraded skin with allergen extracts at the same concentrations that had given positive prick tests. Patch tests were applied for 48 hr, removed, and interpreted at 48 and 72 hr. Patients reacted to specific aeroallergens with an eczematous eruption at 48 or 72 hr or at both time points. Positive delayed cutaneous reactions correlated strongly with aeroallergens identified in the patient's environment and/or suspected by the patients as inducers of dermatitis. Delayed cutaneous reactions were negative to allergens not historically relevant. Avoidance of aeroallergens that elicited an eczematous reaction at patch test sites resulted in marked improvement or resolution of dermatitis in all patients. Environmental rechallenge with incriminated allergens resulted in flares of dermatitis. We conclude that aeroallergen contact plays an important role in select patients with atopic dermatitis and that the responsible allergens can be elucidated by a combination of prick and patch tests.

Food and food additives in severe atopic dermatitis

In this study the role of food additives, tyramine and acetylsalicylic acid, was investigated by double-blind placebo-controlled challenges (DBPCC) in 25 children with severe atopic dermatitis (AD). All children challenged with foods (n = 24), except one, showed one or more positive reactions to the DBPCC with foods. Positive reactions presented as different combinations of flares of skin symptoms, intestinal symptoms and respiratory symptoms. Seventeen children (70.8%) showed a positive challenge to egg, 12 to wheat (50%), eight to milk (33.3%) and eight to soya (33.3%). Six children underwent DBPCC with food additives, tyramine and acetylsalicylic acid. All were found to demonstrate positive skin and/or intestinal reactions to at least one of the food additives. Two children reacted to tartrazine, three to sodium benzoate, two to sodium glutamate, two to sodium metabisulfite, four to acetylsalicylic acid and one to tyramine. It is concluded that some foods, food additives, tyramine and acetylsalicylic acid, can cause positive DBPCC in children with severe AD.

Cross-allergenicity in the legume botanical family in children with food hypersensitivity. II. Laboratory correlates

Only two of 41 legume-allergic patients diagnosed by double-blind, placebo-controlled oral food challenge or "convincing history" of anaphylaxis had an IgE-mediated hypersensitivity reaction to more than one member of the legume family. However, extensive immunologic cross-reactivity was demonstrated among legume antigens on Immunoblot and Immunodot-blot analyses and prick skin tests. The proteins of six legumes (peanut, soybean, lima bean, pea, garbanzo bean, and green beans) were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, transferred to nitrocellulose, and probed with sera from six legume-allergic patients. Multiple IgE-binding bands were identified in each legume lane by the sera from each of these legume-allergic patients. In vitro cross-reactivity did not correlate with clinical hypersensitivity. All the legumes studied (except green bean) had a prominent band at 20 kd. Numerous proteins and protein subunits can be identified in each of the legumes (16 peanut, 21 soybean, 23 lima bean, 25 pea, 22 garbanzo bean, and 11 green bean protein bands) by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and it appears that legume-allergic patients' sera may recognize multiple similar fractions from each legume. A second in vitro test was performed in which the six legume extracts were bound directly onto nitrocellulose paper. These "legume" Immunodot blots were probed for specific IgE-binding activity with sera from 62 patients with positive legume prick skin tests. The legume Immunodot blots again demonstrated extensive clinically irrelevant cross-reactivity. However, this test may prove useful as a simple technique for screening food-specific IgE with minimal quantities of sera.

Aeroallergen contact can exacerbate atopic dermatitis: patch tests as a diagnostic tool

Previous studies have documented that atopic dermatitis can worsen when patients ingest specific foods to which they are sensitive. In this article we demonstrate that patient contact with specific aeroallergens can cause flares of atopic dermatitis. Marked improvement in skin symptoms was noted when 12 patients (eight males and four females; ages, 1 to 54 years) were removed from their unusual environment. In response to prick tests, these patient had markedly positive, immediate wheel-and-flare reactions to a variety of aeroallergen extracts (tree, grass, and weed pollen; house dust mite; animal protein; and mold spores). The same patients were subsequently patch tested on uninvolved, nonabraded skin with the allergen extracts that had yielded positive prick tests. Patch tests were applied for 48 hours, removed, and interpreted 24 hours later. The patients reacted to specific aeroallergens with an eczematous eruption at 48 and 72 hours. Positive delayed cutaneous reactions correlated strongly with aeroallergens identified in the patient's environment or suspected by the patients as provocateurs of their atopic dermatitis. Delayed cutaneous reactions were negative to allergens not historically relevant. Continued avoidance of aeroallergens that elicited an eczematous reaction at patch test sites resulted in marked improvement or resolution of dermatitis in all patients. We conclude that aeroallergen contact plays an important role in select patients with atopic dermatitis.

Natural history of food hypersensitivity in children with atopic dermatitis

Patients with atopic dermatitis and food hypersensitivity who were adhering to an elimination diet underwent repeat double-blind, placebo-controlled oral food challenges annually for follow-up of their food allergy. After 1 year, 19 of 75 patients lost all signs of clinical food hypersensitivity (15 of 45 patients allergic to one food, and 4 of 21 allergic to two foods). Of the individual foods, 38 of 121 no longer elicited symptomatic responses. After 2 years, patients underwent a second rechallenge; 4 of 44 patients tested lost their clinical food hypersensitivity. In 20 patients undergoing a third rechallenge, no food hypersensitivity was lost. Loss rate of food hypersensitivity varied among foods; after 1 year, there was a 26% loss of symptomatic food allergy to five major allergens (egg, milk, soy, wheat, and peanut) compared with a 66% loss rate to other food allergens. Loss of symptomatic allergy was not affected by the patient's age at diagnosis, except with milk allergy, for which older patients were more likely to lose clinical food hypersensitivity (p less than 0.05). Total serum IgE and prick skin tests were not useful for predicting loss of symptomatic food hypersensitivity. There was no significant decrease in skin test wheal size corresponding to loss of clinical food hypersensitivity. Patients developing only skin symptoms during the initial challenge were most likely to lose symptomatic food hypersensitivity.