Specific IgE against the house dust mite allergens Der p 5, 20 and 21 influences the phenotype and severity of atopic diseases.

BACKGROUND: House dust mites (HDM) are among the most important sources for airborne allergens with high relevance for atopic diseases. Routine tests contain only 4 of 32 registered allergens of Dermatophagoides pteronyssinus. Clinical relevance and pathomechanistic properties of many allergens are not well understood. OBJECTIVE: The association of several HDM allergens with allergic rhinitis, allergic asthma, and atopic dermatitis was investigated to identify allergens with biomarker potential and to transfer them into diagnostics. METHODS: Eight out of nine D. pteronyssinus allergens (nDer p 1, rDer p 2, rDer p 5, rDer p 7, rDer p 10, rDer p 13, rDer p 20, rDer p 21, rDer p 23) were recombinantly expressed and purified. Sensitization patterns of 384 HDM-allergic individuals exhibiting different clinical phenotypes were analyzed with a serum-saving multiplex array. RESULTS: Sensitization to more than three mite allergens (sensitization count) was associated with allergic asthma and/or atopic dermatitis. Reactions to Der p 5 and Der p 21 were more frequent in allergic asthma compared to allergic rhinitis. Atopic dermatitis patients were more often sensitized to Der p 5, Der p 20, and Der p 21 among others. Der p 20-IgE > 80 kU/L was associated with severe atopic dermatitis in 75% of patients. CONCLUSION: This study demonstrates the clinical importance of the sensitization count and of certain allergens (Der p 5, Der p 20, and Der p 21) not available for routine diagnostics yet. Implementing them as well as the sensitization count in diagnostic measures will improve diagnosis and risk assessment of HDM-allergic patients.

Exacerbation of atopic dermatitis on grass pollen exposure in an environmental challenge chamber.

BACKGROUND: It has frequently been speculated that pruritus and skin lesions develop after topical exposure to aeroallergens in sensitized patients with atopic dermatitis (AD). OBJECTIVE: We sought to study cutaneous reactions to grass pollen in adult patients with AD with accompanying clear IgE sensitization to grass allergen in an environmental challenge chamber using a monocenter, double-blind, placebo-controlled study design. METHODS: Subjects were challenged on 2 consecutive days with either 4000 pollen grains/m(3) of Dactylis glomerata pollen or clean air. The severity of AD was assessed at each study visit up to 5 days after challenge by (objective) scoring of AD (SCORAD). Additionally, air-exposed and non-air-exposed skin areas were each scored using local SCORAD scoring and investigator global assessments. Levels of a series of serum cytokines and chemokines were determined by using a Luminex-based immunoassay. The primary end point of the study was the change in objective SCORAD scores between prechallenge and postchallenge values. RESULTS: Exposure to grass pollen induced a significant worsening of AD. A pronounced eczema flare-up of air-exposed rather than covered skin areas occurred. In grass pollen-exposed subjects a significantly higher increase in CCL17, CCL22, and IL-4 serum levels was observed. CONCLUSIONS: This study demonstrates that controlled exposure to airborne allergens of patients with a so-called extrinsic IgE-mediated form of AD induced a worsening of cutaneous symptoms.