Differential IgE reactivity to Der p 1 and Der p 2 allergens of Dermatophagoides pteronyssinus in mite-sensitized patients.

Several studies have shown that the presence of IgE antibodies to house dust mites (HDM), particularly Dermatophagoides pteronyssinus (Dpt), is an important risk factor for asthma. Allergen immunotherapy is indicated for patients with IgE antibodies to clinically relevant allergens. The aims of this study were to analyze the levels of specific serum IgE to Der p 1 and Der p 2 allergens in mite-sensitized atopic patients and to compare them with both in vivo (skin prick test) and in vitro (IgE-ELISA) sensitizations to Dpt crude extract. Forty-seven atopic patients with allergic rhinitis with or without intermittent or persistent mild asthma and positive skin prick test (SPT) to Dpt total extract were studied. Thirty age-matched healthy subjects with negative SPT to HDM were included as controls. Levels of total IgE and Dpt-, Der p 1- and Der p 2-specific IgE were measured by ELISAs in SPT-positive atopic patients and SPT-negative control subjects. Among 47 symptomatic atopic patients, 27 (57.4%) were double positive IgE to Der p 1 and Der p 2 allergens, 3 (6.4%) were single positive IgE to Der p 1, 4 (8.5%) were single positive IgE to Der p 2, and 13 (27.6%) were double negative IgE to both allergens. There was a significant correlation between Der p 1- and Der p 2-specific IgE levels, but not between Der p 1- or Der p 2-IgE levels and SPT results. The double negative IgE patients had the smallest skin test reactions although they showed high mean levels of total serum IgE. Therefore, the knowledge of specific IgE levels to Der p 1 and Der p 2 major allergens might support physicians for indication or follow-up in mite-sensitized patients under allergen-specific immunotherapy. These approaches might be important for obtaining improved safety and efficacy of the current clinical practice of allergen immunotherapy.

Levels of GM-CSF, IL-3, and IL-6 in fluid and tissue from human radicular cysts.

Cytokines released by immune system cells play an important role in cyst enlargement. This study aimed to determine, by ELISA, the levels of granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin 3 (IL-3), and IL-6 in fluid and tissue from human radicular cysts. GM-CSF was found in 42.8% of the fluid samples (164.3 pg/mL) and IL-6 in 92.8% (641.4 pg/mL). No IL-3 was detected in any fluid samples. In the tissue samples, 28.6% were positive for IL-3 (369.2 pg/mL), 86.4% for IL-6 (92.4 pg/mL), and 95.8% for GM-CSF (200.5 pg/mL). It can be concluded that GM-CSF and IL-6 were widely found in the fluid and tissue samples. In contrast, IL-3 was found only in the cystic tissue, even though in few lesions. These cytokines may contribute to the inflammation, cystic growth, and bone resorption that characterize cystic lesions.

A sensitive reverse ELISA for the measurement of specific IgE to Der p 2, a major Dermatophagoides pteronyssinus allergen.

BACKGROUND: Epidemiologic studies have shown that the presence of IgE antibodies to house dust mite and other indoor allergens is an important risk factor for asthma. OBJECTIVE: The aim of this study was to develop a reverse ELISA (rELISA) for measuring specific IgE to Der p 2, a major Dermatophagoides pteronyssinus (Dpt) allergen, as a potential tool for followup of allergen immunotherapy. METHODS: Recombinant Der p 2 allergen or a monoclonal antibody to Der p 2 was used to coat plates in conventional ELISA (cELISA) and rELISA, respectively. Sera from 48 asthmatic patients with positive skin prick test (SPT+) to D. pteronyssinus extract were analyzed for total IgE and specific IgE to Der p 2, and the results were compared with a group of 41 SPT asthmatic and 30 SPT- control subjects. RESULTS: The sensitivity of the two assays for Der p 2-specific IgE was 3.9 EU/mL and their specificities were confirmed by inhibition tests, in a dose-dependent manner. There was a significant positive correlation between cELISA and rELISA (r = 0.74; P < 0.0001). However, rELISA was more sensitive than was cELISA, regarding both the positive sera percentage (70.8% vs 52.1%) and the Der p 2-specific IgE levels (28.4 vs 4.5 EU/mL) in SPT+ asthmatic patients. CONCLUSIONS: rELISA has shown to be a sensitive and alternative method for measuring Der p 2-specific IgE without using radioactive techniques. Detection of specific IgE to major allergens and relevant peptides, and identification of B cell epitopes in allergens will provide valuable information for the design of allergen analogs and peptides for immunotherapy.