ABSTRACT: At present the diagnosis of IgE-mediated hypersensitivity to phthalic anhydride (PA) is based on conjugates that are not characterized or standardized. The aim of this study was to develop optimized and molecularly characterized PA conjugates that can be used to improve the diagnosis of PA-allergy.
The PA conjugates were synthesized and the number of haptens bound on a carrier protein was estimated by matrix-assisted laser desorption/ionization time of light (MALDI-TOF) mass spectrometry. The ability of conjugates to bind IgE and IgG antibodies was measured by enzyme-linked immunosorbent assay (ELISA). Reactivity of the conjugates in vivo was evaluated by skin prick testing.
The most active IgE-binding conjugates had a PA : HSA molar ratio of 80 : 1. In the optimal conjugates the average numbers of PA haptens per carrier molecule of human serum albumin (HSA) were 14-16. In ELISA, all 13 patients and none of the 20 controls had IgE antibodies to optimized PA conjugate. The sensitivity and specificity of the ELISA was comparable to commercial CAP RAST. PA conjugates elicited positive test results in skin prick testing showing that conjugates are immunologically active also in vivo.
These results indicate that optimized and molecularly characterized PA-HSA conjugates can be used both in vitro and in vivo assays to improve the diagnosis of PA allergy.
Allergy 11/2002; 57(10):894-9. · 6.27 Impact Factor
Contact Dermatitis 03/2001; 44(2):129. · 3.51 Impact Factor
ABSTRACT: Food-dependent, exercise-induced anaphylaxis is a severe form of allergy; the reaction is caused by ingestion of a specific food before exercise. This disorder often escapes diagnosis because neither the ingested food nor the exercise alone induces the symptoms.
The aim of the study was to characterize the allergens involved in wheat-dependent, exercise-induced anaphylaxis and to describe the clinical outcome in a series of 18 adult patients.
All 18 patients had experienced recurrent episodes of generalized urticaria during exercise, 17 patients in association with collapse and 15 patients with an anaphylactic reaction. The symptoms appeared only when the patients had eaten food containing wheat before exercise. Wheat allergens were detected by immunoblotting, purified by gel filtration and reversed-phase chromatography, and subjected to N-terminal sequencing. The IgE-binding ability of the purified proteins was studied by ELISA, and their in vivo reactivity was studied by skin prick testing.
IgE antibodies from pooled patient sera were bound to 65-kd and 40-kd wheat proteins in immunoblotting. The 65-kd allergen was a previously undescribed wheat protein, showing 61% sequence identity to gamma-gliadin, whereas the 40-kd allergen had 100% identity to alpha-gliadin. In ELISA, all 18 patients showed elevated IgE levels to the novel gamma-like gliadin, and 13 of the patients showed elevated IgE levels to the alpha-gliadin. None of the 54 control subjects with wheat allergy, urticaria, or coeliac disease had IgE antibodies to the gamma-like gliadin. The in vivo reactivity of the gamma-like gliadin was verified by positive skin prick test responses in all of the 15 patients who were tested. During the follow-up on a gluten-free or wheat-free diet, 3 patients experienced reactions after having unknowingly eaten wheat before exercise, but all the other patients who were adhering to the diet remained symptom-free.
This study shows that wheat is a frequent cause of food-dependent, exercise-induced anaphylaxis and suggests that the major allergen is a previously undescribed gamma-like gliadin. For screening of this life-threatening allergy, we recommend skin prick testing with crude gliadin and we recommend a gluten-free diet for treatment.
Journal of Allergy and Clinical Immunology 06/1999; 103(5 Pt 1):912-7. · 11.00 Impact Factor
ABSTRACT: Topical corticosteroids are the mainstay of treatment in inflammatory skin diseases. Corticosteroids penetrate human skin, especially when the penetration barrier is damaged. Whether long-term application of topical corticosteroids can lead to alteration of immune responses is not clear. We sought to examine the impact of topical corticosteroids on immune responses in patients using long-term topical corticosteroids. Peripheral blood mononuclear cell proliferation in response to tetanus toxoid and tuberculin stimulation was studied, and tetanus toxoid-specific antibodies were examined with ELISA. The results showed that, compared with the control group, the stimulation indices of patients' peripheral blood mononuclear cell to tetanus toxoid and tuberculin stimulations were lowered, which was especially significant in the tetanus toxoid group. No significant decrease was found in serum levels of tetanus toxoid-specific antibody. The results suggest that topical corticosteroids can suppress cell-mediated immune response in patients using long-term topical corticosteroids.
Acta Derm Venereol. 85(4):296-8.