Flow cytometry versus histamine release analysis of in vitro basophil degranulation in allergy to Hymenoptera venom.

BACKGROUND: Flow cytometry (FCM) has been proposed for specific allergy in vitro testing. We investigated its biological significance for allergy to Hymenoptera venoms and compared it with the routinely performed basophil histamine release test (HRT). METHODS: Blood samples from 26 allergic and 8 nonallergic donors were incubated with venom at serial concentrations. Basophils were analyzed with anti-CD45-PE-Cyanin 5, Anti-IgE-FITC, and Anti-CD63-Phycoerythrine. HRT was measured by radioimmunoassay. RESULTS: FCM was as convenient as HRT for measuring basophil reactivity in at least 87% of allergic and 75% of nonallergic subjects. CD63 outer expression was specifically induced in 91% of releaser subjects (86% on HRT) and in 1 of 10 tests in nonallergic donors, or one of six tests (16% on HRT) in allergic patients tested with an irrelevant allergen. Both methods were concordant in 85.7% of the tests. The three discordant patients had low-grade reactions and borderline biological responses on FCM (n = 2) or HRT (n = 1). CONCLUSIONS: The dynamic, physiologic significance of CD63, the dose-response curve, and dependency on ethylene-diaminetetra acetic acid suggested that both tests reflect the same mechanism.

[Solar urticaria: one case treated by intravenous immunoglobulin]. / Urticaire solaire: un cas traité par immunoglobulines polyvalentes.

BACKGROUND: Solar urticaria is a rare photodermatosis which often begins from the third to the fifth decade. Usual treatment consists of photoprotection measures and antihistamines although disease control is sometimes unsatisfactory with both. We report herein a very severe case of solar urticaria we treated with intravenous immunoglobulins. CASE-REPORT: A 55-year-old woman suffered for 3 years from very severe solar urticaria which resisted treatment. Phototests revealed two action spectra: the first in UVA near 380 nm with a minimal urticarian dose of 0.025 J/cm(2), the second near 500 nm in visible light. RESULTS: As last resort treatment, we gave our patient intravenous immunoglobulins. After the third course of treatment, the improvement was impressive as the patient could tolerate visible light and 15 minutes of intense solar exposure. The minimal urticarian dose was raised from 0.025 J/cm(2) to 27 J/cm(2) in UVA. One year after treatment, the solar urticaria has disappeared. CONCLUSIONS: We report herein the first case of solar urticaria treated with success with immunoglobulin. Intravenous immunoglobulin treatment is well for its effectiveness in many autoimmune diseases such as autoimmune thrombocytopenic purpura, and also, as recently proven, in some cases of severe idiopathic chronic urticaria.