IL-3, IL-5, and granulocyte-macrophage colony-stimulating factor potentiate basophil mediator release stimulated by eosinophil granule major basic protein.

We have examined the potential of IL-3, IL-5, and granulocyte-macrophage (GM)-CSF to enhance basophil activation by eosinophil granule major basic protein (MBP). Preincubating basophil-containing mononuclear cells with 0.01 to 10 ng/ml IL-3 or IL-5 for 15 min at 37 degrees C caused a concentration-dependent enhancement of histamine release stimulated by 1.5 microM MBP. Statistically significant enhancement was evident at 1 ng/ml and was maximal at 10 ng/ml. Preincubation with GM-CSF similarly enhanced MBP-induced histamine release. A 10- to 15-min preincubation with IL-5 maximally increased the level of MBP-stimulated histamine release. Preincubation of cells with 10 ng/ml IL-3 or IL-5 reduced the MBP concentrations required for histamine release by three- to fourfold and enhanced the rate of MBP-induced histamine release. MBP-stimulated histamine release before or after cytokine priming was independent of cytotoxicity as measured by 51Cr release. Consistent with a direct action of the cytokines on basophils, flow cytometric analysis demonstrated the presence of IL-3 and GM-CSF receptors on basophils. MBP also stimulated low levels of leukotriene C4 (LTC4) release from basophils of 84 to 99% purity, and experiments using enriched (18-63%) basophil preparations demonstrated that preincubation with IL-3, IL-5, and GM-CSF also potentiated MBP-stimulated leukotriene C4 release up to threefold in parallel with histamine release. These results indicate that IL-3, IL-5, and GM-CSF may contribute to the pathogenesis of allergic and other disorders characterized by eosinophilia in part through potentiation of basophil mediator release stimulated by MBP.

Anaphylaxis following ingestion of a psyllium-containing cereal.

Recently, psyllium hydrophilic mucilloid, a bulk-forming laxative, has been added to breakfast cereals for cholesterol-lowering effects. We report a case of a 60-year-old woman with no prior history of psyllium ingestion who developed anaphylactic symptoms after eating a psyllium-containing cereal. Her only previous exposure was dispensing a psyllium-containing laxative as a nurse. Immunoglobulin E-mediated sensitization was documented by skin testing and basophil histamine release. The literature is reviewed regarding allergic reactions to psyllium. Health care workers and pharmaceutical workers handling psyllium may be at increased risk due to sensitization from inhalation. Physicians and consumers should be aware of potential serious reactions from eating psyllium-containing cereals even without prior history of ingestion of psyllium.

IgE-mediated sensitivity to Trichophyton rubrum in a patient with chronic dermatophytosis and Cushing's syndrome.

Persistent Trichophyton rubrum infection has been observed previously in association with Cushing's syndrome. In this article, we demonstrate IgE-mediated sensitivity to Trichophyton in a patient with chronic dermatophytosis secondary to Cushing's syndrome. Cell-mediated immunity was absent, but Trichophyton extract produced an immediate skin response and also stimulated a concentration-dependent histamine release from basophils of the patient. After adrenalectomy, cell-mediated immunity to Trichophyton was restored, and infection was confined to the nails. Skin and leukocyte sensitivity to Trichophyton extract persisted and was even more pronounced than the sensitivity before adrenalectomy. RAST measurement confirmed the presence of Trichophyton-specific IgE after adrenalectomy. These results provide further evidence that IgE-mediated inflammatory events may be initiated by Trichophyton infection.