Evaluation of IgE-sensitization to fungi in HIV-positive patients with eczematous skin reactions

Background: Human immunodeficiency virus infection is associated with decli ning immune function and polyclonal B-cell activation leading to elevated I gE-levels. In selected patient categories, increased total IgE may be assoc iated with allergic diseases. Furthermore, a significant number of patients with low CD4+ cell numbers have various skin manifestations, eg, eczema an d dermatophytosis. Patients with chronic fungal infections and a tendency t o produce increased levels of specific IEE may become allergic and IgE-medi ated mechanism may contribute to inflammatory reactions in the skin. Objective: This study investigates IgE-sensitization of patients infected w ith human immunodeficiency virus to a panel of fungal extracts of Candida a lbicans, Fusarium moniliforme, Penicillium notatum, Pityrosporum ovale, and Trichophyton rubrum. Methods: Fifteen HIV-positive patients with eczematous skin manifestations and five non-atopic healthy controls were evaluated by basophil histamine r elease and skin prick test with fungal extracts. The extracts were separate d by sodium dodecylsulfate-polyacrylamide gel electrophoresis under reducin g conditions and analyzed by IgE-immunoblotting with sera from the patients and controls. Results: Thirteen of 15 patients (87%) released histamine to one or more of the fungi. Skin prick test was positive to one or more fungi in 7 (47%) pa tients. Patient sera revealed binding to a wide range of IgE-binding compon ents present in the fungal extracts. The IgE response was most often direct ed against a 46-kD main protein in the Candida albicans extract. There was no correlation between total serum IgE, CD4+ cell counts, and frequency of IgE-sensitization to fungi. Conclusion: The human IgE response in HIV-infected patients appears to be p olyspecific and may be directed against various fungi of which Candida albi cans may be an important allergen. It is possible that the sensitization is due to frequent infections with Candida albicans in this patient populatio n. No unspecific fungal reactions were noted among control patients, These results suggest that allergen-specific IgE-mediated mechanism may contribut e to the pathogenesis of the eczematous skin reaction in HIV-infected patie nts.