Characterization of the allergen(s) in latex protein extracts.

BACKGROUND: Immediate hypersensitivity to latex, induced by natural latex proteins remaining on the finished products, may lead to severe anaphylactic reactions. METHODS: We investigated the distribution of latex proteins by molecular weight and identified the specific allergenic molecules. Proteins extracted from various latex products were compared with those extracted from raw latex sap, both ammoniated and nonammoniated. RESULTS: Variations in the levels of extractable protein, as well as in the number of molecules and the molecular weight distribution, were observed especially among finished latex products. To identify allergenic (i.e., IgE-binding) molecules, we performed immunoblots with the sera from latex-sensitive persons. The results indicated that antigenic molecule profiles differed among the products and also between the finished products and the raw material. In addition, specificities of the anti-latex IgE antibodies varied among the sensitized persons. CONCLUSIONS: It appeared that persons with the same history of sensitization had similar patterns of antigenic specificities. If the history of exposure, as well as genetic predisposition and medical history of the patient, plays a significant role in the specific IgE response, it may be difficult to select a "standard" antigen and a "standard" antiserum for the evaluation of the latex sensitivity and allergenicity.

Cornstarch powder on latex products is an allergen carrier.

Allergic reactions of the upper respiratory tract during use of powdered latex rubber gloves have been recently associated with sensitivity to latex. We have studied the ability of cornstarch powder to bind latex proteins and evaluated allergenic properties of the bound protein. Allergenicity was determined by competitive inhibition of human anti-latex IgE binding to solid-phase latex antigen. Cornstarch extracted from powdered latex products and clean cornstarch exposed to latex protein extracts were evaluated in comparison with clean unexposed cornstarch. Both exposed cornstarch preparations inhibited specific binding of anti-latex IgE antibodies to latex proteins in a dose-response manner. Latex-exposed cornstarch diluted 50% vol/vol produced complete inhibition, whereas greater dilutions exhibited variable levels of inhibition, depending on the source of cornstarch-bound proteins, insolubilized latex proteins, and IgE antibody-containing human serum used. Cornstarch not exposed to latex had no inhibitory activity. The study demonstrates that cornstarch indeed binds allergenic latex proteins and supports the causative relationship between allergic reactions in individuals with latex sensitivity and the exposure to airborne particles from powdered latex products.

Latex-associated allergies and anaphylactic reactions.

The recent reports of severe anaphylactic reactions and several fatalities caused by contact with latex-containing products raised concerns in the medical community. Although hypersensitivity to natural rubber has been widely reported in the literature, the prevalence and severity of reactions have rapidly increased in the last few years. Latex proteins, constituents of natural latex, appear to be responsible for the sensitization. Many investigators, including our laboratory, are focused on the identification of proteins in raw latex and latex products, specifically those responsible for the elicitation of allergic responses. This paper summarizes available information on the mechanism and epidemiology of latex sensitivity and reviews research efforts toward the identification of the antigen(s) responsible for the reactions. The questions of proper diagnosis and testing, heightening awareness, and prevention of reactions are also addressed.

Cytotoxicity and mutagenicity of ophthalmic solution preservatives and UVA radiation in L5178Y cells.

Four chemical preservatives commonly used in ophthalmic solutions were tested for their toxic and mutagenic potential in mouse lymphoma cells with and without exposure of the cells to ultraviolet A (UVA) radiation. The preservatives tested were benzalkonium chloride (BAK), chlorhexidine, thimerosal and ethylenediaminetetraacetic acid (EDTA). Cell survival and mutagenesis were measured using the L5178Y mouse lymphoma (TK +/-) system. Cells were exposed to varying amounts of preservatives for 1 h at 37 degrees C, and then aliquots were irradiated with UVA radiation (during the exposure to preservative). Cells were then assayed for survival, and for mutagenesis at the thymidine kinase (TK) locus. In concentrations commonly found in ophthalmic solutions, BAK, chlorhexidine, and thimerosal were toxic to cells, and thimerosal was slightly mutagenic. When cells were exposed to preservative and UVA radiation, chlorhexidine was mutagenic and the mutagenic activity of thimerosal was enhanced.