Nitrocellulose-RAST analysis of allergenic cross-reactivity of Candida albicans and Saccharomyces cerevisiae mannans.

Two chemically purified mannan preparations and one affinity purified mannan preparation of Candida albicans and Saccharomyces cerevisiae were analyzed for allergenic cross-reactivity. Simultaneous IgE binding in radioallergosorbent test (RAST) was studied with all preparations and the chemically purified mannans were also used for RAST inhibitions. The yeast mannans were purified with the Peat method, using repeated ethanol precipitations and Fehling's precipitation in alkaline conditions, and the Cetavlon method, using hexadecyltrimethylammonium bromide and ethanol precipitations. Affinity purification of the mannans was performed with concanavalin A lectin bound to a Sepharose column. Mannan from Pityrosporum ovale was purified with the Cetavlon method for analysis of simultaneous RAST reactivity. Simultaneous IgE binding to all the studied yeast mannans was generally seen in all the studied sera of patients suffering from atopic dermatitis. The strongest responses were seen against C. albicans mannan, especially the Cetavlon mannan. In the RAST inhibition studies IgE binding to S. cerevisiae mannan was completely inhibited by C. albicans mannan preparations, whereas reciprocal inhibition was not complete. These results indicate that in atopic dermatitis simultaneous IgE response to yeast polysaccharides occurs and that the major sensitizer is C. albicans and IgE antibodies against S. cerevisiae mannan are cross-reacting.