Epicoccum allergy: skin reaction patterns and spore/mycelium disparities recognized by IgG and IgE ELISA inhibition.

Comparable degrees of skin reactivity were observed towards spore and mycelium extracts from two isolates of Epicoccum and to one preparation of Alternaria in 35 rural and 120 university patients. The best experimental extracts detected Epicoccum sensitivity in 70% of the group tested while the commercial extract detected sensitivity in only 6%. Skin reaction correlations were greatest within isolates (eg, spore-A/mycelium-A), then for specific fungus parts (eg, spore-A/spore-B), then between isolates and parts (spore-A/mycelium-B). High correlations were found between individual IgG and IgE ELISA values for all antigens using serum from Epicoccum skin-reactive patients. ELISA inhibition results suggested that significant cross-reactivity exists between Epicoccum and Alternaria antigens recognized by IgG but not by IgE. ELISA inhibition cross-reaction patterns among Epicoccum antigens were comparable to skin reactions while IgG patterns showed little variability. Further characterization of spore/mycelium and interstrain recognition patterns among different immunoglobulin isotypes will be necessary before complete standardization of extracts from different parts of fungi will be possible. The use of spore material for skin testing and treatment of Epicoccum sensitivity appears to be both premature and unnecessary at this time.