Diagnostic value of Alt a 1, fungal enolase and manganese-dependent superoxide dismutase in the component-resolved diagnosis of allergy to pleosporaceae

Abstract

Over the last decades, genomics and proteomics have contributed to the current knowledge of individualized allergenic components and their potential use in the diagnosis of IgE-mediated allergies. Recent investigations have demonstrated that Alt a 1 should be considered as a relevant allergen of the Pleosporaceae group and that enolase is the main allergen involved in the cross-reactivity to fungi. However, the real utility of these allergens as tools for the diagnosis of allergy to Alternaria is still unclear. To demonstrate the current value of the available fungal allergen panel and the need to build an accurate mould allergen array for the diagnosis of allergy to Pleosporaceae. Specific IgEs to individual mould allergens and allergenic mould extracts were evaluated using the ImmunoCAP™ system in 30 patients allergic to Alternaria and in 100 blood donors. Cross-reactivity studies were performed by Fluoro Enzyme ImmunoAssay (FEIA) and FEIA inhibition using individual allergens and allergenic extracts. Two-dimensional electrophoresis associated with a MALDI-TOF analysis was carried out to identify new allergen molecules. All allergic patients had positive specific IgE responses to several moulds from different taxonomical families. Classic and molecular diagnosis demonstrated that 23% of patients had multi-sensitization. The current commercially available fungal allergen array was not sufficient to establish an accurate diagnosis. Unexpected correlations between Alternaria or Alt a 1 and Curvularia or Cladosporium stimulated the investigation of a more accurate allergen panel. A manganese-dependent superoxide dismutase (MnSOD) homologous to Asp f 6 was identified as a new IgE-binding molecule from Alternaria alternata. Alt a 1 is the marker for allergy to Pleosporaceae, not including Curvularia. MnSOD can explain 6.6% of allergy to Alternaria without Alt a 1 sensitization and should be included together with Alt a 1 and fungal enolase in the molecular array for the diagnosis of allergy to Pleosporaceae.