Allergenic cross-reactivity of Curvularia lunata with other airborne fungal species

BACKGROUND: Curvularia lunata is an important fungus for respiratory allergic disorders. Previous studies indicated cross-reactivity of Curvularia with other fungi. However, the cross-reactive allergenic component (s) were not identified. The present work was carried out to study the shared allergenic components of C. lunata and others. METHODS: Cross-reactivity studies were performed using pooled hypersensitive patient sera to C. lunata by ELISA, immunoblot, immunoblot inhibition and ELISA inhibition. RESULTS: Many C. lunata sensitive patients showed positive skin test to five other fungi. Alternaria alternata exhibited maximum (68%) whereas Cladosporium herbarum showed the least (17%) skin reactivity. Immunoblots of fungal extracts with pooled sera showed common proteins. Fusarium solani and C. herbarum showed negligible IgE binding. IgE ELISA inhibition with C. lunata showed 92% inhibition whereas A. alternata and E. nigrum showed 84% and 63%, respectively. Immunoblot inhibition with self protein showed complete loss of IgE-binding activity. Proteins of 26, 31, 38, 45 and 50 kDa of C. lunata were inhibited by A. alternata and E. nigrum, whereas A. fumigatus inhibited 26, 45 and 50 kDa proteins. CONCLUSIONS: Significant allergenic cross-reactivity exists among proteins of C. lunata, A. alternata and E. nigrum. Proteins of 26, 31, 38, 45 and 50 kDa are shared allergens in these fungi.