Background: There is increasing evidence that IgE-mediated reactivity against autoantigens could play a role in the pathology of severe chronic atopic diseases.
Methods: Human mitochondrial managenese superoxide dismutase (MnSOD), acidic ribosomal P2 protein and cyclophilins were cloned by PCR, expressed as inclusion body proteins in Escherichia coli, purified by Ni2+-chelate affinity chromatography, refolded in vitro and used for further experiments.
Results: Human MnSOD, P2 ribosomal protein and cyclophilins respectively, show sequence identity and similarity of >50% and 70% to the corresponding allergens of Aspergillus fumigatus. The human proteins were able to bind IgE from sera of individuals sensitized to the mould proteins and to elicit strong skin reactions of the immediate type in these individuals.
Conclusions: These observations provide evidence for autoreactivity to human proteins in allergic persons chronically sensitized to environmental allergens from A. fumigatus which share a high degree of sequence homology to the corresponding human proteins.