Participates in various redox reactions through the reversible oxidation of its active center dithiol to a disulfide and catalyzes dithiol-disulfide exchange reactions. Causes an allergic reaction in human (PubMed:17182577, PubMed:19032234). Recombinant protein binds to IgE in atopic eczema-suffering patients allergic to yeast M.sympodialis (PubMed:17182577). Recombinant protein binds to IgE in 50% of the 40 patients tested suffering from allergic bronchopulmonary aspergillosis (ABPA). Causes a positive skin reaction and induces proliferation of the human peripheral blood mononuclear cells in ABPA patients allergic to this protein (PubMed:19032234). Belongs to the thioredoxin family.