Hamid Nawaz Tipu and Dawood Ahmed
Aspergillus fumigatus is the commonest mold implicated in pathogenesis of allergic broncho pulmonary aspergillosis (ABPA), condition almost exclusively seen in patients with asthma and cystic fibrosis . Several immunological mechanisms have been implicated including immediate hypersensitivity (type I), antigen antibody complexes (type III) and inflammatory cell responses (type IV) according to the Gell and Coombs classification. One component of the involved complex pathogenetic mechanism is that antigens from inhaled conidia are processed and presented to T lymphocytes with activation of Th2 CD4+ T cells. The release of Th2 pathway cytokines (IL-4, IL-5 and IL-13) leads to IgE synthesis, mast cell degranulation and an eosinophilic response.