comparison of immunosuppressive effects of cyclosporin a and dexamethasone on invasive aspergillosis in experimental animals

in this study, 60 female, new zealand white rabbits were chosen and divided into 3 groups . the animals in group 1&2 were immunosuppressed with dexamethazone and cyclosporin a (cya) respectively. the animals in group 3 (control animals) were not immunosuppressed. in each group, half of the rabbits were infected intratracheally and the other half were infected intravenously with 4 conidia of aspergillus fumigatus . none of the 20 control animals showed any clinical symptoms.all the rabbits in groups 1&2, which were infected intravenously, developed clinical signs of invasive aspergillosis. however, of these 2 groups the rabbits which were given the conidia intratracheally , only 7 of 10 animals in group 1 demonstrated clinical signs of aspergillosis. at autopsy there was macroscopic and microscopic evidence of invasive aspergillosis. histopathological examination revealed hyphae invasion in liver, lung, brain and spleen. we conclude, in natural conditions that aspergillosis is initiated by inhalation of airborn condidia, cortison-treated patients are more susceptible to invasive aspergillosis than individuals who received cy-a.