Experimental mycosis in immunosuppressed rabbits. II. Acute and chronic aspergillosis.

The influence of immunosuppression on the course of experimental aspergillosis was investigated. Rabbits (2.2--2.5 kg) were divided into four groups. Group one received no drugs and was given 10(6) spores intravenously (IV) or intratracheally (IT) on two occasions one week apart. Weight gain or loss, appearance or disappearance of aspergillus antigen and/or antibody, and detection of aspergillosis at autopsy were followed. Group 2 received weekly injections of cyclophosphamide (70 mg/kg) starting two weeks prior and throughout the experiment. Animals in group three received either 1.14 or 2.25 mg/kg/day methyl prednisolone and group four received 2.28 mg/kg/day methyl prednisolone and 70 mg/kg/week cyclophosphamide. In group one, serum antigen levels were detected within a week of infection followed by antibody (I.D.) levels for three months. All animals grew normally and no infection was detected at autopsy. In group 2, animals survived one but not two challenges and had Ag but no Ab. In group 3, animals survived two challenges at the lower drug level but not the higher. All animals in group 4 succumbed to one challenge.