Effect of immunosuppression and amphotericin B on Aspergillus antigenemia in an experimental model.

A modified enzyme-linked immunosorbent assay (ELISA) for crude carbohydrate antigen was used to evaluate the kinetics of aspergillus antigenemia and to determine the effect of therapy on circulating antigen levels in an experimental model. The ELISA was rapid, simple to perform, and able to detect less than 10 ng of antigen/mL of serum. The model was also used to evaluate the effect of temporary and persistent immunosuppression on experimental disease. Antigen levels rose progressively in untreated control rabbits; all 15 animals had significant antigenemia. Treated animals had markedly reduced antigen levels, but nine of 13 rabbits had detectable antigen after 72 h of therapy, a result that correlated with persistent disease. Therapy begun 24 h after challenge in temporarily immunosuppressed animals was more likely to sterilize tissues than was therapy begun 48 h after challenge. Therapy in persistently immunosuppressed rabbits was less effective and may require improved antifungal regimens to be successful.