Quantitative real-time PCR of fungal DNA enables the correlation between fungal burden and bioluminescence signals. Mice were immunosuppressed either with cortisone acetate or cyclophosphamide. Two mice from each group were sacrificed at day one and the other two animals from each group at day three after infection. An uninfected mouse was used as a negative control and revealed no signal in the qRT-PCR and is, therefore, omitted from the graph. The bars represent the amount of fungal DNA per microgram of total DNA isolated from the infected tissues with standard deviations from six data points for each individual animal. The two animals investigated for each time point and immunosuppression regimen show the general tendency that at day one after infection the cortisone acetate treated animals show a higher burden than the cyclophosphamide treated animals. Three days after infection, the burden with alive fungal cells seems to stay rather constant under the coticosteroid treatment, but strongly increases under the regimen with cyclophosphamide. The inlet shows the time response of bioluminescence from alive animals with high values for the cortisone acetate treated mice early after infection followed by a decline of the signal intensity at later time points. Under cyclophosphamide regimen the bioluminescence steadily increases. The small photographs above the bars from mice sacrificed at day three show the explanted lungs with an overlay of the emitted light intensities. Numbers above the photographs give the photons/s × cm2. The high bioluminescence from lungs explanted from cyclophosphamide treated animals reflects the higher burden with living fungal cells as determined by the fungal DNA quantification.