Figure 2

Frequency of labeled donor cells in circulation. Blood was collected from recipients which were sacrificed at 2 or 24 hours after cell transfusion. The frequency of labeled cells was measured by flow cytometry and the total number of labeled donor cells in recipients' circulation was calculated. The results are shown as percentages of total number of transfused donor cells. In the whole BM cell transfusion experiment (A), the proportion of donor cells at 2 hours post-transfusion was 3.3 ± 0.7% and 4.3 ± 0.7% in control and pneumonia groups, respectively (P = 0.34). However, the ratio of labeled cells in the pneumonia group significantly decreased to 1.8 ± 0.3% at 24 hours (P = 0.01). In the Lin- progenitor cell transfusion model (B), the proportion of labeled progenitor cells in the pneumonia group was significantly higher than control (21.7 ± 2.7% vs. 7.7 ± 0.9%, P = 0.008) at 2 hours. The percentage of donor cells in the circulation in both the control and pneumonia groups decreased after 24 hours and the difference between the two groups was no longer significant at 24 hours post-transfusion. Data is shown as mean ± SE; n = 6 (control group for each timepoint) and n = 7 (pneumonia group for each timepoint). *P < 0.05, **P < 0.01.