Fig. 4

Macrophage infiltration in red blood cell (RBC) transfusion-associated necrotizing enterocolitis (NEC). a Representative scatter plots from control and anemic-transfused mice. The CD11b (+) myeloid cell fraction was enriched in anemic and anemic-transfused mice, and clustered into discrete F4/80 (hi) and F4/80 (mid) populations. The F4/80 (mid) macrophage population in anemic and anemic-transfused mice was CD115 (+) and Ly6C (+). b Fluorescence photomicrographs (ileum, colon; magnification ×800) showed scattered F4/80 (+) macrophages (green, open arrows) in naive and transfusion control. Numerous Ly6C (+) cells (red, solid arrows) were also seen in anemic and anemic-transfused intestine. Scale bar =50 µm. Scatter plots below summarize the number of Ly6C (+) and F4/80 (+) cells in each group. Kruskal–Wallis H test with Dunn’s post test, ^†P < 0.001 vs. naive control. Data represent 10 mice per group. c Scatter bar diagrams summarize LPS-stimulated inflammatory cytokine expression in the F4/80 (hi) and F4/80 (mid) cell populations in vitro, measured by reverse transcriptase-quantitative polymerase chain reaction (RT-qPCR). N = 8 mice per group; Mann–Whitney U test, *P < 0.05, **P < 0.01