MRC1 and acute respiratory distress syndrome: Conversely, CD206+ lung macrophages were scarce in ALI mice, whereas Nor-CM and Hypo-CM significantly increased CD206+ lung macrophages (Figure 8A,C), which was consistent with the results of flow cytometry in Figure 6D. Moreover, the ratio of free ACs to CD206+ macrophages-associated ACs, indicative of defective efferocytosis of macrophages, was highest in lung tissues of ALI models.