We previously showed that CD4+CD25+Foxp3+ Tregs resolve experimental ALI by modulating the following critical prorepair steps: (a) abrogation of macrophage proinflammatory responses (29), (b) augmentation of neutrophil efferocytosis (29), (c) limitation of fibroproliferation (30), and (d) augmentation of alveolar epithelial repair (31). Here, CD4 is linked to acute respiratory distress syndrome.