CD4 and acute respiratory distress syndrome: In summary, during E. coli and LPS-induced ALI, splenic CD4+CHAT+ cells can synthesize ACh, which activates α7 nAChR in CD11b+ cells (monocytes and neutrophils) to elicit phosphorylation of AKT1, stabilizes α7 nAChR+CD11b+ cells in the spleen and decreases recruitment of α7 nAChR+CD11b+ cells towards the injured lung.