Immunocytochemistry for annexin A1. (A) Neutrophils in blood labeled for annexin A1; monocytes, lymphocytes and platelets are unlabeled. Bar = 10 μm. (B) Bronchoalveolar lavage fluid (BALF); Annexin A1 labeling in the cytoplasm of large foamy macrophages, but not in other macrophages. Bar = 10 μm. (C) BALF; neutrophils are rare in normal BALF but those present are labeled for annexin A1. Bar = 10 μm.