Redistribution of myeloperoxidase and elastase in human neutrophil granulocytes

Both myeloperoxidase (MPO) and elastase were found to be redistributed in ethanol-and Bouin-fixed human neutrophil granulocytes. Air-dried and formalin-fixed cells, stained for MPO, appeared with a cytoplasmic fluorescence and unstained nuclei. In elastase air-dried cells a faint perinuclear staining was also detected. Otherwise the redistribution pattern was very similar for MPO and elastase. It was found that both elastase and MPO were most efficiently extracted with Bouin's fixative. A discontinuous fluorescence was seen especially for MPO in ethanol-fixed cells. Nuclear membrane staining was verified with laser scan microscopy. This technique also visualized a scattered fluorescence in the nuclear matrix for MPO.