Elastase as a marker for neutrophilic myeloid cells.

The immunohistochemical results obtained with antibodies directed against human neutrophil elastase is described. It was found that neutrophil elastase can be used as a specific marker of cells of the neutrophilic lineage. In normal hematopoietic cell preparations, only promyelocytes and more differentiated myeloid cells stain positive for elastase. In acute or chronic myeloid and myelomonocytic leukemia, the same neutrophil myeloid cells stain positive, whereas neoplastic cells of the monocytoid line are negative. Using elastase in conjunction with other markers, it is possible to differentiate easily the involvement of different cell lines in myeloproliferative diseases.