Comparison of the expression of CD15, CD18, and CD177 by neutrophils from MPD patients, healthy subjects, and healthy subjects given G-CSF. Neutrophil expression of CD15, CD18, and CD177 was analyzed by flow cytometry in 24 MPD patients and 43 healthy subjects. The results are expressed as a percent of neutrophils that were reactive with each antibody. The expression of CD15 and CD18 was significantly greater in MPD neutrophils compared to those from healthy subjects, but there was no difference in the expression of CD15 and CD18 between neutrophils from healthy subjects given G-CSF and those who were not. The expression of CD177 was increased in G-CSF-mobilized neutrophils compared to unmobilized healthy subject and MPD neutrophils, but there was no difference in CD177 expression between MPD and unmobilized healthy subject neutrophils.