Neutrophil CD177 Flow Cytometric Expression as a Potential Myeloid Marker

Introduction: A specific clonality marker, may enhance diagnosis of myeloid neoplasms, particularly in challenging cases. Neutrophil CD177, being exclusive to the granulocytic series, could represent a good potential marker. Our aim in this study was to explore this assumption. Methods: 213 subjects with benign and neoplastic' myeloid disorders were included in this study. Peripheral blood neutrophils were analyzed by flow cytometry (FC) for CD177+% and mean fluorescent intensity (MFI). Results: CD177 showed 2 expression patterns; single& bimodal. Neutrophil CD177+ MFI was significantly higher in Ph- negative c-MPNs (2.9-37.4; median 14.1), compared to controls (0.8-20.5; median 8.8). No significant difference in either CD177% or MFI was observed between Polycythemia Vera (PV) and Essential Thrombocythemia (ET) groups. The PV group showed a significantly higher, CD177 MFI compared to SE and control groups (4.8-37.4; median 16.5, 1.58-25.7; median 5.81, 0.85-20.5; median 8.8 respectively). Similarly, the ET group had a significantly higher CD177+ MFI compared to controls (2.9- 34.5; median 13.4 versus 0.85-20.5; median 8.8 respectively). No significant difference in CD177+ neutrophil % or MFI was observed in MDS patients compared to controls. No significant correlation was detected between CD177+% and MIF, nor with the JAK2 V617F allele burden in JAK-2+ cases. A high specificity of CD177 MFI was only observed in; Ph-negative c-MPNs (93%) & in differentiating PV from SE (85%); at a cutoff, of 20 p.d.u. Conclusion: The CD177 expression is suggested as a good potential marker in Ph-negative MPNs, particularly in differentiating PV and secondary erythrocytosis