[1412] Aberrant Expression of CD56 on Granulocytes and Monocytes in Myeloproliferative Neoplasm and Myelodysplastic Syndrome

Ping Gong, Fernanda Metrebian, Alina Dulau-Florea, Zi-Xuan Wang, Renu Bajaj, Stephen C Peiper, Jerald Z Gong. Thomas Jefferson University Hospital, Philadelphia, PA; Academia Nacional de Medicina, Buenos Aires, Argentina

Background: CD56 is a cell adhesion molecule normally expressed in neural tissue and cytotoxic lymphocytes. Aberrant expression of CD56 can be seen in various hematologic malignancies and has been well characterized in acute myeloid leukemia and plasma cell myeloma. However, limited and inconsistent data are available regarding CD56 expression in chronic myeloid neoplasms.
Design: We reviewed CD56 expression in granulocytes and monocytes from 81 cases of myeloproliferative neoplasm (MPN) and 42 cases of myelodysplastic syndrome (MDS). Forty cases of negative staging bone marrow for lymphoma were used as negative controls. CD56 expression on granulocytes and monocytes were analyzed using four-color flow cytometry in all the cases. In addition, CD56 expression on granulocytes was analyzed in patients with series bone marrow samples following treatment and compared with molecular genetic results.
Results: In negative control cases, CD56 expression in granulocytes and monocytes was below 2%. Using 10% as positive threshold, CD56 was positive on granulocytes in 17% and positive on monocytes in 37% of all cases. Aberrant CD56 expression can be seen in all subtypes of MPN (ET 6%, PV 13%, MPN-U 18%, CML 19% to PMF 28%) and in high grade MDS (RCMD 18%, RAEB 27%). CD56 expression was present more frequently in primary myelofibrosis and high grade MDS than other types of MDS and MPD. In general, cases with CD56 expression on granulocytes also had CD56 expression on monocytes, but monocytes usually had higher percentage of CD56. Series specimens were available in 5 cases with positive CD56 expression (2 CML, 1 PMF, 1 PV, 1 NPM-U). CD56 expression correlated with recurrent disease by bone marrow morphology. Where BCR/ABL transcript and bone marrow engraftment studies were available, CD56 reduction correlated with reduced BCR/ABL transcript and/or recipient cell percentage.
Conclusions: Aberrant CD56 expression on granulocytes and monocytes is seen in all subtypes of MPN and high grade MDS. CD56 expression in MPN correlated with bone marrow morphology, BCR/ABL transcript, and bone marrow engraftment study following treatment. Identification of abnormal CD56+ granulocytes and monocytes is helpful in both the initial diagnosis and long-term follow up of patients with MPN and MDS.
Category: Hematopathology

Wednesday, March 21, 2012 9:30 AM

Poster Session V # 220, Wednesday Morning


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