Chronic Myelomonocytic Leukemia Monocytes Uniformly Display a Population of Monocytes With CD11c Underexpression

Abstract

A distinct heterogeneous population of monocytic cells with underexpression of CD11c was identified in all these cases. CD11c underexpression was independent of other aberrancies, including HLA-DR underexpression (n = 14), aberrant CD56 expression (n = 11), and underexpression of CD33, CD38, and CD14 (n = 6, 5, and 5, respectively), supporting the utility of CD11c expression status on monocytes in establishing a CMML diagnosis.

Application of immunophenotypic analysis in distinguishing chronic myelomonocytic leukemia from reactive monocytosis

“…In CMML, monocytes, granulocytes, and blasts exhibit aberrant antigen expression. (12)(13)(14)16,17) Similar abnormalities may be seen in a small subset of reactive monocytosis cases. (2) Most of the previous studies evaluating CMML have primarily used normal bone marrow for comparison.…”

“…Twelve of 34 (35%) and 16 of 34 (47%) CMML cases exhibited two or more phenotypic alterations in monocytes and in granulocytes, respectively (Table ). We found that CD56 expression was the most common aberrancy in CMML, which has been described in several studies . However, CD56 expression on monocytes is not specific for CMML as it can be present in reactive monocytes (inflammatory responses), post‐chemotherapy hematopoietic regeneration, Down syndrome, myeloproliferative disorders, and other myelodysplastic/myeloproliferative disorders.…”

“…We found that CD56 expression was the most common aberrancy in CMML, which has been described in several studies. (12,13,15,17) However, CD56 expression on monocytes is not specific for CMML as it can be present in reactive monocytes (inflammatory responses), post-chemotherapy hematopoietic regeneration, Down syndrome, myeloproliferative disorders, and other myelodysplastic/ myeloproliferative disorders. Though CD56 expression on monocytes must be interpreted cautiously and in the context of other clinical and pathologic findings, highlevel CD56 expression in the majority of monocytes suggests CMML over reactive monocytosis.…”

“…In CMML, monocytes, granulocytes, and blasts exhibit aberrant antigen expression . Similar abnormalities may be seen in a small subset of reactive monocytosis cases .…”

“…(6)(7)(8)(9) Standardization of flow cytometry as part of an integrated diagnosis of MDS has been proposed by the international consortium and the European LeukemiaNet Working group. (10,11) Though several studies have demonstrated immunophenotypic changes in CMML by flow cytometry, (12)(13)(14)(15)(16) less is known of the role of flow cytometry in diagnosis of CMML and no consensus exists on which diagnostic parameters are the most appropriate.…”