CD200 Flow Cytometric Assessment and Semiquantitative Immunohistochemical Staining Distinguishes Hairy Cell Leukemia From Hairy Cell Leukemia-Variant and Other B-Cell Lymphoproliferative Disorders

Abstract

OBJECTIVES: To evaluate CD200 expression in B-cell proliferative disorders. METHODS: We analyzed 180 recent specimens of B-cell neoplasms for CD200 expression by flow cytometric immunophenotypic analysis, which is better able to assess relative intensity of staining than immunohistochemical staining. RESULTS: We found that hairy cell leukemia exhibits a high level of staining for CD200 in comparison to other B-cell lymphoproliferative disorders, including hairy cell leukemia-variant (HCL-V), marginal zone lymphoma, and lymphoplasmacytic lymphoma. We confirmed this observation by semiquantitative immunohistochemical staining. CONCLUSIONS: Assessment of the CD200 expression level is helpful to distinguish HCL from HCL-V and other B-cell lymphoproliferative disorders and in the differential diagnosis of B-cell neoplasms in general.