title: HLA-DO. A useful marker to distinguish florid follicular hyperplasia from follicular lymphoma by flow cytometry.
abstract: HLA-DO expression is regulated during B-cell development and activation. To determine whether the level of HLA-DO expression is a helpful marker in the differential diagnosis between florid follicular hyperplasia and follicular lymphoma, we analyzed single-cell suspensions from 29 lymph node specimens by 4-color flow cytometry. Of the 29 specimens, 7 were from patients with florid follicular hyperplasia, in which the clonality of the germinal center B cells (GCBCs) was indeterminate by flow cytometric immunophenotyping. The remaining 22 cases were follicular lymphomas; neoplastic cells in 2 of these cases lacked expression of surface immunoglobulin light chains. The level of HLA-DO expression in the reactive CD10+ GCBCs in florid follicular hyperplasia was markedly down-regulated compared with the CD10- polytypic B cells of the same specimens. In contrast, the level of HLA-DO expression in the CD10+ neoplastic cells in all cases of follicular lymphomas was similar to that of the CD10- polytypic B cells, thus higher than the reactive CD10+ GCBCs. This difference was confirmed by immunohistochemical staining. Our results suggest that HLA-DO is a useful marker to differentiate florid follicular hyperplasia from follicular lymphoma by flow cytometry, particularly when clonality of the CD10+ B cells is in question.
authors.affiliation: Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA, USA.
authors.forename: Xinjian
authors.initials: X
authors.lastname: Chen
authors.forename: Peter E
authors.initials: PE
authors.lastname: Jensen
authors.forename: Shiyong
authors.initials: S
authors.lastname: Li
mesh_terms: D001402:B-Lymphocytes / Q000473:pathology*; D014408:Biomarkers, Tumor / Q000032:analysis*; D003937:Diagnosis, Differential; D005434:Flow Cytometry; D006681:HLA-D Antigens / Q000032:analysis*; D006965:Hyperplasia; D007150:Immunohistochemistry; D016130:Immunophenotyping; D008198:Lymph Nodes / Q000473:pathology; D008224:Lymphoma, Follicular / Q000737:chemistry / Q000175:diagnosis* / Q000276:immunology; D015260:Neprilysin / Q000032:analysis
chemical_list: D014408:Biomarkers, Tumor; D006681:HLA-D Antigens; C046148:HLA-DO antigens; D015260:Neprilysin