title: Phenotypic analysis of hairy cell leukemia: "variant" cases express the interleukin-2 receptor beta chain, but not the alpha chain (CD25).
abstract: Hairy cell leukemia (HCL) is a B-cell chronic lymphoproliferative disorder in which the pathologic cells show a strong expression of CD25 (interleukin-2 [IL-2] receptor alpha chain or p55). "Variant" cases of HCL, characterized by hyperleukocytosis, neoplastic elements with a prominent nucleolus and a higher nucleo/cytoplasmic ratio, and an easily obtained bone marrow aspirate, lack surface CD25 determinants. Limited information is available on the expression of the IL-2 receptor beta chain (p75) on normal and neoplastic B cells. In this study, we have assessed by immunofluorescence and mRNA analysis the presence of the IL-2 receptor alpha and beta chains on 12 cases of classic HCL, as well as on 3 variant cases. The results obtained show that, while the alpha chain of the IL-2 receptor is present only on classic HCL, the IL-2 receptor beta chain (p75) is expressed on both the classic and variant form. Unlike hairy cells, only 8 of the 15 B-cell chronic lymphocytic leukemia cases tested showed a weak expression of the p75 antigen on a small proportion of cells. Purified B lymphocytes from normal healthy controls, as well as Epstein-Barr virus-transformed lymphoblastoid cell lines, showed a weak staining for the p75 determinant, while being CD25-. The results of this study suggest that the expression of the alpha and beta chains of the IL-2 receptor appears to be upregulated or downregulated during the process of B-cell-lineage activation and differentiation.
authors.affiliation: Instituto Nazionale per la Ricerca sul Cancro, Genova, Italy.
authors.forename: D
authors.initials: D
authors.lastname: de Totero
authors.forename: P L
authors.initials: PL
authors.lastname: Tazzari
authors.forename: F
authors.initials: F
authors.lastname: Lauria
authors.forename: D
authors.initials: D
authors.lastname: Raspadori
authors.forename: P F
authors.initials: PF
authors.lastname: di Celle
authors.forename: A
authors.initials: A
authors.lastname: Carbone
authors.forename: M
authors.initials: M
authors.lastname: Gobbi
authors.forename: R
authors.initials: R
authors.lastname: Foa
mesh_terms: D000328:Adult; D000368:Aged; D000911:Antibodies, Monoclonal; D001402:B-Lymphocytes / Q000276:immunology* / Q000473:pathology; D001483:Base Sequence; D002462:Cell Membrane / Q000276:immunology; D005260:Female; D005455:Fluorescent Antibody Technique; D006801:Humans; D007943:Leukemia, Hairy Cell / Q000276:immunology* / Q000473:pathology; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000276:immunology; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D010641:Phenotype; D012333:RNA, Messenger / Q000032:analysis; D015375:Receptors, Interleukin-2 / Q000032:analysis* / Q000737:chemistry / Q000235:genetics
chemical_list: D000911:Antibodies, Monoclonal; D012333:RNA, Messenger; D015375:Receptors, Interleukin-2