title: Polyclonal B-cell lymphocytosis with features resembling hairy cell leukemia-Japanese variant.
abstract: Polyclonal B lymphocytosis was found in four patients having clinical and hematologic features resembling those of hairy cell leukemia (HCL). All four patients were women between 37 and 67 years of age. Three patients had splenomegaly. Lymphadenopthy was absent or slight. Persistent lymphocytosis was seen in all the patients, and anemia and/or thrombopenia was observed in three of the patients. Abnormal lymphocytes have long microvilli and prominent membranous ruffles on their surfaces. Bone marrow aspirates and biopsy specimens showed increased numbers of abnormal lymphocytes with round nuclei and abundant pale cytoplasm. Although these findings were similar to those of HCL, studies of Ig gene rearrangements and expression showed the polyclonal proliferation of B cells. We called this new disease hairy B-cell lymphoproliferative disorder (HBLD). All four patients exhibited a polyclonal increase in serum IgG. The morphology of the cells in HBLD was more similar to that of leukemia cells of a variant form of HCL (HCL-Japanese variant) than to typical HCL cells. The surface IgG+, CD5-, CD11c+, CD22+, CD24-, CD25- phenotype and the weak tartrate-resistant acid phosphatase activity in the cells were identical to those of HCL cells of the Japanese variant. Our findings suggest that the B cells in HBLD are the nonmalignant counterpart of leukemic B cells in HCL-Japanese variant.
authors.affiliation: Department of Hematology and Oncology, Osaka University Medical School, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Machii
authors.forename: M
authors.initials: M
authors.lastname: Yamaguchi
authors.forename: R
authors.initials: R
authors.lastname: Inoue
authors.forename: Y
authors.initials: Y
authors.lastname: Tokumine
authors.forename: H
authors.initials: H
authors.lastname: Kuratsune
authors.forename: H
authors.initials: H
authors.lastname: Nagai
authors.forename: S
authors.initials: S
authors.lastname: Fukuda
authors.forename: K
authors.initials: K
authors.lastname: Furuyama
authors.forename: O
authors.initials: O
authors.lastname: Yamada
authors.forename: Y
authors.initials: Y
authors.lastname: Yahata
authors.forename: T
authors.initials: T
authors.lastname: Kitani
mesh_terms: D000328:Adult; D000368:Aged; D001402:B-Lymphocytes / Q000276:immunology / Q000378:metabolism / Q000473:pathology*; D001853:Bone Marrow / Q000473:pathology; D002999:Clone Cells; D005260:Female; D015322:Gene Rearrangement, B-Lymphocyte; D015329:Gene Rearrangement, T-Lymphocyte; D006684:HLA-DR Antigens / Q000235:genetics; D006801:Humans; D007143:Immunoglobulin Heavy Chains / Q000235:genetics; D007147:Immunoglobulin Light Chains / Q000096:biosynthesis; D007145:Immunoglobulin kappa-Chains / Q000235:genetics; D016130:Immunophenotyping; D007564:Japan; D007943:Leukemia, Hairy Cell / Q000235:genetics / Q000276:immunology / Q000473:pathology*; D008218:Lymphocytosis / Q000235:genetics / Q000276:immunology / Q000473:pathology*; D008875:Middle Aged; D010641:Phenotype; D011947:Receptors, Antigen, B-Cell / Q000096:biosynthesis
chemical_list: D006684:HLA-DR Antigens; D007143:Immunoglobulin Heavy Chains; D007147:Immunoglobulin Light Chains; D007145:Immunoglobulin kappa-Chains; D011947:Receptors, Antigen, B-Cell