title: CD5-negative chronic lymphocytic leukemia with indolent clinical course and autoimmune thrombocytopenia, successfully treated with rituximab.
abstract: A 59-year-old male with lymphocytosis and thrombocytopenia was asymptomatic without lymphadenopathy or hepatosplenomegaly over 10 years. He was admitted to our hospital because his thrombocytopenia had worsened. The clonal lymphocytes appeared as regular small mature lymphocytes on blood films, and bone marrow biopsy showed diffuse infiltration of mature lymphocytes. However, megakaryocytes also presented. The immunophenotypic analysis by flow cytometry revealed that the lymphocytes were positive for CD19, CD20, CD22, and surface membrane immunoglobulin (SmIg) M and D-lambda and were negative for CD5, CD10, CD11c, CD23, and other lineage markers. Expression levels of CD20 and SmIg were strong. The markers were consistent with CD5- CLL with autoimmune thrombocytopenia. He received rituximab, and a rapid decrease of lymphocytes with concomitant increase of platelets was observed. A few cases of CD5- CLL with a stable clinical course have been reported, thought to be B lymphocytosis of undetermined significance (MLUS). This is the first report of CD5- CLL with indolent clinical course associated with autoimmune thrombocytopenia, successfully treated with rituximab.
authors.affiliation: Division of Hematology and Oncology, Department of Medicine, Kyoto Prefectural University of Medicine, Kyoto, Japan. okamotom@koto.kpu-m.ac.jp
authors.forename: Masashi
authors.initials: M
authors.lastname: Okamoto
authors.forename: Sonoko
authors.initials: S
authors.lastname: Nakano
authors.forename: Kyoko
authors.initials: K
authors.lastname: Namura
authors.forename: Noriko
authors.initials: N
authors.lastname: Yamada
authors.forename: Ryo
authors.initials: R
authors.lastname: Uchida
authors.forename: Shin-Ichi
authors.initials: S
authors.lastname: Fuchida
authors.forename: Akira
authors.initials: A
authors.lastname: Okano
authors.forename: Naoya
authors.initials: N
authors.lastname: Ochiai
authors.forename: Chihiro
authors.initials: C
authors.lastname: Shimazaki
mesh_terms: D000911:Antibodies, Monoclonal / Q000627:therapeutic use*; D058846:Antibodies, Monoclonal, Murine-Derived; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D015415:Biomarkers / Q000032:analysis; D018956:CD5 Antigens / Q000032:analysis* / Q000276:immunology; D005434:Flow Cytometry; D006801:Humans; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000150:complications / Q000188:drug therapy* / Q000276:immunology; D008297:Male; D008875:Middle Aged; D016553:Purpura, Thrombocytopenic, Idiopathic / Q000150:complications* / Q000276:immunology; D000069283:Rituximab; D016896:Treatment Outcome
chemical_list: D000911:Antibodies, Monoclonal; D058846:Antibodies, Monoclonal, Murine-Derived; D000970:Antineoplastic Agents; D015415:Biomarkers; D018956:CD5 Antigens; D000069283:Rituximab