Clonal cell surface structures related to differentiation, activation and homing in B-cell chronic lymphocytic leukemia and monoclonal lymphocytosis of undetermined significance

Authors

  • Eva Kimby,

    1. Department of Medicine, Division of Hematology, Danderyd Hospital, Stockholm, Sweden
    2. Immunologic Research Laboratory, Division of Hematology, Karolinska Hospital, Stockholm, Sweden
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  • Håkan Mellstedt,

    Corresponding author
    1. Department of Oncology (Radiumhemmet), Division of Hematology, Karolinska Hospital, Stockholm, Sweden
    2. Immunologic Research Laboratory, Division of Hematology, Karolinska Hospital, Stockholm, Sweden
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  • Magnus Björkholm,

    1. Immunologic Research Laboratory, Division of Hematology, Karolinska Hospital, Stockholm, Sweden
    2. Department of Medicine, Division of Hematology, Karolinska Hospital, Stockholm, Sweden
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  • Göran Holm

    1. Department of Medicine, Division of Hematology, Danderyd Hospital, Stockholm, Sweden
    2. Immunologic Research Laboratory, Division of Hematology, Karolinska Hospital, Stockholm, Sweden
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Department of Oncology (Radiumhemmet) Karolinska Hospital S-104 01 Stockholm Sweden

Abstract

Cell surface structures related to differentiation, activation and “homing” were identified on the leukemic cell clone in blood of 64 patients with a monoclonal B-cell lymphoproliferative disorder. Patients were selected with regard to clinical signs and symptoms of the disease. 39 patients had progressive chronic lymphocytic leukemia of B-cell type (B-CLL): 16 with lymph node enlargement and 14 with progressive lymphocytosis as the most prominent symptom, respectively. 1 patient had an isolated splenomegaly and 8 had symptoms from enlarged lymph nodes, lymphocytosis and/or splenomegaly. 25 patients had an isolated monoclonal B-cell lymphocytosis in blood and bone-marrow but no other signs or symptoms of the disease. The lymphocytosis in these patients was considered to be of “undetermined significance” and the term B-cell lymphocytosis of undetermined significance (B-MLUS) was used. Patients with a prominent lymphadenopathy and/or splenomegaly had CD22+ leukemic cells while in patients with a progressive lymphocytosis the B-cell clone expressed Leu-8. Thus, CD22 might be related to the homing capacity of B lymphocytes for lymphnodes and spleen, while Leu-8 might define a circulating B-cell subset. In B-MLUS about 50% of the monoclonal B cells co-expressed Leu8 which is consistent with a more differentiated phenotype compared to B-CLL with progressive lymphocytosis. The CD22 expression was mostly low in B-MLUS although a few patients showed high values. The expression of receptors for growth factors (CD23, CD25, CD71) was higher in B-CLL compared to B-MLUS patients (p < 0.001), which is consistent with a difference in lymphocyte activation stage and/or response to growth factors.

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