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We report here a case of "splenic lymphoma with villous lymphocytes" (SLVL) which exhibited both B- and T-cell phenotypes and genotypes. The patient was a 73-year-old man. Physical examination revealed splenomegaly and lymphadenopathy. The white blood cell count was 55.2 x 10(9)/L with 70.5% atypical lymphocytes, having cytoplasmic villi, characteristic of SLVL. The atypical cells infiltrated both the red and white pulps. Immunological analysis of the peripheral leukocytes showed both B- and T-cell phenotypes (CD5,CD11c,CD19,CD20,HLA-DR, SmIgM and lambda positive). DNA analysis revealed a dual rearrangement of the immunoglobulin heavy chain gene and T-cell receptor beta gene. SLVL has been identified as a B-cell leukemia with a relatively benign clinical course. This case had both B- and T-cell pheno- and genotypes with a progressive course. To the best of our knowledge, no case of SLVL with dual genotypes has ever been reported.

Two new myeloid cell lines (K051 and K052) were established from a patient with multilineage CD7-positive acute leukemia. The K051 and K052 were established from the patient's bone marrow cells at diagnosis and at relapse, respectively. The K051 cell expressed myeloid- associated antigens (CD13 and CD33), a platelet-associated antigen (CD41), and an erythroid antigen (glycophorin A). The K052 cell expressed myeloid-associated antigens (CD13, CD14, and CD33), lymphoid markers (CD2, CD5, and CD7), and HLA-DR. Chromosome analysis of both cell lines showed a 17p- chromosome. Both cell lines were investigated for aberrations of the p53 gene and the N-ras gene. A p53 mutation detected in both cell lines consisted of a C-->T substitution in codon 248. An N-ras mutation detected only in the K052 cell consisted of a G-- >C substitution in codon 13. Expression of the multidrug resistance gene (MDR1) was also investigated by the semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR). MDR1-mRNA was more highly expressed by the K052 cell than the K051 cell, being equivalent to that in HEL cells. The functional MDR1-protein against vincristine was also observed, and its function was inhibited by verapamile and Cyclosporin A. The K052 cells were capable of phenotypic or morphologic differentiation after being incubated with granulocyte colony- stimulating factor, interleukin-2, phorbol 12-myristate 13-acetate, or 1,25-dihydroxy-vitamin D3. In contrast, the K051 cells responded phenotypically to retinoic acid. Thus, the K051 and K052 cell lines will be useful for investigating the cellular and molecular events in leukemogenesis and differentiation, and the mechanism of expression of the MDR1 gene.

A new B-cell line (VL51) with cytoplasmic villi was established from a female patient with splenic lymphoma with circulating villous lymphocytes (SLVL). The patient exhibited a clinical picture characteristic of SLVL, including massive enlargement of the spleen. Tartrate-resistant acid phosphatase (TRAP)-negative villous lymphocytes were seen in the peripheral blood, bone marrow (BM) and both red and white pulps of the spleen. Monoclonality of the VL51 cell line was confirmed by clonal genotype abnormalities in the immunoglobulin heavy chain (IgH) gene and the T-cell receptor beta (TCR beta) gene. Evidence for commitment of phenotype of the VL51 cell line to the B lineage was also shown by the immunophenotype, including expression of CD10, CD19, CD20 and surface immunoglobins. The VL51 cells were positive for Epstein-Barr virus nuclear antigen (EBNA). The VL51 cell line is the first SLVL cell line to be established, and it is expected to be useful in clarifying the leukemogenesis of SLVL.