Keiko Yumura

Aggressive natural killer cell leukaemia/lymphoma: report of four cases and review of the literature POSSIBLE EXISTENCE OF A NEW CLINICAL ENTITY ORIGINATING FROM THE THIRD LINEAGE OF LYMPHOID CELLS

The morphologic, immunologic, genotypic and functional properties of peripheral blood and bone marrow cells or cultured cells from four patients with a clinically aggressive non‐T, non‐B natural killer cell leukaemia/lymphoma (ANKL/L) are described. The leukaemic cells possessed medium to large granules in the cytoplasm, antigens against CD38, CD2, OKIa1 and NKH‐1 (CD56) monoclonal antibodies on their cell‐surface, and also showed natural killer (NK) activity. In addition, these ANKL/L belonged to neither T‐ nor B‐cell lineage, proved by studying clonal gene rearrangement for the Tβ, Tγ and Tδ receptors, and immunoglobulin.

Remarkable Depression of CD4+2H4+ T Cells in Severe Chronic Active Epstein‐Barr Virus Infection

In order to better understand the features of chronic active Epstein‐Barr (EB) vims infection, we employed two‐colour immunofluorescence staining with monoclonal antibodies and flow cytometry analysis to study the lymphocyte phenotypes of two patients with severe symptoms of this disorder as well as four patients with mild symptoms. We found an increased number of activated T cells, as characterized by CD4+ la+, CD8+Ia+, or CD4+Tac+ phenotypes, and a markedly decreased CD4+2H4+ T cell subpopulation, previously characterized as a suppressor‐inducer subset, in the patients with severe symptoms. In contrast, the four patients with mild symptoms showed only a slightly elevated number of activated T cells and a normal CD4+2H4+/CD4+ ratio. These phenotypic differences may suggesst heterogeneity in this disorder. Also, a failure in ihe suppressor‐inducer population could contribute to changes in the host‐virus relationship and the degree of the decrease in this population may correlate directly with ihe severity of the disease.

Concomitant rearrangements of T-cell β- and γ-chain genes in childhood T-lineage leukemia/lymphoma☆

Abstract Similar to the immunoglobulin (Ig) gene rearrangements in B-lineage cells, identification of T-cell receptor (TCR) gene rearrangements is a novel clonal marker and necessary to establish a T-cell lineage. The function of T-cell γ-chain (Tγ) gene is still unknown, but because of its shared properties with T-cell α-chain (Tα) and Tβ genes, we analysed Tγ gene organization in 10 patients with T-lineage leukemia/lymphoma as well as in non-T-lineage leukemias. All 10 cases of T-lineage leukemia/lymphoma, whose phenotypes were different, demonstrated Tγ gene rearrangements as well as Tβ gene rearrangements. In contrast, among the non-T-lineage leukemias, the emergence of Tβ and/or Tγ gene rearrangements was varied. Based on these findings, concomitant rearrangements of Tβ and Tγ genes are characteristic in childhood T-lineage leukemia/lymphoma regardless of their phenotypic differences. Furthermore, no obvious developmental hierarchy was observed between Tβ and Tγ gene arrangements in these leukemia/lymphoma cells.

Immunoglobulin and T-Cell Receptor Gene Rearrangement in Leukemia and Lymphoma

More precise identification of the cell lineage of given malignant cells and determination of the different stages of development within that lineage may ultimately be important for achieving more specific and effective treatment. Therefore, we have studied the phenotypes and genotypes of childhood leukemia/lymphoma cells by using a panel of monoclonal antibodies and Southern blot analysis. Here we report the results of studies on 68 patients with childhood leukemia or lymphoma.