Keisei Kawa-Ha

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.

Clonal lymphoproliferation following chronic active Epstein-Barr virus infection and hypersensitivity to mosquito bites.

In order to elucidate the possibility of lymphoproliferation in cases of chronic active Epstein‐Barr virus infection (CAEBV), to clarify the clonality and genotype of proliferating lymphocytes, and to search for the factors that induce lymphoproliferation, we studied 11 cases of CAEBV, using genetical and immunological techniques.

Hypersensitivity to Mosquito Bites Conceals Clonal Lymphoproliferation of Epstein-Barr Viral DNA-positive Natural Killer Cells

In order to clarify the relationship between Epstein‐Barr (EB) virus and hypersensitivity to mosquito bites (HMB), and to search for the mechanism which induces EB virus‐associated lymphoproliferative diseases, we investigated patients with HMB, using hematological, immunological and virological techniques. Among 5 cases of HMB, CD56+ cells had proliferated and CD3+ cells were diminished in 4 cases. Although anti‐EB virus antibody titers were not consistent with chronic active EB virus infection, EB viral DNA was detected in the peripheral blood mononuclear cells in all 5 cases. Moreover, EB viral DNA‐positive cells had proliferated monoclonally in 4 cases, and hiclonally in 1 case. It was proved that most of the EB viral DNA existed in natural killer (NK) cells through polymerase chain reaction analysis. These findings suggest that the basis of HMB may be clonal lymphoproliferation of EB viral DNA‐positive NK cells and this hematological abnormality may induce the characteristic symptoms of HMB. In some cases, the proliferating NK cells can metamorphose into leukemic cells, and hemophagocytic syndrome, which has been assumed to be a complication of HMB, may then occur.

Mixed phenotype of blasts in acute megakaryocytic leukaemia and transient abnormal myelopoiesis in Down's syndrome

Blasts from eight cases with acute megakaryoblastic leukaemia (AMKL) and seven with transient abnormal myelopoiesis in Downs syndrome (TAM) were investigated to clarify their phenotypic characteristics. CD41 and CD7 were the most frequently expressed in both disorders. CD41 was positive in six TAM and five AMKL cases, and CD7 was positive in five TAM and five AMKL cases, respectively. CD33 was detected in four TAM and five AMKL cases. Other myeloid‐lineage associated antigens such as CD13 and CD11b could not be found in TAM but were expressed in five AMKL cases. Interestingly, CD56, a neural adhesion molecule, was expressed in three of four TAM and one of five AMKL cases. Cytoplasmic CD3 antigen was also noted in three of five examined cases.

Clinical significance of CD7-positive stem cell leukemia : a distinct subtype of mixed lineage leukemia

Ten leukemia cases with mixed phenotype were investigated in terms of clinical characteristics and cellular origin. Three patients were infants and six patients were older children. Six of them had a high leukocyte count and a mediastinal mass was found in three cases. All but one showed hepatosplenomegaly and/or lymphoadenopathy. In spite of intensive chemotherapy, most of them responded poorly. Cytochemical analysis of their leukemic cells revealed a low percentage of positivity for myeloperoxidase reactivity (< 25%) in two cases and electron microscopic platelet peroxidase reactivity was found in one of three analyzed cases. Phenotypically, these cells all expressed CD7, and other T‐lineage‐associated, B‐lineage‐associated, and/or myeloid‐associated antigens were also detected to some extent. In addition, three cases expressed CD41 and one case expressed CD56. The T‐cell receptor (TCR) genes and immunoglobulin gene were in the germline configuration in seven cases. In three rearranged cases two showed only the TCR‐δ gene rearrangement, and one had both TCR‐γ and δ gene rearrangements. Cell culture studies with 12–0‐tetradecanoyl‐phorbol‐13‐acetate (TPA) revealed differentiation to the T‐lineage in two cases and to a myeloid lineage in one case. Megakaryocytic differentiation was detected in two cases in culture without TPA. These results suggest that the cells from these cases arose from stem cells capable of both lymphoid and nonlymphoid differentiation. Although the cells were heterogeneous with regard to their potency of differentiation, they have similar clinical characteristics. Because of poor prognosis, it is important to identify this type of leukemia, and allogenic or autologous bone marrow transplantation should be considered. Cancer 68:2273–2280, 1991.

The detection of clonal proliferation in granular lymphocyte-proliferative disorders of natural killer cell lineage.

Summary. The clonal proliferation of large granular lymphocytes can be detected in patients with T‐cell‐lineage granular lymphocyte‐proliferative disorders (T‐GLPD) by Southern blotting T‐cell receptor genes. However, this cannot be applied to patients with natural killer‐cell‐lineage GLPD (NK‐GLPD) as it lacks a clonal marker. We therefore investigated the use of two other diagnostic techniques in evaluating clonal proliferation in Japanese patients with NK‐GLPD (n = 4) and T‐GLPD (n=3) by chromosomal analysis of peripheral blood mononuclear cells (PBMC) stimulated with either interleukin‐2 or phytohaemaggluti‐nin, and Epstein‐Barr viral (EBV) genomic DNA analysis. Chromosomal analysis revealed abnormal karyotypes in the PBMC of three of four patients with NK‐GLPD, whereas EBV analysis showed a monoclonal terminal configuration in the PBMC in the fourth patient. Southern blots revealed rearrangements of the TCR genes in all three patients with T‐GLPD but in none of those with NK‐GLPD. It is suggested that these methods may be useful in detecting the abnormal proliferation of large granular lymphocytes in NK‐GLPD.

Isolation of human herpesvirus 7 from a child with symptoms mimicking chronic Epstein‐Barr virus infection

Summary. Human herpesvirus‐7 (HHV‐7), which is a newly identified human herpesvirus with an unknown pathologic role, was isolated from a 5‐year‐old boy suffering from fever, hepatosplenomegaly and pancytopenia. Although the clinical course was similar to that of chronic active Epstein‐Barr virus infection, no viruses other than HHV‐7 were isolated. This finding raises the possibility that HHV‐7 played a pathogenic role in the present patient.

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.

Phenotypic Characteristics of Acute Megakaryocytic Leukemia and Transient Abnormal Myelopoiesis

By immunophenotyping and ultrastructural cytochemistry, the disorders involving megakaryocytic lineage cells have been clarified. These disorders are termed acute megakaryocytic leukemia (AMKL) and transient abnormal myelopoiesis (TAM). The characteristics of blasts in these disorders have been extensively investigated from various standpoints including cytochemistry, cytogenetics, ultrastructure and in vitro-colony differentiation. The target cells of AMKL and TAM are immature cells close to stem cells which are capable of differentiating into lineage cells such as megakaryocytes, erythrocytes and myeloid cells. Phenotypically, these blasts frequently express antigens appearing at an early stage in the hematopoietic differentiation pathway. They thus often emerge as mixed phenotypes as seen in mixed lineage leukemia of immature cell origin.

Increased expression of the multidrug-resistance gene in undifferentiated sarcoma

We analyzed multidrug‐resistance gene (mdr1 gene) expression in a patient with undifferentiated sarcoma of the liver using the cloned cDNA for the mdr1 gene. Tissue samples were available at the time of initial diagnosis and of two intracranial relapses after chemotherapy with a regimen including doxorubicin and teniposide. The level of mdr1 gene expression was increased sevenfold in the intracranial tumor at the time of first relapse and 11‐fold at the second relapse. This case may be an example of acquired multidrug resistance associated with overexpression of the mdr1 gene.