Principal component analysis uncovers cytomegalovirus-associated NK cell activation in Ph+ leukemia patients treated with dasatinib.

Dasatinib treatment markedly increases the number of large granular lymphocytes (LGLs) in a proportion of Ph+ leukemia patients, which associates with a better prognosis. The lymphocytosis is predominantly observed in cytomegalovirus (CMV)-seropositive patients, yet detectable CMV reactivation exists only in a small fraction of patients. Thus, etiology of the lymphocytosis still remains unclear. Here, we identified NK cells as the dominant LGLs expanding in dasatinib-treated patients, and applied principal component analysis (PCA) to an extensive panel of NK cell markers to explore underlying factors in NK cell activation. PCA displayed phenotypic divergence of NK cells that reflects CMV-associated differentiation and genetic differences, and the divergence was markedly augmented in CMV-seropositive dasatinib-treated patients. Notably, the CMV-associated highly differentiated status of NK cells was already observed at leukemia diagnosis, and was further enhanced after starting dasatinib in virtually all CMV-seropositive patients. Thus, the extensive characterization of NK cells by PCA strongly suggests that CMV is an essential factor in the NK cell activation, which progresses stepwise during leukemia and subsequent dasatinib treatment most likely by subclinical CMV reactivation. This study provides a rationale for the exploitation of CMV-associated NK cell activation for treatment of leukemias.

Leukotriene B4-activated human endothelial cells promote transendothelial neutrophil migration.

We explored the effect of leukotriene B4 (LTB4) on endothelial cells in LTB4-induced transendothelial migration (TEM) of neutrophils as an in vitro model of neutrophil extravasation. Chemotactic response of human neutrophils to LTB4 was significantly lower than that in response to N-formyl-methionyl-leucyl-phenylalanine (fMLP), whereas the extent of TEM in response to LTB4 was significantly higher than that to fMLP. The study on random migration induced by LTB4 and fMLP also showed similar results, which indicated that LTB4 might affect the human umbilical cord vein endothelial cell (HUVEC) barrier. Neutrophil TEM was induced by pretreatment of HUVEC monolayer with LTB4 but not with fMLP. Treatment of endothelial cells by ONO-4057, a LTB4 receptor antagonist, abolished the effect of LTB4 almost completely whereas neutrophils treated with ONO-4057 could transmigrate through HUVEC treated with LTB4. These findings indicated that LTB4 could induce neutrophil TEM by acting on HUVEC.

Random migration of polymorphonuclear leukocytes induced by GM-CSF involving a signal transduction pathway different from that of fMLP.

Granulocyte-macrophage colony-stimulating factor (GM-CSF) induced random migration of human polymorphonuclear leukocytes (PMNs) but not chemotaxis. Chemoattractants such as N-formyl-methionyl-leucyl-phenylalanine (fMLP), leukotriene B4 (LTB4), and interleukin-8 (IL-8) induced both random migration and chemotaxis. Other inflammatory cytokines, including granulocyte colony-stimulating factor (G-CSF), interleukin 1alpha (IL-1alpha), and tumor necrosis factor alpha (TNF-alpha), did not induce either movement. One-minute exposure of PMNs to GM-CSF was sufficient for the induction of random migration, whereas fMLP-induced random migration required continued presence of fMLP. Inhibitors of phosphatidylinositol 3-kinase (PI3-K), protein kinase C (PKC), and protein tyrosine kinase (PTK) had no effect on random migration induced by GM-CSF, whereas fMLP-induced movements were partially inhibited by PTK inhibitors but not by inhibitors of PI3-K inhibitors nor PKC inhibitors. Myosin light chain kinase inhibitors inhibited movements of PMNs induced by both GM-CSF and fMLP. These findings also imply that some aspects of the signal transduction pathway of GM-CSF leading to random migration is different from that of fMLP. Our findings suggest that cell movements are controlled through diverse signal transduction systems.

[Intravascular lymphomatosis diagnosed by bone marrow biopsy].

Intravascular lymphomatosis (IVL) is a rare malignancy characterized by neoplastic proliferation of lymphoid cells within the lumina of small vessels. We report a case of IVL in a 69-year-old woman, who presented with pancytopenia and elevation of the serum LDH level. There was no skin eruption or neurological abnormalities. Clusters of abnormal lymphoid cells were barely evident in a peripheral blood smear. Laboratory examinations revealed high levels of LDH (2,602 IU/l) and sIL-2R (5,640 U/ml). Bone marrow aspiration revealed a normal cellular marrow with mild hemophagocytosis, but no tumor cells were detected. After admission, respiratory failure due to multiple pulmonary embolisms progressed, and continuous infusion of heparin had no apparent effect. Bone marrow vessels filled with lymphoma cells were observed in a biopsy specimen, thus establishing a diagnosis of IVL. Chemotherapy with the CHOP regimen was immediately instituted. The respiratory failure was dramatically improved, resulting in disappearance of the abnormal lymphoid cells from the bone marrow. After eight courses of CHOP, low-dose etoposide therapy was administered, and no symptoms of relapse were noticed. The diagnosis of IVL is difficult because it does not form masses of tumor cells. Bone marrow biopsy may be helpful for early diagnosis of IVL if the disease is suspected and searched for.

[Polycythemia vera with der(15) and der(20) associated with remarkable neutrophilia].

An autopsy case of polycythemia vera with der(15) and der(20) associated with remarkable neutrophilia was reported. A 87-year-old man was diagnosed as polycythemia vera in August 1987. The red blood cell count was 621 x 10(4)/microliters, Ht 58.5% and the white blood cell count 45,400/microliters with 92% neutrophils. The splenomegaly, increased red blood cell volume and the low erythropoietin level were present. The arterial SaO2 value was above 92%. The chromosome analysis of bone marrow cells revealed 46, XY, -15, -20, +der(15)t(15;?)(q13-15;?), +der(20)t(20;?)(q11;?). The breakpoint in No. 20 was in q11. The remarkable leukocytosis with relative and absolute neutrophilia were observed. Particularly late in the clinical course the white blood cell count was 92,900/microliters with 99% neutrophils. The Ph1 chromosome was negative and the bcr rearrangement was not detected. He died of bronchopneumonia in January 1989. At the autopsy findings neither the marrow fibrosis nor the extramedullary leukemic cell infiltration was noticed.

[Complete remission in acute myeloblastic leukemia (M0) after treatment with rhG-CSF].

A 57-year-old man was admitted because of fever and night sweat. The bone marrow was hypercellular with 86.4% blast cells. The diagnosis of AML (M0) was made, because the blast cells were negative for peroxidase stain and had CD13 and no lymphoid antigens in marker analysis. The patient was treated with BH-AC.TMP, BH-AC.MVP and low dose Ara-C without any hematological improvement, and even additional treatment with medium dose Ara-C resulted in 66.4% blast cells in the bone marrow. Subsequent administration of rhG-CSF (150 micrograms/day) by continuous intravenous infusion resulted in the decrease of the blast cells in the bone marrow to a level that was evaluated as complete remission. He remains in complete hematological remission at present. As shown in this case, rhG-CSF might be an effective agent for the treatment of AML, even if the mechanism of its effectiveness is unclear at present. Further clinical studies should will supply useful information to analyze the pathophysiology of AML.

[Successful treatment with donor leukocyte transfusion followed by interferon-alpha in a patient with relapsed chronic myelogenous leukemia after allogeneic bone marrow transplantation].

A 44-year-old man with CML in chronic phase was admitted for BMT from an HLA-identical sibling. Ph positive cells were undetectable at 3 and 7 months after BMT but became detectable by cytogenetic analysis of bone marrow aspirates at 12 months after BMT. He was treated with IFN-alpha (6 million units/day, 3 times a week) without apparent effect. Donor leukocyte transfusion (DLT) was performed four times between 20 months and 23 months after BMT, transfusing 3.4 x 10(8) mononuclear cells/kg. However, leukocytosis appeared and the NAP score declined at 25 months after BMT. FISH analysis revealed an increase in bcr-abl positive cells. IFN-alpha was restarted using the same schedule at 26 months after BMT. Three months after restarting IFN-alpha, the leukocyte count fell to the normal range, NAP score increased to a normal level, and bcr-abl positive cells decreased markedly. He has remained in hematological and cytogenetic remission for 20 months, and bcr-abl chimeric mRNA remained undetectable by PCR. These results suggest that CML which does not respond to DLT may be cured by subsequent IFN-alpha therapy, possibly by inducing anti-leukemia immune responses.

Down-regulation of CXCR2 expression on human polymorphonuclear leukocytes by TNF-alpha.

TNF-alpha is implicated in the initiation of cytokine cascades in various inflammatory settings. To assess the interactions of multiple cytokines at the level of inflammatory effector cells, we examined the effects of TNF-alpha on the expression of two IL-8Rs (CXCR1 and CXCR2) on polymorphonuclear leukocytes (PMNs). TNF-alpha decreased the surface expression of CXCR2 in a dose- and time-dependent manner. In contrast, CXCR1 expression was not affected by TNF-alpha. The release of CXCR2 into the supernatant of TNF-alpha-treated PMNs was detected by immunoblotting and immuno-slot-blot analyses, suggesting that the down-regulation of CXCR2 was caused mainly by shedding from the cell surface. The CXCR2 down-regulation was inhibited by PMSF and aprotinin, supporting the hypothesis that the shedding was mediated by serine protease(s). The intracellular Ca2+ mobilization and chemotaxis in response to IL-8 were suppressed by the pretreatment of PMNs with TNF-alpha, indicating that the decrease in CXCR2 was reflected in the decreased functional responses to IL-8. In contrast, the O2- release, which is mediated by CXCR1, was not suppressed by TNF-alpha. The treatment of whole blood with TNF-alpha also caused a significant reduction in CXCR2 and markedly suppressed intracellular Ca2+ mobilization and chemotaxis in response to IL-8, while enhancing the O2- release. These findings suggest that TNF-alpha down-regulates CXCR2 expression on PMNs and modulates IL-8-induced biologic responses, leading to the intravascular retention of PMNs with an enhanced production of reactive oxygen metabolites.

The expression of co-stimulatory molecules and their relationship to the prognosis of human acute myeloid leukaemia: poor prognosis of B7-2-positive leukaemia.

We examined the expression of co-stimulatory molecules on leukaemic cells of 52 adult patients with acute myeloid leukaemia (AML) (34 men and 18 women) and analysed the relationship between these expressions and the patient's prognosis. B7-1 was not expressed in any of the 23 patients investigated, whereas B7-2 was expressed in 26/52 patients (50.0%). B7-2 was expressed in all AML patients with monocytic morphology (M4 or M5) and in 16/42 cases without monocytic morphology. CD54 was expressed in 28/ 37 patients examined (75.7%), and CD58 was expressed in all of the AML patients except one (M 7). The overall survival of the 26 B7-2-positive leukaemia patients (1-24 months, median survival 11.5 months) was significantly shorter than that of the 26 B7-2-negative leukaemia patients (1-71+ months, median 35.1 months) (P=0.0080). In addition, the B7-2-positive patients exhibited significantly shorter disease-free survival periods compared to the B7-2-negative patients (P=0.021). There was no significant difference in age, sex, haematological data and complete remission rate between the B7-2-positive and B7-2-negative patients. Our results indicated that B7-2 is one of the most crucial factors in the prognosis of adult acute leukaemia and can be expected to have an important role in tumour immunity.