We describe a 65-year-old woman with follicular lymphoma (FL), grade 1, stage IV, which occurred concurrently with B lymphoblastic leukemia/lymphoma. Through the evaluation of FL, the cells that were morphologically suspected of having undergone transformation were found in the bone marrow, and flow cytometric and cytogenetic analyses detected the transformed population that suggested concomitant t(8;22) with typical t(14;18) FL cells. Repeated analyses of the lymph nodes demonstrated the typical morphological, phenotypic, and cytogenetic features of FL. The patient received several multiagent chemotherapy regimens, but the disease gradually became resistant, and the patient died of leukemic progression. In B-cell malignancies, cases involving both BCL2 and MYC translocations simultaneously, so-called "double-hit leukemia/ lymphoma (DHL)", have occasionally been reported. Patients with this type of translocation have a very poor clinical outcome, and no standard therapy has been established. In our case, FL was supposed to have transformed into B lymphoblastic leukemia via Burkitt's lymphoma-like phase. Our case is unique in that the transformed DHL cells, derived from clonally related FL cells, showed ongoing transformation from Burkitt-like feature to B lymphoblastic leukemia exclusively in the bone marrow, which suggests that the bone marrow may provide a preferable milieu for malignant transformation. Similar cases should be accumulated and analyzed carefully. 〔J Clin Exp Hematopathol 52(2) : 113-119, 2012〕

SummaryStudies in mice have shown that CD70 on dendritic cells (DCs) is sufficient to convert T-cell tolerance into immunity and hence induce antitumour immune responses. Therefore, it is important to investigate (i) optimal stimuli to induce CD70 on human monocyte-derived DCs (MoDCs), which are widely used for tumour immunotherapy, and (ii) the role of CD70 in functional differentiation of naive CD4 + and CD8 + T cells stimulated with MoDCs. We show that interferon-a (IFN-a) is a key cytokine to differentiate monocytes into DCs with the capacity to express CD70 upon maturation. CD70 expression on IFN-a-induced MoDCs was elicited by different categories of maturation-inducing factors (Toll-like receptor ligands, CD40 ligand and pro-inflammatory mediators), among which prostaglandin E 2 was most effective. Naive T cells stimulated with MoDCs also expressed CD70. Stimulation with MoDCs promoted naive CD4 + T cells to acquire the ability to produce T helper type 1 and 2 cytokines in a CD70-dependent manner. In contrast, the CD70-CD27 interaction diminished the production of an immunoregulatory cytokine IL-10. The CD27 signal did not play a dominant role in the induction of effector molecules in naive CD8 + T cells during the stimulation with MoDCs. This study adds a novel function to the versatile cytokines, type I IFNs, that is, the induction of CD70 on MoDCs. CD70 promotes naive CD4 + T cells to acquire immunostimulatory activity through the DC-T-cell and T-cell-T-cell interactions during the stimulation with MoDCs. Hence, the CD70-CD27 interaction may play an important role in inducing effective immune responses in DC-based immunotherapy.

Abstract

Progressive multifocal leukoencephalopathy (PML) is a rare and fatal demyelinating disease of the central nervous system caused by JC polyomavirus (JCV) reactivation in an immunocompromized host. We describe a case of PML in a 76-year-old woman with myelodysplastic syndrome, who had been treated with azathioprine for a pure red cell aplasia-like condition. PML was diagnosed based on the neurologic symptoms, the magnetic resonance imaging patterns and the detection of JCV DNA in the cerebrospinal fluid. She died ten months after the diagnosis. An autopsy confirmed the diagnosis, and JCV DNA was detected in the cerebrum. Azathioprine might have triggered PML.

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