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The diagnosis of human T-cell leukemia virus type-1 (HTLV-1) infection has been widely examined by serologics. In the first screening tests, serological false negative and positive samples have been reduced thanks to advances in assay techniques that apply new emission agents and sensors. On the other hand, western blot (WB) remains problematic. For example, WB analysis yields many samples equivalent to antibody positive ones. To reduce the need for WB, an alternative testing strategy is required to detect HTLV-1 infection. Polymerase chain reaction (PCR) for the HTLV-1 provirus has recently been recommended for a final diagnosis of infection. However, although PCR is thought to be one element, the validation of detection performance for HTLV-1 infection between serological and molecular testing is not always clear. Thus, this study aimed to evaluate the accuracy and test the validity of an improved methodology for serological detection of HTLV-infection, as well as that of PCR. In conclusion, the high values of kappa-statistics are expected to deliver high quality in chemiluminescent enzyme immunoassay (or chemiluminescent immunoassay), while the problems with WB assays remain to be elucidated. As an alternative to WB, a combination of real-time qPCR and nested PCR is proposed as a suitable confirmatory test.

Aberrant overexpression of membrane-associated mucin (MUC1) is implicated in the pathogenesis of cancer, particularly of adenocarcinomas. Adult T-cell leukemia/lymphoma (ATL), an aggressive neoplasm etiologically associated with human T-lymphotropic virus type-1 (HTLV-1), exhibits invasive tropism into various organs, resulting in disease progression and resistance to treatment. In the present study, we showed that MUC1 is overexpressed exclusively in cells of ATL among hematological malignancies. Furthermore, increased expression of MUC1 correlated with a poor prognosis, suggesting MUC1 to be a prognostic marker in ATL. Various functional analyses with knockdown experiments using a specific siRNA for MUC1 revealed that MUC1 is involved in cell growth, cell aggregation, and resistance to apoptosis. Although it has been shown that the anti-adhesive properties of MUC1 facilitate migration and metastasis of tumor cells, our findings indicated that MUC1 contributes to cell-cell adhesion. Mucins thus seem to play a role in the pathogenesis and/or progression of ATL.

Adult T-cell leukemia/lymphoma (ATLL) is a malignancy of mature T-cell origin with multi-organ involvement. Because the chemokine receptors play crucial roles in tissue-specific homing of mature lymphocytes, particular chemokine receptors expressed on ATLL cells may be involved in their tissue infiltration. We thus performed a comprehensive survey on the chemokine receptor expression in ATLL. ATLL cells expressed transcripts of CCR1, CCR4, CCR7, CCR8, CCR10 and CXCR4 but hardly expressed those of CCR2, CCR3, CCR5, CCR6, CCR9, CXCR1, CXCR2, CXCR3 and CXCR5. These results were confirmed at the protein level by flow cytometric analysis. Notably, patients who have skin lesions showed significantly higher levels of CCR10 mRNA expression than patients without skin lesions. ATLL cells migrated efficiently to the CCR4 ligand, CCL22, and moderately to the CCR10 ligands, CCL27 and CCL28. Moreover, ATLL skin lesions consistently contained transcripts of CCR10 and its ligands CCL27 and CCL28 besides those of CCR4 and its ligands CCL17 and CCL22 that have been reported previously. Collectively, the frequent co-expression of CCR4 and CCR10, the known pair of skin-homing chemokine receptors, may play an important role in ATLL invasion into the skin.

B-cell chronic lymphocytic leukemia (B-CLL) is the most common leukemia in Westerners. By contrast, B-CLL is rare in Asians, including Japanese. We applied comparative genomic hybridization (CGH) to screen 26 newly diagnosed Japanese B-CLL patients for genomic aberrations. Chromosomal imbalances were detected in 12 of the 26 cases (46%). The most frequent changes observed were gains of chromosomes 3q in five cases (19%) and 17q in three cases (12%). Other recurrent imbalances included gains of chromosomes 8q, 18q and losses of chromosomes 13q and 17p. Samples obtained at different sites disclosed identical CGH findings in all of the three cases examined. Genomic imbalances as detected by CGH were associated with disease progression and shorter survival. Two patients, with chromosomal imbalances, including gains of both 3q and 18q, developed large cell transformation of the disease within 4 years. In conclusion, CGH abnormality was associated with poor prognosis in Japanese B-CLL, and features of Japanese B-CLL, compared to chromosomal abnormalities of Western B-CLL in the literature, include a lower incidence of any abnormality in particular regarding gain of 12q, with the exception of a higher incidence of gains at 3q.

Almost three decades have passed since adult T-cell leukemia-lymphoma (ATLL) was proposed as a new disease entity. During this period, its causative agent, human T-cell leukemia virus type-1 (HTLV-1), was found and a crucial role of the viral product Tax in the development of ATLL was disclosed. However, the long latent period after infection with HTLV-1 indicates the need for additional factors for full-blown ATLL, most of which are supposed to be provided by somatic mutations of cellular genes. Recent progress in cell-cycle research has revealed that the uncontrolled and superior proliferative activity of malignant cells is mainly caused by the breakdown of cell-cycle regulation and that most malignancies carry aberrations in p16-pRB and/or p53 pathways. ATLL is not an exception, despite the consistent association of HTLV-1 in primary leukemia cells, and accumulating evidence indicates that the breakdown of these pathways is indeed involved in the leukemogenesis of ATLL, especially in its later steps, which serve as the key events for promotion of indolent ATLL to aggressive ATLL.

Survivin is a 16.5-kDa protein that belongs to the inhibitor of apoptosis (IAP) family. It is expressed at high levels in the G2/M phase and is rapidly down-regulated after cell-cycle arrest. It was suggested that survivin plays a pivotal role in linking cell death and cell proliferation. Although present during fetal development, survivin disappears in terminally differentiated adult tissues. Its expression is aberrantly enhanced in transformed cell lines, and in all the most common human cancers. Adult T-cell leukemia (ATL), which is abundant with Fas (Apo-1/CD95), has the characteristic feature of high tumor burden, suggesting that ATL cells probably prolong their lives as a result of escape from apoptosis. Survivin is prominently and consistently expressed in all cases of ATL and ATL cell lines. Its mRNA expression levels among the subtypes of ATL and ATL cell lines are characteristic and informative, low in chronic type, low to high in acute type and extremely high in ATL cell lines. In addition, when the survivin mRNA expression is higher, the survival of the patient is shorter. Its overexpression may account for a growth advantage in vivo and subsequently the malignant behavior of ATL. So quantification of survivin mRNA is important for clinical laboratory examinations. Among all of the current clinical tests for survivin mRNA quantification, the real time PCR is desirable. Despite some technological problems of standardization, quantification of survivin mRNA was shown to be a biological marker for clinical stages or minimal residual disease (MRD).

Fas (APO-1/CD95) consists mainly of 2 isoforms, membrane-anchored (mFas) and soluble (sFas), both of which can mediate apoptosis through the Fas-signalling process, not only in normal but also in leukemia T-cells. This suggests that aberrant expression of either mFas or sFas may affect the natural history of T-cell neoplasms, such as adult T-cell leukemia (ATL). For studying the tumor biology related to Fas-mediated apoptosis, ATL cells with up-regulated Fas proteins and its mRNAs are convenient and useful for understanding apoptotic oncology as it occurs in nature. Most attention, so far, has been focused on mFas, and little is known about neoplasms from the viewpoint of sFas. Accordingly, we herein review and discuss the biological and clinical implications of sFas in ATL.

Interleukin-15 (IL-15) is a 14-kDa glycoprotein belonging to the same four helix bundle-cytokine family as IL-2. Although the biological activity of IL-15 in vitro has been studied extensively, its physiological role is still obscure. The receptors for IL-15 and IL-2 consist of three subunits, an unique alpha chain and shared beta and gamma chains. Since beta and gamma chains transduce the signals from the receptors, both cytokines share similar biologic functions, although IL-15 and IL-2 do not have sequence homology. The alpha chains function to increase binding affinity for each cytokines. Adult T-cell leukemia (ATL) cells constitutively express the IL-2 receptor (IL-2R) alpha and expression is believed to be essential in the early stages of disease development. We have recently shown that ATL cells also express the complete form of IL-15R including the alpha chain, and that ATL cells proliferate in response to exogenous IL-15. Since the mRNA of IL-15 is ubiquitous and is detected in many tissues and cells, it is possible that IL-15R stimulation is involved in the development and progression of ATL. Here, we review recent studies on IL-15 and IL-15R and their association with ATL and other lymphoproliferative disorders.

Using semi-nested polymerase chain reaction (PCR), we examined 75 Japanese cases of hematologic malignancies with B-cell antigens including 25 common acute lymphoblastic leukemia (ALL), 13 chronic lymphocytic leukemia (CLL), 28 B-cell malignant lymphoma (B-ML), 2 hairy cell leukemia (HCL), 7 acute myelogenous leukemia with B-cell antigens (AML-B), and 23 controls. When amplified products were analysed by a standard polyacrylamide gel electrophoresis, the sensitivity for detection of clonal IgH rearrangements in each group of ALL, CLL, B-ML, HCL, and AML-B was 88%, 92.3%, 71.4%, 100%, and 57.1%, respectively, with an overall sensitivity of 80.0%. There were no false positive results in any of the control samples. Single strand conformation polymorphism (SSCP) analysis of the amplified products gave rise to a much greater sensitivity, up to 84% overall. The false negative samples were mainly encountered in B-ML with SmIgG and non-Ig, suggesting miss-annealing between the primers used and the template DNA because of somatic hypermutation of IgH genes in such clones. This indicates that PCR analysis is very useful in detecting the clonal IgH rearrangements in B-cell malignancies, especially in ALL and CLL, but not in B-ML corresponding to neoplasms originating from pre-germinal center naive B-cells.

We examined 111 patients with acute type- or lymphoma type-adult T-cell leukemia (ATL) and compared them with 106 patients with non-Hodgkin's lymphoma (NHL). In addition to skin involvement and hypercalcemia which are already known to be frequent in ATL, ATL patients showed an higher incidence of hepatic involvement. There was more frequent palpable hepatomegaly, higher total bilirubin, GOT, GPT, lactate dehydrogenase (LDH), and alkaline phosphatase values in ATL than in NHL patients (p < 0.0001). Among 36 autopsied liver samples, invasion of ATL cells was confirmed in 22 cases. ATL patients with impaired hepatic function showed shorter survival times than patients without hepatic dysfunction. Moreover, ATL patients showed a worse performance status (PS), a higher incidence of lytic bone lesions, lower total protein (TP) and serum albumin levels than NHL patients. This invasive characters of ATL cells and consequent impaired general condition seemed to be factors affecting the poor prognosis recorded in ATL.

The plasma concentration of macrophage colony-stimulating factor (M-CSF) was measured in 10 patients with acute type adult T cell leukemia (ATL) during the clinical course before and after chemotherapy. M-CSF concentration decreased significantly when the patients achieved complete remission (CR) or partial remission (PR) (t-test: p = 0.0001). Five of the patients showed disease progression after several months of PR, and plasma M-CSF increased at that time (t-test: p = 0.0456). Thus, plasma M-CSF concentration appeared to accurately reflect the disease activity in ATL. In support of these results, all three ATL cell lines established from these patients secreted M-CSF in vitro after stimulation with phorbol myristate acetate (PMA) or concanavalin A (Con A). Plasma M-CSF concentration, however, increased transiently when the patients were febrile (t-test: p = 0.0001), even though their ATL condition was unchanged. Taken together, these results indicate that there are two sources of increased plasma M-CSF concentration in ATL; ATL cells themselves and normal parenchymal cells that cause this increase as the result of elevated body temperature due to inflammation.

To characterize CD5+ B-cell neoplasms in Japan, where chronic lymphocytic leukemia (CLL) is rare and of different subtypes in comparison with Western countries, we collected 58 cases of CD5+ B-cell lymphomas/leukemias and analyzed their clinicopathologic features. According to the French-American-British (FAB) and standard histologic classification, the cases corresponded to small lymphocytic lymphoma (SLL, group I; n = 22, consisting of CLL, n = 10, CLL/PL, n = 3, and CLLmixed, n = 7); intermediate differentiated lymphoma/mantle cell lymphoma (IDL/MCL, group II, n = 18); and others with CD5-positive lymphomas (group III, n = 18). The CD5+ B-cell lymphomas showed morphologic and prognostic variability among the three groups. The clinical and immunophenotypic features were remarkably consistent in leukemic disease being seen in 73% of all cases, splenomegaly in 63%, and intense CD19, CD20, surface membrane immunogobulin M (SmIgM) or SmIgM and SmIgD, light-chain expression, and no CD10 expression. The median survival time of groups I, II, and III was 7.8, 3.3, and 0.8 years, respectively. These findings suggest that CD5 antigens may serve as valid markers for the prognosis and clinical features of B-cell lymphomas and that CD5+ B-cell lymphomas with an overall poor prognosis occurs at a relatively high frequency in Japan. This also suggests that a combination of immunophenotypic and morphologic features is of value for characterizing CD5+ B-cell neoplasms.

Adult T cell leukemia (ATL) cells show a mature helper-inducer T cell phenotype and are thought to secrete many kinds of cytokines in vivo, complicating the clinical features in these patients. In an attempt to specify the cytokines produced by ATL cells, we measured the cytokine concentration in the culture supernatants of three ATL cell lines, all of which were confirmed to be true peripheral blood ATL cell in origin. All these cell lines showed the same cytokine production profile, secreting IL1-alpha, IL1-beta, LD78(MIP-l alpha), TNF-alpha, IFN-gamma, and GM-CSF, but not secreting IL-1 alpha, IL-1 beta, IL-1 receptor antagonist (IL-1 Ra), IL-4, IFN-alpha, and G-CSF irrespective of the stimulatory agents used. Such limited cytokine production may indicate the specific origin of ATL cells within the helper-inducer T cell subtypes. Moreover, these results explain some of the unusual clinical features of ATL patients.

We investigated the phenotypes of blast cells of 53 patients with acute leukemia by a modified streptavidin-biotin alkaline phosphatase (SAB-AP) labeling technique, using a panel of monoclonal antibodies [MoAb; anti-CD11b, CD13, CD14, CD33, CD34, CD41, CD3, CD7, CD10, CD19, anti-HLA-DR, and anti-myeloperoxidase (MPO)]. The selection of an optimal fixative solution for each antigen from five options of various combinations of formalin, acetone, methanol, and/or ethanol, successfully conserved cell morphology and improved specific reaction compared with the conventional methods which used a single fixative for multiple antigens. We compared the SAB-AP results with those obtained by flow cytometry (FCM) for surface markers in each case. High concordance rates for both positive and negative results were observed for each marker. However, positive reaction for some markers (anti-CD13, CD14, CD33, and CD34) were often noted only in the cytoplasm by the SAB-AP method, indicating that combination of these two methods is essential for the precise immunophenotyping of poorly differentiated leukemia cells.

We have analyzed the clinical and laboratory features of 42 patients with B-cell leukemia. Based on the FAB criteria, the cases were classified in 3 groups: I) typical CLL 15, II) atypical CLL 9 which included 6 cases with large cells, and III) B-cell lymphoma in leukemic phase 18. Cases diagnosed as typical CLL (group I) had similar features to those seen in CLL patients from Western countries. The morphology and markers in cases from group III corresponded to B-cell lymphoma in leukemic phase. On the other hand, group II included 3 cases classified as atypical CLL according to FAB criteria. 1 CLL/PL and 2 mixed CLL and 6 cases with rather distinct features, namely: 1) lymphocytosis (42 +/- 41 x 10(9)/l in average) with large mature-looking lymphocytes with abundant cytoplasm: 2) an immunological profile consistent with CLL but, in addition with the consistent expression of CD38; 3) absence of a monoclonal band in the serum and 4) a clinical course and prognosis similar to CLL. Our findings suggest the existence of a B-cell disorder in Japan very close to CLL but distinct from typical and atypical CLL as seen in Western countries. Further studies would clarify whether such an entity is exclusively confined to Japan having a distinct natural history.

Plasma concentration of M-CSF was measured in 35 patients with adult T cell leukemia (ATL), using a radioimmunoassay (RIA). ATL patients showed elevated levels of plasma M-CSF concentration when compared with healthy adult volunteers. Higher M-CSF levels were observed in acute ATL patients than in patients with chronic or smouldering ATL (P < 0.0001). There was a significant positive correlation of M-CSF concentration with serum lactic dehydrogenase (LDL) level, a reliable marker for assessing the grade of malignancy in ATL (P = 0.0003). There was, however, no correlation of M-CSF concentration with total counts of peripheral blood ATL cells, neutrophils or monocytes, or with serum calcium levels. Although there was a significant positive correlation of M-CSF concentration with body temperature (P = 0.003), there was not a significant correlation of M-CSF concentration with C-reactive protein (CRP), a protein indicative of the severity of inflammation (P = 0.063). These results indicate that plasma M-CSF concentration reflects the disease activity of ATL, and can thus serve as a marker in the clinical subclassification of ATL patients.

We describe 4 cases of adult T-cell leukemia (ATL) with unusual morphology and aberrant immunophenotype. All patients were Japanese and born in the Nagasaki district, an area endemic for HTLV-I. Peripheral blood and/or bone marrow films revealed bizarre giant cells with and without large nucleoli; the cells were 5 to 6 times the diameter of erythrocytes, resembling Hodgkin's cells. Some peripheral blood cells were morphologically similar to prototypic ATL cells, while many other cells in the bone marrow showed unusual morphology. Furthermore, leukemic cells had aberrant immunophenotypes such as the CD8-positive type in patients 1 and 2, the CD4-.CD8- double-negative type in patient 3, and the CD5 antigen defect in patient 4. All patients had marked elevations of the serum calcium and LDH and organomegaly, while all had a short survival. Anti-HTLV-I antibodies and provirus DNA monoclonality were demonstrated in all patients. The results suggested that the unusual morphology and aberrant ATL cell immunophenotype may be indicative of a high grade malignant behaviour of ATL.