Eosinophilia associated with adult T-cell leukemia: role of interleukin 5 and granulocyte-macrophage colony-stimulating factor

Lymphoproliferative disorders associated with hypereosinophilia

Hypereosinophilia, defined as peripheral blood eosinophil counts > 1,500/μL, may complicate the course of various lymphoproliferative disorders. Among these, Hodgkin lymphoma (HL) and certain peripheral T-cell lymphomas (PTCLs) derived from CD4 cells, including Sezary syndrome (SS), adult T-cell leukemia/lymphoma (ATLL), and angioimmunoblastic T-cell lymphoma (AITL), are most commonly associated with increased reactive eosinophilopoiesis. Rarely, marked hypereosinophilia (HE) may occur in the setting of acute B-cell lymphoblastic leukemia, with a substantial impact on disease course. The mechanisms leading to blood and tissue eosinophilia in the setting of lymphoproliferative disorders, as well as the clinical complications and prognostic implications of hypereosinophilia, are discussed in this review.

Immune activation induces immortalization of HTLV-1 LTR-Tax transgenic CD4+ T cells

Infection with the human T-cell leukemia virus-1 (HTLV-1) results in a variety of diseases including adult T-cell leukemia/lymphoma (ATL). Although the pathogenesis of these disorders is poorly understood, it involves complex interactions with the host immune system. Activation of infected T cells may play an important role in disease pathogenesis through induction of the oncogenic HTLV-1 Tax transactivator protein. To test this hypothesis, we employed transgenic mice in which Tax is regulated by the HTLV-1 LTR. T-cell receptor stimulation of LTR-Tax CD4(+) T cells induced Tax expression, hyper-proliferation, and immortalization in culture. The transition to cellular immortalization was accompanied by markedly increased expression of the antiapoptotic gene, mcl-1, previously implicated as important in T-cell survival. Immortalized cells exhibited a CD4(+)CD25(+)CD3(-) phenotype commonly observed in ATL. Engraftment of activated LTR-Tax CD4(+) T cells into NOD/Shi-scid/IL-2Rγ null mice resulted in a leukemia-like phenotype with expansion and tissue infiltration of Tax(+), CD4(+) lymphocytes. We suggest that immune activation of infected CD4(+) T cells plays an important role in the induction of Tax expression, T-cell proliferation, and pathogenesis of ATL in HTLV-1-infected individuals.

Follicular lymphoma with marked infiltration of eosinophils

Eosinophilia and tissue infiltration by eosinophils are frequent findings in Hodgkin lymphoma, but they are extremely rare in B-cell lymphoma. Reported herein is a case of follicular lymphoma with extensive lymph node infiltration by eosinophils. The patient was a 71-year-old woman who had a mass in the vicinity of the pancreas found on routine ultrasonography. Subsequent CT indicated several enlarged abdominal lymph nodes, although superficial lymph nodes were not palpable. Two swollen mesenteric lymph nodes were excised to determine the cause of the lymphadenopathy. Histology indicated extensive infiltration of numerous eosinophils to the interfollicular area, especially in the dilated sinuses. The lymphoid follicles were relatively small, had inconspicuous germinal centers, and were scattered between dilated sinuses. Based on the histology, immunohistochemistry, and chromosomal abnormality, a diagnosis of follicular lymphoma was made. Expression of interleukin-3 (IL-3), IL-5, eotaxin, eotaxin-2, and eotaxin-3 was investigated on reverse transcription-polymerase chain reaction of the lymph node tissue, but none of the mRNA expression levels were elevated. This was a unique case of follicular lymphoma with extensive eosinophil infiltration, and to the best of the authors' knowledge this is the first such case ever reported.

Impact of visceral involvements and blood cell count abnormalities on survival in adult T-cell leukemia/lymphoma (ATLL)

Multiple visceral involvements and various blood cell count abnormalities are frequently manifested in adult T-cell leukemia/lymphoma (ATLL) at diagnosis. We evaluated the effects of four visceral involvement (bone marrow (BM), skin, liver, spleen) and six blood cell count abnormalities (anemia, neutrophilia, thrombocytopenia, monocytosis, eosinophilia, basophilia) on the overall survival of 168 ATLL patients. In the aggressive type, BM involvement, skin involvement and monocytosis were significantly poor prognostic factors. Furthermore, concomitant involvement of BM and additional visceral organs worsened the prognosis. These data support that multiple organ involvements represent a poor prognostic factor for ATLL and provide clinical significance for BM examinations.

Clinical significance of a blood eosinophilia in adult T-cell leukemia/lymphoma: a blood eosinophilia is a significant unfavorable prognostic factor

We investigated the clinical significance of a blood eosinophilia in a cohort of 158 consecutive patients with adult T-cell leukemia/lymphoma (ATLL), and multivariate analysis revealed that a blood eosinophilia was an independent and a significant unfavorable prognostic factor. Interestingly, a blood eosinophilia was independent of serum LDH level, which might reflect the tumor burden. The present study shows that measurement of the blood eosinophil count is useful for predicting the prognosis and for determining a suitable treatment strategy for ATLL patients.

Clinical significance of serum Th1-, Th2- and regulatory T cells-associated cytokines in adult T-cell leukemia/lymphoma: high interleukin-5 and -10 levels are significant unfavorable prognostic factors

Patients with adult T-cell leukemia/lymphoma (ATLL) are in a severely immunocompromised state. Therefore, it is assumed that ATLL cells either express particular cytokines or induce their expression in host immune cells, disrupting the balanced production of cytokines and causing the host's immune system to break down. We examined the levels of serum cytokines including T helper type 1- (Th1-) associated cytokines [IFN-gamma, TNF-alpha, and interleukin (IL)-2], Th2-associated cytokines (IL-4, -5 and -6) and regulatory T cell-associated cytokines (IL-10 and TGF-beta1) in 94 ATLL patients, 39 asymptomatic human T-cell lymphotropic virus type-1 (HTLV-1) carriers and 50 healthy adult volunteers, to clarify whether elevated levels of particular cytokines are associated with the prognosis of ATLL patients. On multivariate analysis, high IL-5 and IL-10 levels were independent and significant unfavorable prognostic factors among the ATLL patients. The IL-10 level significantly increased with disease progression at each step from asymptomatic HTLV-1 carrier to ATLL of the indolent variant (chronic and smoldering subtypes) to ATLL of the aggressive variant (acute and lymphoma subtypes). Furthermore, high IL-10 was significantly associated with high lactate dehydrogenase (LDH), indicating that the IL-10 level reflects the tumor burden. The IL-5 level was not associated with disease progression nor LDH. Among ATLL patients with the aggressive variant, high IL-5, but not high IL-10, was an independent and significant unfavorable prognostic factor on multivariate analysis. Measurement of serum IL-5 and IL-10 levels is useful for predicting the prognosis and for determining a suitable treatment strategy for ATLL patients.

IL-2- and STAT5-regulated cytokine gene expression in cells expressing the Tax protein of HTLV-1

Interleukin-2 (IL-2) mediates cell cycle progression and antiapoptosis in human T cells via several signal transduction pathways. The Tax protein of the human T-cell leukemia virus type I (HTLV-1) deregulates cell growth and alters the role of IL-2 in infected cells. However, Tax-immortalized cells stay dependent on IL-2, suggesting that events besides HTLV-1 gene expression are required for leukemia to develop. Here, IL-2-dependent and -independent events were analysed in a human T cell line immortalized by Tax. These studies show that, of the signaling pathways evaluated, only STAT5 remains dependent. Microarray analyses revealed several genes, including il-5, il-9 and il-13, are uniquely upregulated by IL-2 in the presence of Tax. Bioinformatics and supporting molecular biology show that some of these genes are STAT5 targets, explaining their IL-2 upregulation. These results suggest that IL-2 and viral proteins work together to induce gene expression, promoting the hypothesis that deregulation via the constitutive activation of STAT5 may lead to the IL-2-independent phenotype of HTLV-1-transformed cells.

Interferon treatment for hypereosinophilic syndromes and systemic mastocytosis

Hypereosinophilic syndromes (HES) and systemic mastocytosis (SMCD) are heterogeneous disorders with clinical symptoms from local and remote effects of excessive proliferation of eosinophils and mast cells, respectively. Interferon alpha (IFN-alpha), alone or in combination with other medications, can be a useful, and at times life-saving, treatment for patients with HES. Receptors for IFN-alpha are present on eosinophils, and clinical benefits are due to its effect on eosinophil proliferation, migration, activation, and survival. These effects are likely mediated through multiple pathways including, but not limited to, inhibition of eosinophil colony-forming cells, upregulation of IFN-gamma synthesis, and inhibition of production of eosinophil-active cytokines by T cells, mast cells, and mononuclear cells. IFN-alpha has been life-saving for patients with intractable HES that were resistant to prednisone, hydroxyurea, and other agents. Resistance to the eosinopenic effect of IFN-alpha does not develop and the dose of IFN-alpha necessary to maintain control of eosinophilia often decreases with time. The combination of IFN-alpha and hydroxyurea is very useful and allows dosage reduction of IFN-alpha and better control of hypereosinophilia than with either agent alone. The efficacy of IFN-alpha for treatment of SMCD has been more difficult to establish, with both favorable and unfavorable results reported. The disparate results may have resulted from the small number of patients with SMCD treated with IFN-alpha, the use of various criteria for a "successful" treatment outcome, short duration of treatment and follow-up, and the use of modest dosages. In reported series, side effects from IFN-alpha have frequently been dose-limiting. IFN-alpha improves many of the clinical symptoms of SMCD including dermatological, hematological, gastrointestinal, and systemic symptoms associated with histamine release. IFN-alpha has a beneficial effect on skeletal symptoms because of its ability to increase bone density and reduce painful episodes from vertebral fractures. No consistent improvement in bone marrow infiltration by mast cells has been demonstrated except in a recent study employing high dosages of IFN-alpha. A beneficial effect from the combination of IFN-alpha and prednisone has been reported for several patients, suggesting that combined use of these two medications may provide synergism in treatment outcomes.

In situ eosinophil activation in 26 primary cutaneous T-cell lymphomas with blood eosinophilia

Blood and tissue eosinophils can be associated with Hodgkin and non-Hodgkin lymphomas in that they have prognostic value. Tissue eosinophils in T-cell lymphoma patients with blood eosinophilia have not been systematically assessed. The objective of this research was to study the presence, density, and activation of tissue eosinophils in patients with primary cutaneous T-cell lymphomas (CTCLs) with blood eosinophilia and a possible relationship between features of the disease and prognosis. With skin biopsy specimens from 26 CTCL patients with blood eosinophilia, tissue eosinophils were studied with electron microscopy, extracellular eosinophil peroxidase deposits, and interleukin-5 expression. Tissue eosinophils, found in 22 of 26 cases, were constantly activated. Both density and activation of tissue eosinophils were significantly related to disease progression. The state of activation of tissue eosinophils in CTCL might reflect inflammatory flare-ups associated with aggressive lymphomas. Further studies are needed to confirm the value of eosinophil density as a simple and reliable marker of CTCL progression.

Update in the pathologic features of mature B-cell and T/NK-cell leukemias

Modern diagnosis of mature B- and T-cell leukemias requires integration of morphologic, immunophenotypic, and molecular genetic features. This integrative approach has allowed more precise definitions of specific disease entities. This in turn provides better information for clinicians to select proper therapy and determine prognosis. The characteristic pathologic features of these disorders are reviewed.

Bone marrow biopsy: interpretive guidelines for the surgical pathologist

Ideally, the bone marrow core biopsy should be reviewed with knowledge of the clinical history, complete blood count, and findings in the peripheral blood and bone marrow aspirate smears. However, for a variety of reasons, the pathologist may receive the core biopsy and aspirate clot section without all of this information. Although this approach is not optimal, a great deal of valuable information can be generated from these specimens. Over the past 20 years, there has been considerable progress in the fields of flow cytometric analysis, immunohistochemistry, and molecular diagnostic studies that can be performed on smears or extracted DNA from paraffin embedded tissue. These modalities have augmented and refined diagnostic criteria formerly ascertained by light microscopy, cytochemistry, and cytogenetics. This is particularly true of some myeloid and lymphoreticular neoplasms where a collaborative and multidisciplinary approach to the diagnosis has become necessary. Despite this growing complexity and dependence on newer methodologies, the traditional role of histopathology in evaluating the bone marrow biopsy remains as important as it has been in the past. In this review, we focus on contemporary practices and expectations for interpreting bone marrow biopsies and clot sections.

Chronic eosinophilic leukaemia presenting with erythroderma, mild eosinophilia and hyper-IgE: clinical, immunological and cytogenetic features and therapeutic approach. A case report

A 23-year-old, white male metallurgist presented with pruritic erythematous maculo-papules over the trunk and upper limbs and 6 months later developed erythroderma, eosinophilia and multi-organ dysfunction. A diagnosis of chronic eosinophilic leukaemia was made on the basis of myeloproliferative involvement of both peripheral blood and bone marrow, associated with eosinophilic differentiation and a t(5;12)(q33;p13) translocation. The initial therapeutic approach was interferon alfa-2b plus cytosine arabinoside, for 13 months, followed by hydroxyurea plus vincristine. There was improvement of skin lesions, disappearance of eosinophilia and decrease of serum immunoglobulin E, towards normal values.

Influence of pathological tumour variables on long-term survival in resectable gastric cancer

Although tumour stage and nodal status are established prognostic factors for resectable gastric cancer, the relative importance of other pathological characteristics remains unclear. This study reports univariate and multivariate analyses of the prognostic value of various pathological and staging factors based on 324 patients entered into the MRC randomised surgical trial for gastric cancer. In the univariate analysis tumour stage, nodal status, UICC clinical stage, number of involved nodes, WHO predominant type, mixed Lauren type, Ming type, tumour differentiation, lymphocytic and tumour stromal eosinophilic infiltration were all found to have a significant impact on survival (logrank test, 5% level). In the multivariate analysis, UICC clinical stage and eosinophilic infiltration were found to have a significant influence. Risk of death increased for UICC stage II and III patients (Hazard Ratio for stage II compared to stage I=2.0, 95% Confidence Interval (CI) 1.4-2.9; Hazard Ratio for stage III compared to stage I=3.5, 95% CI 2.5-4.8). Patients with numerous eosinophils had a lower risk of death than those with none (Hazard Ratio=0.5, 95% CI 0.3-0.8). This association between survival and eosinophilic infiltration merits further study.

Mechanism of hypercalcemia in adult T-cell leukemia: overexpression of receptor activator of nuclear factor kappaB ligand on adult T-cell leukemia cells

Hypercalcemia is one of the most frequent and serious complications in patients with adult T-cell leukemia (ATL) and is due to marked bone resorption by accumulation of osteoclasts (OCLs). Although several cytokines such as interleukin 1 and parathyroid hormone-related protein are thought to be involved in the development of high serum Ca(++) levels, its precise underlying mechanism remains unknown. This study analyzed the expression of various genes that are thought to regulate serum Ca(++) levels in ATL and showed that the overexpression of the receptor activator of nuclear factor kappaB (RANK) ligand gene correlated with hypercalcemia. ATL cells from patients with hypercalcemia, which highly expressed the transcripts of the RANK ligand (RANKL) gene, induced the differentiation of human hematopoietic precursor cells (HPCs) into OCLs in vitro in the presence of macrophage colony-stimulating factor (M-CSF). In contrast, ATL cells from patients without hypercalcemia did not induce such differentiation, suggesting that the induction of the differentiation correlated with the expression of the RANKL gene in ATL cells. Cell differentiation was suppressed by osteoprotegerin/Fc, an inhibitor of RANKL, indicating that such differentiation occurred through the RANK-RANKL pathway. In addition, direct contact between ATL cells and HPCs was essential for the differentiation, suggesting that not the soluble form but membrane-bound RANKL played a role in this process. These results strongly suggested that ATL cells induce the differentiation of HPCs to OCLs through RANKL expressed on their surface, in cooperation with M-CSF, and ultimately cause hypercalcemia.

Roles of CCAAT/enhancer-binding protein in transcriptional regulation of the human IL-5 gene

Interleukin-5 (IL-5) plays a critical role in the pathogenesis of eosinophil-associated allergic disorders, such as asthma. IL-5 may also play a major role in the development of eosinophilia-associated lymphoproliferative disorders caused by human T lymphotropic virus type I (HTLV-I). In this study, we have investigated the control mechanisms for IL-5 production and found that ectopic expression of NF-IL6 (C/EBPbeta) increases endogenous IL-5 mRNA expression. The IL-5 promoter contains four C/EBP consensus sequences. We show here that one of the C/EBP site at - 235 promoter region binds to NF-IL6 protein with high affinity and interacts with NF-IL6 and NF-IL6beta (C/EBPdelta) in Jurkat T cells. Mutations within the C/EBP sequence reduced the promoter activity in response to T cell activation by more than 50 %. In addition, we show that in vivo inducible expression of Tax protein in Jurkat T cells stably transfected with Tax further increased ionomycin plus phorbol ester stimulated IL-5 promoter activity. The effect of Tax on IL-5 promoter activity was abolished when the C/EBP site was mutated. Thus, the C/EBP site may be also involved in HTLV-I Tax-mediated up-regulation of IL-5 gene expression. Our data suggest that C/EBP proteins may regulate IL-5 gene expression in response to different stimulation signals.

Hypereosinophilia

Recent advances in our understanding of hypereosinophilia have related particularly to the definition of criteria for distinguishing between eosinophilic leukemia and the 'idiopathic' hypereosinophilic syndromes. In this article, leukemogenic mechanisms have been identified in a number of subtypes of eosinophilic leukemia, and the role of clones of T lymphocytes in the causation of otherwise unexplained eosinophilia has been further elucidated. The roles of various therapeutic modalities-including cytotoxic chemotherapy, interferon and bone marrow transplantation-in eosinophilic leukemia and in the idiopathic hypereosinophilic syndrome also have been further defined.