Failure to detect human T-lymphotropic virus type-I proviral DNA in cell lines and tissues from patients with cutaneous T-cell lymphoma

Role of infectious agents in cutaneous T-cell lymphoma: facts and controversies

The etiology of cutaneous T-cell lymphoma (CTCL) remains unknown, with potential infectious causes having been explored. This contribution evaluates the evidence suggesting an infectious etiology and pathogenesis of the disease, characterizes the relationships between various specific pathogens and CTCL, and discusses some of the difficulties in establishing a causal link between infectious agents and CTCL carcinogenesis. Researchers have evaluated CTCL specimens for evidence of infection with a variety of agents, including human T-lymphotropic virus, Epstein-Barr virus, human herpesvirus-8, and Staphylococcus aureus, although other pathogens also have been detected in CTCL. Although there is significant evidence implicating one or more infectious agents in CTCL, studies to date have not linked definitively any pathogen to disease development, and various studies have yielded conflicting results.

The non-Hodgkin lymphomas: a review of the epidemiologic literature

The non-Hodgkin lymphomas (NHL) are a heterogeneous group of B-cell and T-cell neoplasms that arise primarily in the lymph nodes. NHL incidence rates in the US doubled between about 1970 and 1990, and stabilized during the 1990s. NHL accounts for approximately 3.4% of cancer deaths in the US. Although some of the observed patterns in NHL have been related to HIV/AIDS, these conditions cannot fully explain the magnitude of the changes; neither do changes in classification systems nor improved diagnostic capabilities. Studies of occupational and environmental exposures (e.g., pesticides, solvents) have produced no consistent pattern of significant positive associations. Inverse associations with ultraviolet radiation exposure and alcohol and fish intake, and positive associations with meat and saturated fat intake have been reported in several studies; additional studies are needed to confirm or refute these associations. Family history of NHL or other hematolympho-proliferative cancers and personal history of several autoimmune disorders are associated with increased risk of NHL, but are not likely to account for a large proportion of cases. HIV and other infectious agents, such as human herpesvirus 8 and Epstein-Barr, appear to be associated with differing types of NHL, such as some B-cell lymphomas. Future epidemiologic studies should evaluate associations by NHL type, enhance exposure information collected, and elucidate factors that may identify susceptible (or resistant) subpopulations because of genetic, immunologic or other characteristics. The extent to which the etiology of NHL types may differ is important to resolve in ongoing and future studies.

Cutaneous malignant lymphomas: Update 2006

Cutaneous lymphomas represent a unique group of lymphomas and are the second most frequent extranodal lymphomas. As with other neoplasias, the pathogenesis is based mainly on a stepwise accumulation of mutations of suppressor genes and oncogenes caused by genetic, environmental or infectious factors. The diagnostic work-up includes clinical, histological, imaging and hematological investigations and in many cases immunohistochemical and molecular biological analyses. The current WHO/EORTC classification of cutaneous lymphomas differentiates "mature T-cell and NK-cell lymphomas", "mature B-cell lymphomas" and "immature hematopoietic malignancies", their variants and subgroups. It is compatible with the WHO classification for neoplasias of the hematopoietic and lymphoid tissue and respects the organ-specific peculiarities of primary cutaneous lymphomas. The assignment of the various types of cutaneous lymphomas into prognostic categories (pre-lymphomatous "abortive" disorders; definite malignant lymphomas of low-grade malignancy; definite malignant lymphomas of high-grade malignancy) provides essential information on the biological behavior and allows an appropriate planning of the therapeutic strategy, which may be topical or systemic and aggressive or non-aggressive. Besides the classical options for therapy, there are new and "experimental" strategies, the efficacy of which has to be studied in clinical trials.

Localization of human T-cell lymphotropic virus-1 gag proviral sequences in dermato-immunological disorders with eosinophilia

The mechanisms leading to the development of eosinophilia were investigated in 65 patients with immunodermatological disorders, including the role of eosinophilotactic cytokines and the possible involvement of human T-cell leukemia virus, HTLV. HTLV-1 gag proviral sequences were revealed in two cases of lymphoproliferative disorders such as angiolymphoid hyperplasia with eosinophilia (ALHE) and CD4+ cutaneous lymphoma, respectively. Increased level of GM-CSF was detected in 33% of disorders studied. Elevated level of IL-5 and eotaxin was detected in 27% and 30%, respectively, of patients with bullous diseases. Elevated level of GM-CSF and eotaxin was found in 33% and 46%, respectively, of patients with inflammatory diseases. Neither of the four cytokines, however proved to be responsible alone or together for the induction of eosinophilia. The possible indirect role of human retroviruses through induction of eosinophilic chemotactic cytokines is hypothesized.

Classification and prediction of survival in patients with the leukemic phase of cutaneous T cell lymphoma

We have used cDNA arrays to investigate gene expression patterns in peripheral blood mononuclear cells from patients with leukemic forms of cutaneous T cell lymphoma, primarily Sezary syndrome (SS). When expression data for patients with high blood tumor burden (Sezary cells >60% of the lymphocytes) and healthy controls are compared by Student's t test, at P < 0.01, we find 385 genes to be differentially expressed. Highly overexpressed genes include Th2 cells-specific transcription factors Gata-3 and Jun B, as well as integrin beta1, proteoglycan 2, the RhoB oncogene, and dual specificity phosphatase 1. Highly underexpressed genes include CD26, Stat-4, and the IL-1 receptors. Message for plastin-T, not normally expressed in lymphoid tissue, is detected only in patient samples and may provide a new marker for diagnosis. Using penalized discriminant analysis, we have identified a panel of eight genes that can distinguish SS in patients with as few as 5% circulating tumor cells. This suggests that, even in early disease, Sezary cells produce chemokines and cytokines that induce an expression profile in the peripheral blood distinctive to SS. Finally, we show that using 10 genes, we can identify a class of patients who will succumb within six months of sampling regardless of their tumor burden.

Cytomegalovirus seropositivity is significantly associated with mycosis fungoides and Sézary syndrome

Although mycosis fungoides (MF) may arise through persistent antigen stimulation, cytomegalovirus (CMV) is not a known risk factor. To study the incidence of seropositivity to viral infections, we compared MF and Sézary Syndrome (SS) patients to healthy bone marrow donors and other historical control groups. Baseline screening serologies at baseline were performed on 116 biopsy-proven MF/SS patients at MD Anderson Cancer Center from 1992 to 2001 and on healthy bone marrow donors evaluated by the transplant service from 1988 to 2001. Antibodies to HTLV-I/II, HIV-1, EBV, and CMV were measured using standard enzyme-linked immunosorbent (ELISA) and membrane enzyme immunoassay (MEIA) assays. One hundred thirteen (97.4%) of all MF/SS patients had positive CMV IgG serologies at initial presentation. Early- and late-stage patients' seropositivity rates were significantly higher than healthy bone marrow donor controls (chi(2).05(df=1) = 71.79). By stage, 98.1% of early-stage MF patients (IA, IB, IIA; 52/53) and 96.8% of late-stage MF and SS patients (IIB-IVB; 61/63) were seropositive compared with healthy bone marrow donors whose seropositivity rate was 57.3% (757/1322). Because the rate of CMV seropositivity increases with age, a subset of cutaneous T-cell lymphoma (CTCL) patients 55 years or younger were compared to age-matched healthy donor controls; their seropositivity rate for CMV was also significantly higher (chi(2).05 05(df=1) = 20.4). EBV titers were positive by serology in 13 patients who were examined prospectively. CMV seropositivity is highly associated with MF and SS, even in the earliest stages of the disease, and is significantly higher than that of healthy and immunocompromised controls.

Spontaneous interleukin-5 production in cutaneous T-cell lymphoma lines is mediated by constitutively activated Stat3

Mycosis fungoides is a low-grade cutaneous T-cell lymphoma (CTCL) of unknown etiology. In advanced stages of CTCL, a shift in cytokine profile from T(H)1 to T(H)2 is observed, which coincides with eosinophilia, high levels of immunoglobulin E, and increased susceptibility to bacterial infections. It is, however, unknown why T(H)2 cytokines predominate in advanced CTCL, and the cellular source of these cytokines also remains to be identified. In several leukemias and lymphomas, constitutively activated signal transducer and activator of transcription (Stat) signaling pathways have been detected. In a previous study, constitutive activation of Stat3 was found in tumor cells isolated from affected skin and blood from CTCL patients. Here, it is shown that CTCL tumor cell lines, but not nonmalignant cell lines, spontaneously produce interleukin-5 (IL-5), IL-6, and IL-13. Transfection of tumor cells with dominant-negative Stat3 almost completely blocks IL-5 production and strongly inhibits IL-13 production, whereas IL-6 production is unaffected. Thus, the data show that malignant CTCL cells themselves might contribute to the change in cytokine pattern accompanying progression of CTCL. In conclusion, constitutively activated Stat3 is found to mediate a spontaneous IL-5 production and regulate IL-13 production in CTCL cell lines, pointing toward a new role of Stat3 in malignant transformation.

Emerging new therapies for cutaneous T-cell lymphoma

Improved therapy for CTCL will depend on a better understanding of the pathogenesis of this disease at a molecular level. It is clear that the T cells in MF and CTCL do not undergo normal programmed cell death and have prolonged lifespans. Skin flora or other antigens may stimulate the initial proliferation, offering another approach to change the course of the disease. There has been tremendous interest in biological response modifiers, and the first targeted fusion toxin to activated T cells has been approved for CTCL. New retinoids with increased selectivity and decreased side effects are being tested for this disease. In summary, the treatment of CTCL should continue to improve and should be focused on strategies that preserve the immune function in these patients.

Twenty-year trends in the reported incidence of mycosis fungoides and associated mortality

OBJECTIVES

Patterns of mycosis fungoides incidence and associated mortality in the United States were evaluated.

METHODS

Data were taken from the Surveillance, Epidemiology, and End Results cancer registry program and the National Center for Health Statistics.

RESULTS

The incidence rate from 1973 through 1992 was 0.36/10(5) person-years. The age-adjusted incidence rate ratio of Blacks to Whites was 1.7; that of Asians to Whites was 0.6. There was no evidence of increasing incidence rates during the period 1983 through 1992. Mortality rates declined steadily from 1979 to 1991 and were less heterogeneous geographically than incidence rates. Mortality rate patterns with age, sex, and race were similar to the corresponding incidence patterns.

CONCLUSIONS

The incidence rate of mycosis fungoides has stabilized and the mortality rate has declined. For unknown reasons, the disorder varies greatly among demographic and geographic subgroups.

Atypical cutaneous lymphoproliferative disorder in patients with HIV infection

BACKGROUND

An inflammatory pruritic eruption which is characterized histologically by CD8+, atypical lymphocytes has been described in human immunodeficiency virus (HIV)-infected patients. This disorder has been described as "pseudo-Sezary" or a "cutaneous T cell lymphoma (CTCL)-simulant", however, as these patients do not resemble CTCL clinically, and the relationship between this entity and CTCL is unclear, a more descriptive term is "atypical cutaneous lymphoproliferative disorder" (ACLD). The purpose of this study is to categorize the clinical, histologic, and immunophenotypic features of 16 HIV-infected patients with this skin disorder seen at the New York Department of Veterans Affairs Medical Center.

METHODS

A retrospective chart review was conducted on 16 HIV-infected patients with a histologic diagnosis of an atypical cutaneous lymphoproliferative infiltrate on skin biopsy. Skin biopsies were reviewed, and histologic features noted. Immunophenotyping was performed on 14 out of 16 samples; electron microscopy was performed on samples from five patients. Clinical manifestations, disease course, medication history, and response to treatment were noted.

RESULTS

The patients presented with a pruritic, persistent, generalized, papular eruption. Pigment changes, including hyperpigmentation and hypopigmentation were common. Histologically, lesional biopsies were characterized by a superficial and deep polymorphous infiltrate with atypical lymphocytes which were CD8+ predominant, Ki-1 negative, and occasionally CD7 antigen depleted. Sezary-like cells were present in the infiltrate in four out of five patients by electron microscopy. None of the patients has systemic manifestations of lymphoma; however, one of the 16 patients eventually developed frank CTCL.

CONCLUSIONS

HIV-infected patients can present with a pruritic, widespread disorder, often with pigment changes characterized by an atypical cutaneous lymphocytic infiltrate. This clinicopathologic disorder is a rare, reactive inflammatory condition which generally occurs in late stage HIV infection and rarely progresses to frank lymphoma.

Detection of Epstein-Barr virus and HTLV-I in T-cell lymphomas of skin in Taiwan

Viral etiology has been associated with the pathogenesis of T-cell lymphomas of skin (TCLS). Therefore, we studied the presence of Epstein-Barr virus (EBV) and type I human T-cell lymphotropic virus (HTLV-I) in tumor cells of TCLS to determine the significance of these viruses with the disease. A retrospective study was conducted on the skin tissues from 28 Chinese patients with TCLS. We used in situ hybridization, immunohistochemistry, and polymerase chain reaction to determine the presence of viruses. Among the 28 cases, HTLV-I was only detected in two cases with adult T-cell leukemia/lymphoma, not in other cases of TCLS. This suggests that HTLV-I may not play a significant role in the oncogenesis of TCLS in Chinese patients. Conversely, EBV was detected in 12 cases (42.9%), including the secondary TCLS, large cell lymphoma, mycosis fungoides, adult T-cell leukemia/lymphoma, and angiocentric lymphoma. Nevertheless, latent membrane protein 1 was not detected in any of the EBV-positive cases. Neither was any correlation found between the presence of EBV in TCLS and the prognosis or the severity of the skin lesion. Although there is a close association of EBV with a portion of TCLS, its pathogenic role needs further investigation.

Tumor necrosis factor-alpha and interferon-gamma, but not HTLV-I tax, are likely factors in the epidermotropism of cutaneous T-cell lymphoma via induction of interferon-inducible protein-10

We have previously shown that Interferon-Inducible Protein-10 (IP-10), a cytokine chemotactic for CD4-positive lymphocytes, is overexpressed by lesional epidermal keratinocytes and probably accounts for the epidermotropism of cutaneous T-cell lymphoma (CTCL). The tax gene of human T-lymphotropic virus-I (HTLV-I) immortalizes CD4-positive lymphocytes, induces IFN-gamma, and has been detected in patients with classical CTCL who are seronegative for HTLV-I. TNF-alpha is synergistic with IFN-gamma for the induction of IP-10. We therefore decided to define the presence of tax, IFN-gamma, TNF-alpha, and IP-10 in lesions of 19 adults with classical CTCL who were seronegative for HTLV-I. Lesional mRNAs for actin, TNF-alpha, IFN-gamma, and tax were detected by reverse-transcriptase polymerase chain reaction (RT-PCR) amplification. In addition IP-10, TNF-alpha, and IFN-gamma were detected and localized with immunocytochemistry of frozen sections. In agreement with previous observations IP-10 was overexpressed in lesional keratinocytes of all 19 patients. By RT-PCR, mRNA for IFN-gamma was detected in lesions of 8, and for TNF-alpha in lesions of 13 patients. By immunocytochemistry, TNF-alpha was expressed by lesional keratinocytes in 10 of 13 tested patients, whereas IFN-gamma was focally expressed by lesional lymphocytes and faintly by lesional keratinocytes in 9 of 13 tested patients. tax mRNA was not detected in lesions of any patient, but was easily detectable in cutaneous lesions or peripheral blood of control patients who were seropositive for HTLV-I. We conclude that TNF-alpha and IFN-gamma may cause epidermotropism by inducing IP-10. However, the tax gene of HTLV-I does not appear to be involved in the pathogenesis of classical CTCL.

Constitutive activation of a slowly migrating isoform of Stat3 in mycosis fungoides: tyrphostin AG490 inhibits Stat3 activation and growth of mycosis fungoides tumor cell lines

Mycosis fungoides (MF) is a low-grade cutaneous T cell lymphoma of unknown etiology. In this report, the Jak/Stat (Janus kinase/signal transducer and activator of transcription) signaling pathway was investigated in tumor cell lines established from skin biopsy specimens from a patient with MF. Jaks link cytokine receptors to Stats, and abnormal Jak/Stat signaling has been observed in some hemopoietic cancers. In MF tumor cells, a slowly migrating isoform of Stat3, Stat3(sm), was found to be constitutively activated, i.e., (i) Stat3(sm) was constitutively phosphorylated on tyrosine residues, and tyrosine phosphorylation was not enhanced by growth factor stimulation; (ii) band shift assays and immunoprecipitations of DNA/Stat complexes showed constitutive DNA-binding properties of Stat3(sm); and (iii) Stat3(sm) was constitutively associated with Jak3. The abnormal activation of Stat3(sm) was highly specific. Thus, neither the fast migrating isoform of Stat3 (Stat3(fm)) nor other Stats (Stat1, Stat2, and Stat4 through Stat6) were constitutively activated. The Jak kinase inhibitor, tyrphostin AG490, blocked the constitutive activation of Stat3(sm) and inhibited spontaneous as well as interleukin 2-induced growth of MF tumor cells. In conclusion, we have provided evidence for an abnormal Jak/Stat signaling and growth regulation in tumor cells obtained from affected skin of an MF patient.

No evidence of KSHV/HHV-8 in mycosis fungoides or associated disorders

The recently discovered human virus known as Kaposi's sarcoma-associated herpesvirus (KSHV) or human herpesvirus-8 (HHV-8) has been associated with body-cavity-based lymphomas in AIDS patients. It is most closely related to two other herpesviruses, the Epstein-Barr virus and herpesvirus saimiri, which are known to be associated with lymphomas in humans and nonhuman primates, respectively. To determine whether KSHV/HHV-8 is involved in the pathogenesis of mycosis fungoides (MF) and related disorders, we used a genomic PCR assay followed by confirmatory Southern blot analysis with a nested oligonucleotide probe to analyze cases for the presence of this virus. The specimens studied included fresh-frozen lesional tissues obtained from 16 patients with MF, seven with lymphomatoid papulosis, seven with primary cutaneous CD30+ large cell lymphoma of T-cell lineage, and five with Hodgkin's disease. Two T-cell tumor lines were also studied: MT4 (derived from a patient with adult T-cell leukemia/lymphoma) and Jurkat (derived from a patient with T-cell acute lymphoblastic leukemia). All cases were uniformly negative for KSHV/HHV-8, whereas Kaposi's sarcoma-positive controls and human beta-globin DNA integrity controls were appropriately positive. These findings provide strong evidence against a role for KSHV/HHV-8 in the pathogenesis of MF or associated lymphoproliferative disorders.

Evidence against a role for human T-cell lymphotrophic virus type I (HTLV-I) in the pathogenesis of American cutaneous T-cell lymphoma

We used a standard polymerase chain reaction (PCR)/Southern blot assay (sensitivity > 10(-5)) to detect human T-cell lymphotrophic virus type I (HTLV-I) proviral pX, pol, and env genes in the lesional skin of 42 American patients with cutaneous T-cell lymphoma (CTCL). As in some prior reports using similar methods, a variable proportion of PCR tests were positive (seven of 42 for pX, three of 42 for pol, and two of 37 for env), resulting in an overall positive test rate of 12 of 121 (10%). To determine the significance of these positive test results, we performed several additional studies. D1S80 polymorphism analysis of CTCL cases and HTLV-I PCR analysis of non-CTCL dermatosis controls showed no evidence that positive PCR tests resulted from sample mislabeling, gross HTLV-I contamination, or human endogenous retroviruses. We then modified the standard PCR assay to incorporate ultraviolet (UV) light to destroy low-level PCR contamination. With this modified assay (sensitivity > 10(-5)), only three of 12 previously positive cases were still positive, suggesting that the earlier positives were due to trace contamination of PCR reagents or trace contamination of sample DNA. This interpretation was also supported by: (i) a match between pX and pol sequences cloned from one PCR-positive specimen and the MT4-positive control, (ii) our inability to confirm HTLV-I in any PCR-positive case using genomic dot blotting (sensitivity > 10(-2)), and (iii) negative PCR results when new samples from two of the remaining positive cases were analyzed. Finally, we used our modified UV/ PCR/Southern blot assay to test an additional 28 cases of American CTCL for pX. All of them were negative. Although these studies of 70 cases of American CTCL do not exclude the possibility that another virus is involved in the pathogenesis of this disease, they provide strong evidence against a role for HTLV-I. Furthermore, they emphasize the need for special strategies to control for false-positive PCR tests that can result from even trace levels of contamination with viral DNA. As a consequence, associations between diseases and viruses should be viewed skeptically if they are based primarily on conventional PCR data.