Detection of human T-lymphotropic virus-like particles in cultures of peripheral blood lymphocytes from patients with mycosis fungoides

Single-Cell Heterogeneity of Cutaneous T-Cell Lymphomas Revealed Using RNA-Seq Technologies

Cutaneous T-cell lymphomas (CTCLs) represent a large, heterogeneous group of non-Hodgkin lymphomas that primarily affect the skin. Among multiple CTCL variants, the most prevalent types are mycosis fungoides (MF) and Sézary syndrome (SS). In the past decade, the molecular genetics of CTCL have been the target of intense study, increasing the knowledge of CTCL genomic alterations, discovering novel biomarkers, and potential targets for patient-specific therapy. However, the detailed pathogenesis of CTCL development still needs to be discovered. This review aims to summarize the novel insights into molecular heterogeneity of malignant cells using high-throughput technologies, such as RNA sequencing and single-cell RNA sequencing, which might be useful to identify tumour-specific molecular signatures and, therefore, offer guidance for therapy, diagnosis, and prognosis of CTCL.

Epidemiology and Etiopathology of Human T-Lymphotropic Viruses: Diagnostic and Clinical Implications for Non-Endemic Areas

Human T-lymphotropic viruses (HTLV) type I and II were first described more than a decade ago. HTLV-I epidemiology and etiopathology are more defined than those of HTLV-II, but conflicting results have been obtained in seroepidemiologic surveys, mainly for difficulties in the discrimination between the two infections. The introduction of advanced serologic and molecular assays has recently provided sensitive and specific tools for diagnosis, and the epidemiologic and etiopathologic patterns linked to these retroviruses are being more precisely defined. Moreover, extensive nucleotide sequence analyses performed so far have mainly focused on HTLV-I isolates. The recent discovery of new HTLV-II endemic areas and the isolation of HTLV-II strains from intravenous drug users have finally provided the material for the molecular characterization of HTLV-II isolates, which is now a rapidly envolving field. We review the diagnostic strategies available and the etiologic associations reported so far for both viruses and also discuss the occurrence and significance of indeterminate serologic reactivities observed in both endemic and non-endemic areas.

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.

Infectious agents in cutaneous T-cell lymphoma

Infectious agents have long been suspected as potential causative agents in cutaneous T-cell lymphoma (CTCL). Tissues of patients with CTCL have been evaluated for evidence of infection with a number of agents, including Staphylococcus aureus, retroviruses, and herpesviruses. These studies have failed to reveal a consistent association of CTCL with investigated agents. However, there is substantial evidence suggesting a potential role of a yet unidentified virus in CTCL. This article will review the findings of studies exploring potential roles of infectious agents in CTCL. In addition, we investigated CTCL tissues for evidence of infection with Merkel cell polyomavirus, a novel polyomavirus that was recently discovered as a probable carcinogenic agent in Merkel cell carcinoma. Cutaneous lesions demonstrating mycosis fungoides were stained with a monoclonal antibody against the Merkel cell polyomavirus T antigen, along with appropriate positive and negative controls. Immunohistochemical stains produced negative results in all examined mycosis fungoides specimens. These findings, which suggest a lack of association of CTCL with Merkel cell polyomavirus, add to the current body of knowledge regarding infectious agents and CTCL.

Current views in HTLV-I-associated adult T-cell leukemia/lymphoma

Epidemiological studies have demonstrated that the relative percentage of malignant lymphoid proliferations varies widely according to geographical location and ethnic populations. HTLV-I is the etiological agent of adult T-cell leukemia/lymphoma (ATLL) and is also associated with cutaneous T-cell lymphoma (CTCL). However, a definite role of HTLV-I in mycosis fungoides (MF) and/or Sezary syndrome (SS) remains controversial. While most HTLV-I-infected individuals remain asymptomatic carriers, 1-5% will develop ATLL, an invariably fatal expansion of virus-infected CD4+ T cells. This low incidence and the long latency period preceding occurrence of the disease suggest that additional factors are involved in development of ATLL. In this review, diagnosis, clinical features, and molecular pathogenesis of HTLV-I are discussed.

Localization of HTLV-I tax proviral DNA in mononuclear cells

The tax sequence of HTLV-I is demonstrable in the skin and blood mononuclear cells of patients with mycosis fungoides, as well as in the mononuclear leukocytes of some healthy blood donors, but was not demonstrable when PCR/Southern analyses were carried out on preparations of high-molecular-weight genomic DNA. Therefore, it was postulated that tax DNA may not be integrated. To investigate this possibility fluorescence in situ hybridization was carried out on cells arrested in metaphase, using a probe containing the HTLV-I tax proviral DNA full-length open reading frame coding sequence. While metaphases prepared from C91PL cells, a cell line infected with HTLV-I, showed an abundance of chromosome-associated as well as extra-chromosomal signals, metaphases prepared with blood mononuclear cells from healthy tax sequence positive donors did not reveal any tax DNA associated with chromosomes. Such signals were readily detected extra-chromosomally. Although it has been demonstrated that transactivation of genes by gene products encoded by extra-chromosomal DNA may have nosocomial implications, whether transactivation by p40 tax generated from extra-chromosomal tax sequences is responsible for the development of neoplasia remains to be investigated.

Mycosis fungoides: HLA class II associations among Ashkenazi and non-Ashkenazi Jewish patients

BACKGROUND

An immunogenetic mechanism has been suggested to play a role in the pathogenesis of mycosis fungoides (MF). While results of studies on HLA class I associations haveproved inconsistent, two previous studies showed that certain HLA class II alleles were significantly increased among North American caucasian patients with MF: HLA-DRB1*11 and DQB1*03.

OBJECTIVES

To investigate the possible HLA class I and class II associations with MF among Jewish patients.

METHODS

The patient group comprised 68 Jewish patients with MF: 38 Ashkenazi and 30 non-Ashkenazi. The control group comprised 252 healthy Jewish volunteers: 132 Ashkenazi and 120 non-Ashkenazi. Tissue typing for HLA class I (A and B) was performed using the National Institutes of Health microlymphocytotoxicity technique. DNA-based low-medium resolution analysis for DRB1* and DQB1* alleles was performed using polymerase chain reaction (PCR) amplification with sequence-specific primers. For those alleles found to have significantly increased frequency, high-resolution analysis was done by means of PCR sequence-specific oligotyping.

RESULTS

The allele frequency of HLA-DRB1*11 was found to be significantly increased but only among Ashkenazi patients with MF (30% vs. 19% in the controls; P = 0.034). High-resolution analysis for DRB1*11, not previously performed, suggested that its greater frequency is due to the increased number of Ashkenazi MF patients with the DRB1*1104 allele (P corrected = 0.036). Analysed together, DQB1*03 alleles (DQB1*0301-0304) had a significantly greater frequency in MF as a group as compared with controls (47% vs. 33%, P = 0.003). DQB1*0301 was demonstrated to be the specific allele associated with MF in Jewish patients (allele frequency of 36% vs. 23% in controls; P corrected = 0.0068), which was not the case for North American caucasian patients with MF. No greater frequencies of any of the HLA class I A or B antigens were found.

CONCLUSIONS

Our findings further demonstrate the 'universality' of MF HLA class II susceptibility alleles, i.e. HLA-DRB1*11 and HLA-DQB1*03, suggesting that HLA polymorphism is likely to be important in the pathogenesis of MF in Jewish patients, as it is in North American caucasian patients. Not previously reported is our finding that HLA-DRB1*1104 is the specific allele more prevalent among patients with MF. Our study also underscores some differences in HLA profiles between non-Jewish and Jewish patients with MF and between Ashkenazi and non-Ashkenazi Jewish patients, indicating the possibility of diverse HLA disease associations in populations with different genetic backgrounds. Our study provides further evidence for the lack of association between HLA class I and MF.

The role of human T cell lymphotropic virus type I tax in the development of cutaneous T cell lymphoma

Although it has been well established that the human T cell lymphotropic virus type I (HTLV-I) causes adult T cell leukemia/lymphoma (ATLL) in regions of the world where this virus is endemic, its role in the pathogenesis of cutaneous T cell lymphoma (CTCL) in the Western world has been less well established. Most patients with CTCL are negative for antibodies to the structural proteins of HTLV-I, and thus a causative role for this virus is usually dismissed. However, the Tax sequence of HTLV-I has been found in the peripheral blood mononuclear cells of practically all patients with CTCL. Such patients express Tax mRNA and have antibodies to p40Tax, the protein encoded by this sequence. Sequence analysis of a 159-bp region of Tax extracted from CTCL cells proved to be homologous with the same region prepared from a cell line infected with prototypic HTLV-I. By in situ PCR, Tax has been demonstrated in the lymphocytes infiltrating the skin as well as in the keratinocytes of such patients. Apart from the pathophysiologic and clinical interest of these studies, these observations may have therapeutic implications. In vitro, the proliferation of HTLV-I-transformed cells can be inhibited by antisense to HTLV-I Tax. Since Tax has not been identified in the normal human genome, antisense to Tax deserves serious consideration as a treatment modality for patients whose cells have been demonstrated to harborTax.

Epstein-Barr virus-negative Hodgkin's lymphoma after mycosis fungoides: molecular evidence for distinct clonal origin

The association of mycosis fungoides (MF) and Hodgkin's lymphoma is a relatively frequent occurrence, but the potential clonal relationship of the two neoplasms is still controversial. We report a case of a patient with a history of MF in Clinical Stage 1A who developed retroperitoneal lymphadenopathy 9 years after the initial diagnosis of MF. A bone marrow biopsy obtained at this time showed nodular involvement by a mixed cellular infiltrate with large, atypical cells consistent with Hodgkin and Reed-Sternberg (RS) cells. These atypical cells were positive for CD30 and CD15 and did not express B- or T-cell markers. In addition, they lacked evidence of infection by Epstein-Barr virus, both by immunohistochemical staining for latent membrane protein 1 and by in situ hybridization for EBER1/2. The background population consisted mainly of small T cells without morphological or phenotypical signs of malignancy. Review of the skin biopsy obtained 9 years before showed the typical features of MF. Polymerase chain reaction analysis of the T-cell receptor T-gene confirmed the presence of a clonal T-cell rearrangement in the skin specimen. The bone marrow biopsy, however, showed a polyclonal pattern both for the T-cell receptor gamma-gene, as well as for immunoglobulin heavy chain genes. Isolation of RS cells stained for CD30 was performed by laser capture microdissection. Polymerase chain reaction analysis of several groups of RS cells showed a reproducible biallelic rearrangement of IgH genes, which was confirmed by cloning and sequencing of polymerase chain reaction products. To our knowledge, this is the first case in which a distinct clonal origin of MF and Hodgkin's lymphoma arising in the same patient is clearly demonstrated, based on molecular analysis of microdissected RS cells.

Evidence for the cofactor role of human T-cell lymphotropic virus type 1 in mycosis fungoides and Sézary syndrome

The aetiology of mycosis fungoides (MF) and Sézary syndrome (SS) is unknown. A pathogenic role for the human T-cell lymphotropic virus type 1 (HTLV-1) has been suggested but remains controversial. We used an animal model to test the possibility that peripheral blood mononuclear cells (PBMC) obtained from MF patients harbour the HTLV-1 virus which may be infective. The polymerase chain reaction (PCR) was used to detect HTLV-1 proviral DNA sequences in PBMC of 27 MF patients and one SS patient of non-Iranian origin. Positive results were found in six of the patients. Twelve of the 28 patients tested by Western blot showed HTLV-1 antibodies. Twenty-eight immunosuppressed inbred Fisher F344 rats were inoculated intravenously with cultures of PBMC obtained from the 28 patients. Eight of these 28 rats showed antibodies to HTLV-1 while the proviral genome was demonstrated in the blood of only two of the rats. PBMC from two MF patients, in spite of showing negative results for the proviral genome by PCR, still induced HTLV-1 antibody formation in the F344 rat model. None of 10 control rats inoculated with normal donor PBMC showed antibodies to HTLV-1, nor the proviral genome. The present study suggests that HTLV-1 plays a cofactor role in MF/SS patients.

Adult T-cell leukemia/lymphoma in northeastern Brazil: a clinical, histopathologic, and molecular study

The state of Bahia in the northeastern coast of Brazil is a region in which HTLV-I infection is endemic. This study investigated the characteristics of 28 HTLV-I-associated lymphomas/leukemias in this region. HTLV-I-infection diagnosis was based on serologic study, Southern blot analysis, and polymerase chain reaction (PCR) in neoplastic tissue. The main clinical differences between these lymphomas and adult T-cell leukemia (ATL) cases from other endemic areas were as follows. The mean age was 47 years; 20% of the cases occurred in young adults; and a predominance was found among male subjects (2:1), blacks, and of those of mixed race (96%). Histologically, 20 cases were T-cell pleomorphic leukemia/lymphoma, 5 were Mycosis fungoides-like cutaneous lymphoma, and 3 were CD30+ large-cell anaplastic lymphoma. Immunohistochemistry demonstrated 4 cases of CD8+ lymphoma. Proviral genomic sequences were demonstrated by PCR in 9 lymph node biopsy specimens and in 3 skin biopsy specimens. Southern blot was performed and was positive in 8 cases.

Lupus erythematosus-like features in patients with cutaneous T-cell lymphoma

BACKGROUND

The development of lupus erythematosus-like (LE-like) features in patients with cutaneous T-cell lymphoma (CTCL) has not been reported previously in the literature. Both diseases, however, have been etiologically linked to retroviruses.

OBJECTIVE

Our purpose was to report four cases of patients with CTCL who developed LE-like features during the course of their disease, and to evaluate for evidence of antibodies to retroviruses in the sera of these patients.

PATIENTS

Four patients with biopsy-proven CTCL with clinical or histologic features of systemic lupus erythematosus (SLE) were evaluated for clinical and laboratory criteria for SLE. Only one patient demonstrated four American Rheumatism Association (ARA) criteria sufficient for the diagnosis of SLE. The remaining three patients demonstrated one or two criteria for SLE. In addition, the sera of these patients were examined by Western blot analysis for evidence of human immunodeficiency virus type I (HIV-I), human T-cell lymphotrophic virus type I (HTLV-I), or human intracisternal A-type particle type I (HIAP-I) retroviral proteins. Each patient demonstrated antibodies to some of the retroviral proteins examined. The sera of two patients reacted to proteins for HIAP-I, and the sera of two patients reacted to p24 gag proteins of HIV-I. No patient reacted to HTLV-I proteins.

CONCLUSIONS

Our report identifies four patients with CTCL who developed LE-like features during the course of their disease. Although the etiology of CTCL and SLE has not been well established, each has been linked to retroviruses. Evidence of antibodies to retroviral proteins was identified in each of our patients by Western blot analysis. Although the clinical and laboratory findings in these cases do not resolve the etiologic role of retroviruses in CTCL or SLE, they suggest that retroviruses may have a role in the pathogenesis of the clinical phenomenon reported in these four patients.

Reexamination of human T cell lymphotropic virus (HTLV-I/II) prevalence

In the United States, blood donors are being screened for infection with human T cell lymphotropic viruses I and II (HTLV-I/II) by serologic means, which detect antibodies to the structural proteins of these viruses. Because patients with mycosis fungoides (MF) usually do not have such antibodies even though their cells harbor HTLV-I Tax and/or pol proviral sequences, it was questioned whether the prevalence of HTLV infection among healthy blood donors may also be underestimated by current means of testing. To examine this possibility, a study on specimens of relatives of mycosis fungoides patients (MFR) was begun. In addition, to collect data more expeditiously, a cohort of former injection drug users (IDUs) was tested by routine serologic methods, as well as by PCR/Southern blot analysis for Tax, pol, and gag proviral sequences and Western blot analysis for antibodies to the Tax gene product. To date, 6/8 MFRs and 42/81 (51.8%) of HIV-negative IDUs proved to be positive for HTLV, whereas routine serology identified none of the MFR and only 18/81 (22.2%) of the IDUs. Among the latter test subjects, the incidence of HTLV-I also proved to be 10 times higher than expected. Therefore, it is likely that among healthy blood donors infection with HTLV-I/II is more prevalent than is currently assumed. Since Tax is the transforming sequence of HTLV-I/II, testing for Tax sequences and antibodies to its gene product may be desirable in blood transfusion and tissue donor facilities.

Absence of Human T-Lymphotropic Virus Type I in Japanese Patients With Cutaneous T-Cell Lymphoma

Cutaneous T-cell lymphoma (CTCL) is a disease entity characterized by a primary sporadic T-cell proliferation in the skin. Human T-lymphotropic virus type 1 (HTLV-1) is a retrovirus that causes adult T-cell leukemia/lymphoma. Recently, several authors have detected the HTLV-1 genome in genomic DNA from patients with CTCL and proposed a causal relation of HTLV-1 to CTCL. However, it remains controversial because these studies contain some problems in materials used to detect HTLV-1. We investigated both fresh and cultured T lymphocytes (128 specimens) derived from 50 Japanese patients with CTCL, where HTLV-1 is endemic, by using polymerase chain reaction with four sets of primers including gag,pol,env, and pX regions of HTLV-1 to elucidate the relationship between HTLV-1 and CTCL in Japan. However, none of the 128 DNA specimens revealed positive for HTLV-1 in contrast to the previous studies. We conclude that CTCL, which does not include HTLV-1, is present although the pathogenesis of CTCL may be different by areas or races. © 1997 by The American Society of Hematology.

Absence of Human T-Lymphotropic Virus Type I in Japanese Patients With Cutaneous T-Cell Lymphoma

Cutaneous T-cell lymphoma (CTCL) is a disease entity characterized by a primary sporadic T-cell proliferation in the skin. Human T-lymphotropic virus type 1 (HTLV-1) is a retrovirus that causes adult T-cell leukemia/lymphoma. Recently, several authors have detected the HTLV-1 genome in genomic DNA from patients with CTCL and proposed a causal relation of HTLV-1 to CTCL. However, it remains controversial because these studies contain some problems in materials used to detect HTLV-1. We investigated both fresh and cultured T lymphocytes (128 specimens) derived from 50 Japanese patients with CTCL, where HTLV-1 is endemic, by using polymerase chain reaction with four sets of primers including gag,pol,env, and pX regions of HTLV-1 to elucidate the relationship between HTLV-1 and CTCL in Japan. However, none of the 128 DNA specimens revealed positive for HTLV-1 in contrast to the previous studies. We conclude that CTCL, which does not include HTLV-1, is present although the pathogenesis of CTCL may be different by areas or races. © 1997 by The American Society of Hematology.

No evidence of HTLV-I proviral integration in lymphoproliferative disorders associated with cutaneous T-cell lymphoma

Several recent studies have reported detection of HTLV-I genetic sequences in patients with cutaneous T-cell lymphoma (CTCL) including mycosis fungoides and Sezary syndrome. The purpose of this study was to determine whether HTLV-I was detectable in lesional tissues of patients suffering from diseases known to be associated with CTCL. Thirty-five cases were obtained from diverse geographical locations including Ohio, California, Switzerland, and Japan. Six of them had concurrent CTCL. Cases were analyzed using a combination of genomic polymerase chain reaction (PCR)/ Southern blot, dot blot, and Southern blot analyses. All assays were specific for HTLV-I provirus. Sensitivity ranged from approximately 10(-6) for PCR-based studies to 10(-2) for unamplified genomic blotting. Lesional DNA from patients with lymphomatoid papulosis (fourteen cases), Hodgkin's disease (twelve cases), and CD30+ large-cell lymphoma (nine cases) was tested for the HTLV-I proviral pX region using a genomic PCR assay followed by confirmatory Southern blot analysis with a nested oligonucleotide pX probe. All cases were uniformly negative. All of the Hodgkin's disease cases, eight of the large-cell lymphoma cases, and six of the lymphomatoid papulosis cases were then subjected to dot blot analysis of genomic DNA using a full-length HTLV-I proviral DNA probe that spans all regions of the HTLV-I genome. Again, all cases were negative. Finally, eleven of the Hodgkin's disease cases were also subjected to Southern blot analysis of EcoRI-digested genomic DNA using the same full-length HTLV-I probe. Once again, all cases were negative. These findings indicated that, despite utilization of a variety of sensitive and specific molecular biological methods, HTLV-I genetic sequences were not detectable in patients with CTCL-associated lymphoproliferative disorders. These results strongly suggest that the HTLV-I retrovirus is not involved in the pathogenesis of these diseases.

Human T cell leukemia virus type I (HTLV-I) and human diseases

HTLV-I infection is causally associated with a variety of human diseases including leukemia/lymphoma, myelopathy, uveitis, and arthropathy. Tax protein of HTLV-I, which is considered oncogenic, binds to transcription factors or other cytoplasmic cellular molecules involved in the fundamental cell function and thereby induces cellular changes. The interaction between HTLV-I-infected cells with dysregulated function and different kinds of cells in the host, such as lymphocytes and vascular endothelial cells through viral peptides, antigen receptors cell adhesion molecules, and cytokines, appears to be one of the basic mechanisms underlying the development of HTLV-I-associated diseases. This interaction may play a major role in determining tumorigenicity and in forming clinical features of the diseases. The in vivo cell proliferation model of HTLV-I-infected cells using severe combined immunodeficient (SCID) mice can differentiate tumorigenicity from cell immortalization in vitro. The OX40 and its ligand gp34, which are induced by HTLV-I infection and directly mediate the adhesion between HTLV-I-infected T cells and vascular endothelial cells, may be critically involved in the localization and proliferation of HTLV-I-infected cells in vivo.

HTLV-associated diseases: human retroviral infection and cutaneous T-cell lymphomas

An array of neurologic, oncologic, and autoimmune disorders are associated with infection with the human pathogenic retroviruses human T-cell leukemia virus types I and II (HTLV-I, II), as well as the human immunodeficiency viruses (HIV). The cutaneous T-cell lymphomas, mycosis fungoides (MF) and its hematogenous variant Sezary Syndrome (SS), share similar clinical and pathological features to HTLV-I-associated adult T-cell leukemia (ATL) and speculation of a retroviral link to MF and SS, especially in areas non-endemic for ATL, has lead to an intensified search for HTLV- and HIV-like agents in these diseases. To further explore a potential role for human retroviruses in MF and SS, skin biopsy-derived or peripheral blood mononuclear cell-derived DNA from 17 patients (MF, n = 7; erythrodermic MF (EMF), n = 5; SS, n = 5) from the North Eastern United States were screened using gene amplification by PCR and a liquid hybridization detection assay. Previously published primers and probes for HTLV-I (LTR, gag, pol, env, and pX), and our own primers and probes for HTLV-I (gag, pol, and env), HTLV-II (pol and env) and HIV-I (gag and pol) were employed. Serum antibodies to HTLV-I were negative in all but one EMF patient. The single HTLV-I seropositive patient carrying a diagnosis of EMF generated positive amplified signals for all of the eight HTLV-I regions tested. Ultimately, this individual evolved to exhibit clinical manifestations indistinguishable from ATL. The other 16 patients were negative for all 12 HTLV and HIV retroviral regions. Our findings suggest that none of the known prototypic human retroviruses are associated with seronegative MF and SS. The uniformly positive results for HTLV-I in the seropositive patient suggests that this patient initially presented with a smoldering form of ATL and illustrates the difficulty that sometimes may be encountered in the differential diagnosis of MF, SS, and ATL based solely on clinical and histopathological criteria.

The difficulty of detecting HTLV-1 proviral sequences in patients with mycosis fungoides

Although most patients with cutaneous T cell lymphomas, including mycosis fungoides (MF) and its leukemic variant, the Sézary syndrome, are seronegative for antibodies to the human T cell lymphotropic viruses (HTLV-I/II), it has recently been shown that > 95% of such patients harbor proviral DNA sequences related to the region of the HTLV genome that encodes the transregulatory/transforming gene, tax. However, the demonstration of HTLV sequences, even after amplification by polymerase chain reaction (PCR), has not been universally successful, and some investigators continue to question this observation. In an effort to resolve this controversy, we have compared published methodologies that have been less successful with techniques currently used in this laboratory. Major differences were found in (a) the nature of the cells used [freshly isolated versus cultured peripheral blood mononuclear cells (PBMC)] and (b) the methods used to prepare samples for PCR (whole cell lysates versus DNA extracts). PBMC from 10 different MF patients and the healthy daughter of 1 of the patients were subjected to comparative analyses. While all of the PBMC lysates were positive, the DNA extract from only one of these individuals revealed HTLV tax sequences. Studies were also conducted comparing cell lysates and DNA extracts of cultured cells derived from tax sequence-positive PBMC from seven different MF patients. The cells from four of the seven were shown to have retained tax sequences after varying times in culture, when whole-cell lysates were used as targets for PCR amplification and Southern analysis, whereas none of the DNA extracts were positive. It appears that the use of whole-cell lysates instead of DNA extracts and the use of fresh instead of cultured cells greatly enhance the ability to detect HTLV-1 tax sequences in specimens from MF patients.

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

Previous molecular studies investigating the presence of HTLV-I proviral DNA in cell lines and tissue samples of patients with cutaneous T-cell lymphoma (CTCL) have reported a detection rate ranging from 0-92%. Despite the lack of epidemiologic data linking HTLV-I infection with CTCL, the molecular data still invite speculation regarding the precise role of HTLV-I in the pathogenesis of CTCL. To determine the detection rate of HTLV-I proviral DNA among CTCL patients referred to our medical center, we analyzed Epstein-Barr virus-transformed cell lines established from peripheral blood of seven CTCL patients and 43 tissue samples from 22 patients with different stages of disease. Genomic DNA was polymerase chain reaction-amplified with primers within the HTLV-I tax gene region. Amplification products were probed with nested oligonucleotide probes by Southern blot analysis. No HTLV-I proviral sequences were detected in the samples (0/50). Using HTLV-I/II pol primers, no HTLV-I pol gene sequences were detected. In tissues from one patient, HTLV-II pol and tax gene sequences were detected; however, HTLV-II proviral integration was not detected by Southern blot analysis of the genomic DNA. Our data suggest: (i) HTLV-I does not appear to be a primary etiologic agent in CTCL; and (ii) HTLV-II pol and tax gene sequences can be detected in a minority of CTCL patients, but this does not necessarily imply an etiologic role.

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.

HLA-DR5 and DQB1*03 class II alleles are associated with cutaneous T-cell lymphoma

Cutaneous T-cell lymphoma (CTCL) may present with eczematous lesions, mycosis fungoides (MF), or as exfoliative erythroderma with circulating atypical cells, Sezary syndrome (SS). The "malignant" T cells are epidermotropic and clonal, but whether they respond to antigen stimulation is unknown. Because CD4+ lymphocytes recognize antigen presented by histocompatibility locus antigen (HLA) class II molecules, and HLA association have been found in autoimmune skin diseases, we determined by allele-specific oligonucleotide typing whether HLA-DR or DQ alleles were associated with CTCL and its two variants MF (n = 47) and SS (n = 23). Phenotypic frequencies were compared by chi-square and Fisher exact test, and p values were corrected independently for either 12 DR or 15 DQ alleles. HLA-DR5, previously associated with MF, was significantly increased in all 70 CTCL patients (31.5%) versus controls (11%) (uncorrected p value [Pnc] = 0.000038, odds ratio [OR] = 3.9, 1.9 < OR < 8.1), in MF patients (34%) (Pnc = 0.000047, OR = 3.62, 1.9 < OR < 10), and in SS patients (26%) (Pnc = 0.03, OR = 3, 0.9 < OR < 9.3). HLA-DQB1*03 alleles (0301, 0302, and 0303) were increased in 72% of all CTCL patients versus 49% of controls (corrected p value [Pc] = 0.014, OR = 2.7, 1.4 < OR < 5.1), in SS (82%) (Pc = 0.05, OR = 4.7, 1.4 < OR < 5), and in MF (67%) (Pnc = 0.024, OR = 2.15, 1 < OR < 4.5). DQB1*0502 was strongly increased in SS patients (Pc = 0.045, OR = 7.75, 1.25 < OR < 48). Although HLA-DQB1*0603 and HLA-DR6 (1301, 1302, and 1402) were decreased in all groups, the decreases were not statistically significant. These data suggest that certain HLA-DRB and DQB1 alleles, also associated with other T-cell-mediated skin diseases, may participate in the pathogenesis of or susceptibility to CTCL.

Localization of human T-cell lymphotropic virus-1 tax proviral sequences in skin biopsies of patients with mycosis fungoides by in situ polymerase chain reaction

The histopathologic diagnosis of mycosis fungoides (MF), even when clinical manifestations of the disease seem convincing, is often tenuous. The observation that practically all patients with MF harbor human T cell lymphotropic virus type I (HTLV-I) proviral sequences in their circulating lymphocytes raised the possibility that such viral footprints could be detected in their cutaneous infiltrates. Application of in situ polymerase chain reaction (PCR) to skin biopsies of 11 of 12 patients demonstrated this assumption to be correct. In addition, cells suspected to be keratinocytes were also positive. None of 10 skin biopsies from a variety of sources used as controls, nor 3 lymph node biopsies from patients with B-cell lymphomas, showed any HTLV proviral sequences on in situ PCR. On the basis of these observations, it is concluded that in situ PCR carried out on skin biopsies of patients with presumptive MF may help to established the diagnosis.

Transgenic mouse models for HTLV-I infection

Human T-cell leukemia virus type I (HTLV-I) was the first human retrovirus isolated and is responsible for at least one form of human leukemia. The pathogenic mechanism(s) whereby HTLV transforms T lymphocytes in vivo is(are) obscure due to its long-term latency and the lack of practical representative animal models. The tax gene of HTLV-I has been implicated in this transformation process because of its ability to transactivate several cellular genes associated with T-cell replication and activation. Here, transgenic mouse models are discussed that express the Tax protein of HTLV-I and provide insights into its role in the cellular transformation process.

Immunoblastic transformation of a Sezary syndrome in a black Caribbean patient without evidence of HTLV-I

We describe an unusual case of Sezary syndrome which transformed into a large T-cell non Hodgkin's lymphoma (immunoblastic) in a black man of Caribbean descent with negative HTLV-I serology and no evidence of HTLV-I infection by DNA analysis using sensitive techniques. The disease presented as a small-cell Sezary syndrome and transformed in an inguinal lymph node one year from diagnosis. Immunological markers in the small and large cells showed a mature T-cell phenotype CD4+, CD8- with expression of T-cell activation markers and a high proliferative rate. Ultrastructural analysis confirmed small Sezary cells with serpentine nucleus in the peripheral blood and immunoblasts in the lymph node. Cytogenetics demonstrated complex clonal chromosome abnormalities with involvement of 7q35, the locus for the beta chain of the T-cell receptor (TCR). Southern-blot analysis showed the same rearrangement of the TCR beta, gamma, delta chain genes in lymph node and peripheral blood cells. Antibodies to HTLV-I were not detected in the serum by ELISA and particle agglutination (PA) nor HTLV-I specific sequences were demonstrated by nested polymerase chain reaction with primers to the envelope proteins, LTR and tax/rex of HTLV-I in both tissues, blood and lymph node. The disease had an aggressive course and was refractory to therapy; the patient died of progressive disease 28 months from presentation. Two unusual features characterised this patient's illness: immunoblastic transformation of a Sezary syndrome in a patient of Afro-Caribbean origin without evidence of HTLV-I DNA sequences and negative HTLV-I serology and the atypical lymph node histology resembling ATLL.

Expression of V beta gene segments by Sezary cells

The T-cell receptor V beta repertoire expressed by Sezary cells was determined in a series of 16 patients whose samples have been shown to contain a majority of tumor cells. By using anti-V beta monoclonal antibodies, polymerase chain reaction analysis of expressed V beta, and, in selected cases, nucleotide sequencing, we have shown that the expressed V beta segments belong to five V beta families (V beta 5, V beta 6, V beta 8, V beta 13, and V beta 18), which contain a large fraction of the T-cell receptor V beta repertoire and do not share significant similarities in complementary determining region 4. V beta segments from these five families were also found to be strongly expressed by CD4 + CD7- peripheral blood cells obtained by fluorescence-activated cell sorting from two healthy donors. The diversity of the V beta repertoire expressed by Sezary cells appears to be similar to that expressed by circulating non-neoplastic T cells. These data do not support the hypothesis that a common superantigen is involved in the initiation of this form of cutaneous T-cell lymphoma.

Reduced surface expression of transforming growth factor beta receptor type II in mitogen-activated T cells from Sézary patients

Sézary syndrome (SzS), the leukemic form of cutaneous T-cell lymphoma, is characterized by clonal proliferation of CD4+ T cells and immune dysfunctions, raising the possibility of cytokine-related abnormalities. We previously described a decreased response to the growth-inhibitory effects of transforming growth factor type beta (TGF-beta) in SzS T cells accompanied by apparent loss of surface type II TGF-beta receptor (TGF beta RII). To specifically determine if defects exist in TGF beta RII protein expression and/or transport in SzS patients, we developed a sensitive flow cytometric method to detect TGF beta RII on the surface and intracellularly in the CD4+ T cells. Our results indicate that unlike normal CD4+ T cells, CD4+ T cells from 9 of 12 SzS patients expressed little, if any, surface TGF beta RII in response to mitogen stimulation. At the intracellular level, however, pools of TGF beta RII were comparable to those in normal CD4+ T cells. This indicates that defective trafficking of this inhibitory cytokine receptor may contribute significantly to the development of this disease.

T-cell malignancies in Brazil. Clinico-pathological and molecular studies of HTLV-I-positive and -negative cases

T-cell malignancies in Brazil have a high seroprevalence rate of HTLV-I antibodies. We have analyzed the disease features in 188 Brazilian patients with a T-cell disorder. These included 40 with T-lymphoblastic leukaemia or lymphoma (T-ALL/T-LbLy) and 148 with mature T-cell diseases: 5 T-prolymphocytic leukaemia, 53 adult T-cell leukaemia/lymphoma (ATLL), 54 cutaneous T-cell lymphomas, 29 pleomorphic T-cell lymphomas and 7 large granular lymphocyte leukaemia. The diagnosis was based on clinical, morphological and immunological features and HTLV-I serology. ATLL in Brazil has the same diseases features as in other endemic regions, the only apparent differences being: age, Brazilian patients being younger than Japanese, and ethnic grouping, one third of Brazilians being white Caucasians of European descent. We applied a scoring system based on the presence or absence of typical features associated with ATLL; hypercalcaemia, cell morphology, immunophenotype, histopathology and HTLV-I status, to see whether it may help in diagnosing cases of ATLL. All had high scores, whereas all other T-cell diseases scored low. Only 5 ATLL cases were HTLV-I-negative by serology, but they had otherwise typical features of ATLL, and their cells did not have HTLV-I proviral sequences by DNA analysis. Such cases suggest that ATLL may develop in a minority of individuals living in regions where it is endemic, without evidence of HTLV-I infection, and that other factors may contribute to the pathogenesis of the disease.

The cutaneous T cell lymphoma, mycosis fungoides, is a human T cell lymphotropic virus-associated disease. A study of 50 patients

For nearly two decades it has been suspected that the cutaneous T cell lymphoma, mycosis fungoides (MF), and its leukemic variant, the Sézary syndrome, are caused by the human T lymphotropic virus (HTLV-I/II). Arguments against this concept included the finding that only a small number of MF patients have antibodies to HTLV-I/II and that attempts to detect proviral sequences by mere Southern hybridization of extracted DNA usually met with failure. However, we have reported repeatedly that HTLV-like particles emerge in blood mononuclear cell (PBMC) cultures of practically all patients with this disease. In several instances, the particles were identified as HTLV by immunoelectron microscopy as well as biomolecular analysis. With the assumptions that the virus in MF patients may have become detection by Southern hybridization alone, the extracts of freshly isolated PBMC of 50 consecutive patients were subjected to combined PCR/Southern analysis. Here we report the presence of HTLV pol and/or tax proviral sequences in 46 out of 50 (92%) of the patients tested. In addition, five of the patients, who lacked antibodies to HTLV-I/II structural proteins, were found to be seropositive for tax. It thus seems reasonable to conclude that MF/Sézary syndrome is an HTLV-associated disease and that lack of an immune response does not preclude infection with this type of virus.

Genotraumatic T cells and cutaneous T-cell lymphoma. A causal relationship?

Mycosis fungoides, or cutaneous T-cell lymphoma (CTCL), is a T-cell mediated chronic inflammatory skin disease, which can occasionally progress with a variable time course to a fatal lymphoma or to a leukaemic form called Sézary's syndrome. Extensive research into CTCL has not yet elucidated the primary pathophysiological mechanisms. Immunohistological studies are so far less helpful than expected in establishing early diagnosis and prognosis of the disease. The proposition that an exogenous virus is the cause of CTCL has not been substantiated. Karyotypic analysis of lymphocytes from the skin and blood of patients with CTCL have shown the existence of several genetically aberrant T-cell clones in the same patient. These changes are discussed as potential primary events for the development of CTCL. The hypothesis is put forward that the development of genotraumatic T lymphocytes is involved in the progression of the disease.

Persistence of human T cell lymphotropic virus type 1 (HTLV-1) sequences in peripheral blood mononuclear cells from patients with mycosis fungoides

Mycosis fungoides (MF) is a rare form of cutaneous T cell lymphoma suspected of having a viral etiology. As in adult T cell leukemia, the virus involved may be human T lymphotropic virus type 1 (HTLV-1). We cultured the peripheral blood mononuclear cells (PBMC) of 29 patients with MF HTLV-1 seronegative by enzyme-linked immunosorbent assay and Western blot. The presence of reverse transcriptase (RT) and p24 antigen was investigated in the concentrate supernatant of the culture. The DNA of all studied patients was submitted to polymerase chain reaction and Southern blot analysis using primers and probes recognizing the tax region of HTLV-1/2 and the pol region of HTLV-1. 10 of 29 patients were found positive to HTLV-1, whereas they were always negative to RT and p24. The same results were confirmed in double blind after 6 mo. Our findings suggest HTLV-1 may be involved in the etiology of MF, at least in certain cases.

Cutaneous disease resembling mycosis fungoides in HIV-infected patients whose skin and blood cells also harbor proviral HTLV type I

Two homosexual HIV-infected patients with lymphocyte counts of < 50 presented with intense pruritus, hyperpigmentation, and skin lesions clinically suggestive of the cutaneous T cell lymphoma, mycosis fungoides. On light microscopy, the skin biopsies were difficult to interpret because of the sparseness of the lymphocytic infiltrates. However, electron microscopy revealed typical Sézary cells in the peripheral blood and skin. Cultures of blood mononuclear cells of one of the patients generated HTLV-I-like particles. Although both patients lacked antibodies to HTLV, their blood and skin specimens proved to harbor tax and pol HTLV-I proviral sequences as shown by the polymerase chain reaction and Southern blot analysis. Dual infection with HIV and HTLV should be considered in the diagnostic work-up of patients at risk, even in the absence of demonstrable antibodies. Dual infections could result in clinical manifestations and evolution of disease not anticipated in patients who harbor only one of these retroviruses.

Effect of p40tax trans-activator of human T cell lymphotropic virus type I on expression of autoantigens

The possibility of a retroviral etiology has long been raised in a number of autoimmune disorders. More recently, Sjögren's syndrome and rheumatoid arthritis were noted in transgenic mice carrying the tax gene of human T cell leukemia virus type I (HTLV-I). To evaluate the involvement of HTLV-I Tax in autoimmunity, its effect on expression of autoantigens was investigated. A metallothionein promoter-driven p40tax expression plasmid, pMAXRHneo-1, was stably transfected into Molt4 and Jurkat cells and the p40tax protein was induced with CdCl2. trans-Activation or trans-repression of autoantigens by HTLV-I Tax was studied by Western blot analysis utilizing autoantigen-specific murine monoclonal and rabbit polyvalent antibodies as well as sera from 161 autoimmune patients. Induction of p40tax of HTLV-I had no significant effect on levels of expression of common autoantigens U1 snRNP, Sm, Ro, La, HSP-70, topoisomerase I/Scl70, PCNA, and HRES-1. Expression of two potentially novel autoantigens, 44 and 46 kDa, was induced by p40tax as detected by sera of progressive systemic sclerosis patients, BAK and VAR. By contrast, expression of 24- and 34-kDa proteins was suppressed in response to induction of p40tax as detected by sera of systemic lupus erythematosus patients PUS and HOR. Because none of these patients were infected by HTLV-I, a protein functionally similar to p40tax may be involved in eliciting autoantigen expression and a subsequent autoantibody response in a minority of patients with PSS and SLE. Sera of autoimmune patients may also be utilized to detect novel proteins trans-activated or trans-repressed by p40tax of HTLV-I.