Characterization and distribution of nucleic acid sequences of a novel type C retrovirus isolated from neoplastic human T lymphocytes

Anti-Human T-Cell Leukemia Virus Type 1 (HTLV-1) Antibody Assays in Cerebrospinal Fluid for the Diagnosis of HTLV-1-Associated Myelopathy/Tropical Spastic Paraparesis

The anti-human T-cell leukemia virus type 1 (HTLV-1) antibody assay in common use has changed from the particle agglutination (PA) method to chemiluminescent immunoassay (CLIA) and chemiluminescent enzyme immunoassay (CLEIA). These assays were validated in serum but not in cerebrospinal fluid (CSF). However, anti-HTLV-1 antibody positivity in CSF is a requisite for diagnosing HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). We qualitatively compared the assays in CSF from 47 HAM/TSP patients diagnosed using PA, 15 HTLV-1 carriers (HCs), and 18 negative controls. In determining the positivity or negativity of CSF anti-HTLV-1 antibodies, we used serum cutoff points for CLIA and CLEIA because CSF cutoff points had not been decided. Truth table analysis revealed that the performance of CLIA was closer to that of PA and that CLEIA had low sensitivity. CSF antibodies from HAM/TSP patients were all positive by PA and CLIA but 83.0% positive by CLEIA. CSF antibodies from HCs were positive in 73.3%, 80.0%, and 6.7% by PA, CLIA, and CLEIA, respectively. Receiver operator characteristic curve analysis for CSF revealed that with the default cutoff point used for serum, CLIA and PA had comparable performances and CLEIA was less sensitive. The best performances of CLIA and CLEIA with adjusted cutoff points were 94.8% sensitivity and 95.5% specificity and 89.7% sensitivity and 95.5% specificity, respectively. We conclude that low-sensitivity CLEIA can underdiagnose HAM/TSP and that CLIA is a better alternative to PA in anti-HTLV-1 antibody assay for CSF with the current cutoff points.

The discovery of HTLV-1, the first pathogenic human retrovirus

After the discovery of retroviral reverse transcriptase in 1970, there was a flurry of activity, sparked by the "War on Cancer," to identify human cancer retroviruses. After many false claims resulting from various artifacts, most scientists abandoned the search, but the Gallo laboratory carried on, developing both specific assays and new cell culture methods that enabled them to report, in the accompanying 1980 PNAS paper, identification and partial characterization of human T-cell leukemia virus (HTLV; now known as HTLV-1) produced by a T-cell line from a lymphoma patient. Follow-up studies, including collaboration with the group that first identified a cluster of adult T-cell leukemia (ATL) cases in Japan, provided conclusive evidence that HTLV was the cause of this disease. HTLV-1 is now known to infect at least 4-10 million people worldwide, about 5% of whom will develop ATL. Despite intensive research, knowledge of the viral etiology has not led to improvement in treatment or outcome of ATL. However, the technology for discovery of HTLV and acknowledgment of the existence of pathogenic human retroviruses laid the technical and intellectual foundation for the discovery of the cause of AIDS soon afterward. Without this advance, our ability to diagnose and treat HIV infection most likely would have been long delayed.

Demographic patterns of cutaneous T-cell lymphoma incidence in Texas based on two different cancer registries

Cutaneous T-cell lymohomas (CTCLs) are rare, but potentially devastating malignancies, with Mycosis fungoides and Sézary Syndrome being the most common. In our previous study, we identified and described regions of geographic clustering of CTCL cases in Texas by analyzing ∼1990 patients using two distinct cancer registries. In the current work, we describe in detail demographic patterns for this malignancy in our study population and apply logistic regression models to analyze the incidence of CTCL by sex, race, age, and clinical stage at the time of diagnosis. Furthermore, using Fisher's exact test, we analyze changes in incidence over time in the identified Houston communities with unusually high CTCL incidence. While CTCL primarily affects Caucasian individuals >55 years old, we confirm that it presents at a younger age and with more advanced disease stages in African-American and Hispanic individuals. Also, we demonstrate a significant increase in CTCL incidence over time in the identified communities. Spring, Katy, and Houston Memorial areas had high baseline rates. Furthermore, a statistically significant disease surge was observed in these areas after ∼2005. This report supplements our initial study documenting the existence of geographic clustering of CTCL cases in Texas and in greater detail describes demographic trends for our patient population. The observed surge in CTCL incidence in the three identified communities further argues that this malignancy may be triggered by one or more external etiologic agents.

Identification of geographic clustering and regions spared by cutaneous T-cell lymphoma in Texas using 2 distinct cancer registries

BACKGROUND

Cutaneous T-cell lymphomas (CTCLs) (mycosis fungoides and its leukemic variant, Sezary syndrome) are rare malignancies. Reports of the occurrence of mycosis fungoides in married couples and families raise the possibility of an environmental trigger for this cancer. Although it has been suggested that CTCL arises from inappropriate T-cell stimulation, to the authors' knowledge no preventable trigger has been identified to date.

METHODS

Using region, zip code, age, sex, and ethnicity, the authors analyzed the demographic data of 1047 patients from Texas who were seen in a CTCL clinic at The University of Texas MD Anderson Cancer Center during 2000 through 2012 (the MDACC database) and 1990 patients who were recorded in the population-based Texas Cancer Registry between 1996 and 2010. Subsequently, data from both databases were cross-analyzed and compared.

RESULTS

The current study findings, based on the MDACC database, documented geographic clustering of patients in 3 communities within the Houston metropolitan area, in which CTCL incidence rates were 5 to 20 times higher than the expected population rate. Analysis of the Texas Cancer Registry database defined the CTCL population rate for the state to be 5.8 cases per million individuals per year (95% confidence interval, 5.5-6.0 per million individuals per year), thus confirming the observations from the MDACC database and further highlighting additional areas of geographic clustering and regions spared from CTCL in Texas.

CONCLUSIONS

The current study documented geographic clustering of CTCL cases in Texas and argued for the existence of yet unknown external causes/triggers for this rare malignancy.

Research and discovery of the first human cancer virus, HTLV-1

Human T-cell lymphoma virus (HTLV)-1 was the first human retrovirus to be discovered. It has been recognized as the cause of adult T-cell leukemia (ATL). In addition to giving a historical perspective on HTLV-1 and other retrovirus research, this paper discusses the origin of HTLV-1; the modes of transmission and global epidemiology of HTLV-1 infection; the genome of HTLV-1 and the mechanism of HTLV-1-induced leukemogenesis; the role of HTLV-1 in other diseases, and recent breakthroughs in ATL therapy.

The antiproliferative effect of kefir cell-free fraction on HuT-102 malignant T lymphocytes

Kefir is produced by adding kefir grains (a mass of proteins, polysaccharides, bacteria, and yeast) to pasteurized milk; it has been shown to control several cellular types of cancer, such as Sarcoma 180 in mice, Lewis lung carcinoma, and human mammary cancer. Human T-cell lymphotropic virus type 1 (HTLV-1) is the causative agent of adult T-cell leukemia, which is a fatal disease with no effective treatment. The current study aims at investigating the effect of a cell-free fraction of kefir on HuT-102 cells, which are HTLV-1-positive malignant T-lymphocytes. Cells were incubated with different kefir concentrations: the cytotoxicity of the compound was evaluated by determining the percentage viability of cells. The effect of all the noncytotoxic concentrations of kefir cell-free fraction on the proliferation of HuT-102 cells was then assessed. The levels of transforming growth factor (TGF)-alpha mRNA upon kefir treatment were then analyzed using reverse transcriptase polymerase chain reaction. Finally, the growth inhibitory effects of kefir on cell cycle progression and/or apoptosis were assessed by flow cytometry. The maximum cytotoxicity recorded at 80 microg/microL for 48 hours was only 43%. The percent reduction in proliferation was very significant, dose and time dependent, and reached 98% upon 60-microg/microL treatment for 24 hours. Kefir cell-free fraction caused the downregulation of TGF-alpha, which is a cytokine that induces the proliferation and replication of cells. Finally, a marked increase in cell cycle distribution was noted in the pre-G1 phase. In conclusion, kefir is effective in inhibiting proliferation and inducing apoptosis of HTLV-1-positive malignant T-lymphocytes. Therefore, further in vivo investigation is highly recommended.

Adult T-cell Leukemia/Lymphoma: First case report from Qatar

In what appears to be the first case of Adult T-cell Leukemia|Lymphoma (ATLL) reported in Qatar and Middle Eastern Arab countries, a 39-year-old lady presented first with Pneumocystis carinii pneumonia and hypercalcaemia and later showed the full picture of ATLL, splenomegaly leukocytosis, skin rash, and bone marrow infiltrations. She responded well to chemotherapy, with complete remission after four cycles of combination chemotherapy but the prognosis of patients with ATLL is poor. Although patients may respond initially to treatment with combination chemotherapy regimens devised for advanced, aggressive Non-Hodgkin's Lymphoma (NHL), relapses are common with a median survival of eight months and a four-year survival of 12 percent.

A novel alternative splicing isoform of human T-cell leukemia virus type 1 bZIP factor (HBZ-SI) targets distinct subnuclear localization

Adult T-cell leukemia (ATL) is associated with prior infection with human T-cell leukemia virus type 1 (HTLV-1); however, the mechanism by which HTLV-1 causes adult T-cell leukemia has not been fully elucidated. Recently, a functional basic leucine zipper (bZIP) protein coded in the minus strand of HTLV-1 genome (HBZ) was identified. We report here a novel isoform of the HTLV-1 bZIP factor (HBZ), HBZ-SI, identified by means of reverse transcription-PCR (RT-PCR) in conjunction with 5' and 3' rapid amplification of cDNA ends (RACE). HBZ-SI is a 206-amino-acid-long protein and is generated by alternative splicing between part of the HBZ gene and a novel exon located in the 3' long terminal repeat of the HTLV-1 genome. Consequently, these isoforms share >95% amino acid sequence identity, and differ only at their N termini, indicating that HBZ-SI is also a functional protein. Duplex RT-PCR and real-time quantitative RT-PCR analyses showed that the mRNAs of these isoforms were expressed at equivalent levels in all ATL cell samples examined. Nonetheless, we found by Western blotting that the HBZ-SI protein was preferentially expressed in some ATL cell lines examined. A key finding was obtained from the subcellular localization analyses of these isoforms. Despite their high sequence similarity, each isoform was targeted to distinguishable subnuclear structures. These data show the presence of a novel isoform of HBZ in ATL cells, and in addition, shed new light on the possibility that each isoform may play a unique role in distinct regions in the cell nucleus.

History of the discoveries of the first human retroviruses: HTLV-1 and HTLV-2

HTLV-1 was discovered in the US in 1979, and published in 1980. This was rapidly followed by four additional reports in early 1981 describing additional isolates, characterization of some of the HTLV-1 proteins, serological assays for specific antibodies indicative of HTLV-1 infection, and evidence for integrated DNA proviruses in infected cells. None of this early work was dependent upon or influenced by the subclassification of some T-cell malignancies as ATL (in Japan). Instead, I was stimulated by prior work from many investigators in the US and Europe on retroviruses which caused leukemia in animals and our discoveries were made possible by our technical approaches developed in the 1970s involving especially sensitive assays for RT as a surrogate marker for a retrovirus and our discovery of Il-2 which made it possible to culture human T cells. However, following our reports the same virus was isolated in Japan, and both groups provided evidence that HTLV-1 caused ATL, a subclassification of T-cell malignancies first recognized in Japan.

Human retroviruses in leukaemia and AIDS: reflections on their discovery, biology and epidemiology

The study of retroviruses has had a profound impact by unveiling an unusual form of viral replication: the multiplication of RNA viruses via a proviral DNA, for which Jan Svoboda provided the experimental model over forty years ago. In 1970 Temin, Mizutani and Baltimore discovered that this group of viruses contains a unique enzyme catalysing the synthesis of a DNA copy of the viral RNA: reverse transcriptase (RT). The discovery of RT has itself had an enormous impact on molecular biology in general, but also stimulated many premature claims of its detection in human disease. Claims by Gallo's laboratory that the cytoplasm of human leukaemia cells contained RT proved to be unfounded, as did his report in collaboration with Weiss that myeloid leukaemia contained HL23 virus, this organism proving not to be human but a laboratory contaminant of three monkey viruses. Conclusive demonstration of a retroviral involvement in human leukaemia was first provided in 1981 by Hinuma and his associates, showing that adult T-cell leukaemia (ATL), a rare form of leukaemia endemic to south-west Japan, is caused by a new retrovirus (ATLV). Other publications in December 1980 and through 1981 claimed the discovery of a new human T-cell leukaemia virus involved in mycosis fungoides (MF) and Sézary's syndrome (SS). This virus was termed HTLV by Gallo. The nucleotide sequence of ATLV is strongly conserved, that of my 1983 isolate from a black British ATL patient being practically identical with the Japanese virus isolates. After AIDS was recognised in 1981 by Gottlieb and coworkers as a new human disease, several papers were published by Gallo and his associates during 1983-4, invoking the oncovirus responsible for adult T-cell leukaemia as the cause of AIDS. In 1983 the French scientist Barré-Sinoussi and her colleagues succeeded in isolating a new agent in the disease, a lentivirus, which they named LAV. The French immunologist Klatzmann and his colleagues discovered that LAV killed CD4+ T-cells, furnishing an explanation for the pathogenesis of AIDS and providing a mechanism for how AIDS developed. For some time Gallo continued to suggest leukaemia virus involvement, claiming that his independent isolate of the AIDS virus, termed HTLV-III, was closely related to HTLV-I (the Japanese ATLV). Although this created considerable confusion among researchers for a period, the relationship was eventually disproved. Unlike ATLV, whose nucleic acid sequence is very stable, the AIDS virus (now termed HIV by international agreement) is extraordinarily unstable, the sequences of independent HIV isolates being quite unique: this made it possible to establish conclusively that both HTLV-III and another independent isolate CBL-1, from Weiss' laboratory, were actually LAV isolates from the French laboratory. It has been shown by Hayami and his associates that only African primates are infected with similar lentiviruses to HIV which explains why AIDS started in Africa. Further research has clarified the origin of HIV-1 to be a chimpanzee lentivirus and HIV-2 to be the sooty mangabey lentivirus, which began to spread in humans perhaps no more than fifty years ago. The infection has spread rapidly, primarily through sexual intercourse, but also by transmission through blood and its products as well as contaminated needles and syringes. Sexual intercourse has now spread the virus around the World; and there are probably some 70 million infected. 90% of those infected with HIV develop the deadly disease of AIDS within ten years of infection: the death toll from the disease has been enormous. By contrast, HTLV-1 has been infecting man in isolated areas probably for hundreds of years; but it has not spread widely. HTLV causes leukaemia in only less than 1% of those infected. The prime mode of transmission of HTLV-1 is between mother and neonate; infections can be reduced by stopping breast-feeding by infected mothers. The isolation of HIV enabled screening tests to be developed for contaminated blood. However, due to the peculiar biology of HIV infection, unfortunately all efforts to develop an effective vaccine have so far failed.

The discovery of the first human retrovirus: HTLV-1 and HTLV-2

I describe here the history leading up to and including my laboratory's discovery of the first human retrovirus, HTLV-I, and its close relative, HTLV-II. My efforts were inspired by early work showing a retroviral etiology for leukemias in various animals, including non-human primates. My two main approaches were to develop criteria for and methods for detection of viral reverse transcriptase and to identify growth factors that could support the growth of hematopoietic cells. These efforts finally yielded success following the discovery of IL-2 and its use to culture adult T cell lymphoma/leukemia cells.

Clear cell sarcoma associated with multiple pulmonary metastases with structural and numerical karyotypic changes

Cytogenetic analysis was performed on a specimen from a pulmonary metastasis of clear cell sarcoma originated on the right ankle of a 53-year-old Japanese woman. It revealed near-triploid with several numerical changes including abnormalities in the copy number of chromosomes 7, 8, and 22, and structural abnormalities of chromosome 22 and others. This is a minor case which showed the multiple abnormalities of chromosomes in the absence of a t (12;22) translocation.

ABCs of radioisotopes used for radioimmunotherapy: alpha- and beta-emitters

Although the introduction of the monoclonal antibody rituximab 5 years ago led to a marked improvement in the treatment of non-Hodgkin's lymphoma (NHL), most patients do not experience a complete response to therapy, and many who do respond relapse. One way of improving the efficacy of monoclonal antibodies is to use them to deliver cytotoxic agents, such as radionuclides, to the tumor. Monoclonal antibodies armed with radionuclides provide a means of targeting radiation therapy specifically to tumor cells that express the antigen to which the antibody was originally raised. Subsequently, in 2002, the first radiolabeled monoclonal antibody, 90Y-ibritumomab tiuxetan was approved for the treatment of patients with relapsed or refractory low-grade follicular or transformed B-cell NHL, including patients with follicular lymphoma refractory to rituximab. Attempts to optimize the efficacy of radioimmunotherapy are ongoing, however, and there are three factors that need to be considered: choice of antibody/antigen, choice of delivery of system to be used, and choice of radionuclide. CD25 (IL-2R alpha) is an ideal choice for a target antigen as it is over-expressed by a number of tumor cells, including adult T-cell leukemia (ATL); 9 of 16 patients with ATL responded to treatment with anti-Tac (which targets the interleukin-2 receptor-alpha [IL-2R alpha]), conjugated to 90Y. The dose of radionuclide that can be delivered to a tumor can be increased dramatically by using a three-step process in which the antibody and radioactivity are delivered separately to the antigen in order to improve tumor-to-normal tissue ratios. The most commonly used radionuclides in radioimmunotherapy to date are beta-emitters. However, the pretargeting process makes the use of short-lived alpha-emitters more feasible. The results of experiments involving this pretargeting process and alpha- and beta-emitting radionuclides in leukemia and lymphoma models suggest that alpha-emitters may be more effective in the treatment of small tumors, micrometastases and isolated cells, and that beta-emitters may be more suitable for use in large tumor masses, such as lymphomas.

An Alternative Transcript Derived from the Trio Locus Encodes a Guanosine Nucleotide Exchange Factor with Mouse Cell-transforming Potential

By screening cDNA expression libraries derived from fresh leukemic cells of adult T-cell leukemia for the potential to transform murine fibroblasts, NIH3T3, we have identified a novel transforming gene, designated Tgat. Expression of Tgat in NIH3T3 resulted in the loss of contact inhibition, increase of saturation density, anchorage-independent growth in a semisolid medium, tumorigenicity in nude mice, and increased invasiveness. Sequence comparison revealed that an alternative RNA splicing of the Trio gene was involved in the generation of Tgat. The Tgat cDNA encoded a protein product consisting of the Rho-guanosine nucleotide exchange factor (GEF) domain of a multifunctional protein, TRIO, and a unique C-terminal 15-amino acid sequence, which were derived from the exons 38-46 of the Trio gene and a novel exon located downstream of its last exon (exon 58), respectively. A Tgat mutant cDNA lacking the C-terminal coding region preserved Rho-GEF activity but lost the transforming potential, indicating an indispensable role of the unique sequence. On the other hand, treatment of Tgat-transformed NIH3T3 cells with Y-27632, a pharmacological inhibitor of Rho-associated kinase, abrogated their transforming phenotypes, suggesting the coinvolvement of Rho-GEF activity. Thus, alternative RNA splicing, resulting in the fusion protein with the Rho-GEF domain and the unique 15 amino acids, is the mechanism generating the novel oncogene, Tgat.

Human retroviruses after 20 years: a perspective from the past and prospects for their future control

Among viruses the human retroviruses may be of special interest to immunologists, because they target cells of the immune system, particularly mature CD4+ T cells, impair their function and cause them to grow abnormally (human T-cell leukemia virus, HTLV) or to die (human immunodeficiency virus, HIV). Human retroviruses cause disease ranging from neurological disorders and leukemias (HTLV-1) to AIDS (acquired immunodeficiency virus) (HIV) and promote development of several types of malignancies (HIV). They share many common features, but their contrasts are greater, especially the far greater replication and variation of HIV associated with its greater genomic complexity. Both have evolved striking redundancy for mechanisms which promote their survival. Thus, HTLV has redundant mechanisms for promoting growth of provirus containing T cells needed for virus continuity, because it is chiefly through its cellular DNA provirus that HTLV replicates and not through production of virions. Conversely, HIV has redundancy in its mechanisms for promoting virion replication and escape from the host immune system. It is via these redundant mechanisms that they produce disease: leukemias from mechanisms promoting T-cell proliferation (HTLV-1) and AIDS from mechanisms promoting virus replication and T-cell death (HIV). The practical challenges for the future are clear. For HTLV-1, education and control of breastfeeding. For HIV, the formidable tasks now ahead in part demand new kinds of talent, talents that will foster greater insights into the development of therapy for the developing countries, new forms of less toxic therapies for all infected persons, a continued and expanded commitment to education, and a persistent 'never say die' commitment to the development of a truly preventive vaccine with all the scientific and nonscientific challenges that these objectives face.

HTLV-1-mediated immunopathological CNS disease

HAM/TSP is a chronic inflammatory disease of the spinal cord. It is rather rare in HTLV-1-infected individuals. Immunogenetic factors of the HLA complex have been identified that support or prevent the development of the disease. In HAM/TSP patients a characteristic constellation of high proviral loads and increased cellular and humoral immune responses have been established. Immune dysfunction in HAM/TSP patients might be partly explained by HTLV-1 tax p40 transactivation of cellular genes in infected CD4+ T lymphocytes. The oligoclonal expansion of infected T lymphocytes, the variation of tax p40 within HTLV-1 carriers, and the regulation of proviral gene expression are possible determinants for disease development and need to be clarified in future studies.

Advances in interleukin 2 receptor targeted treatment

T cell activation and cellular immune responses are modulated by interleukin 2 (IL2) through binding to its corresponding cell surface receptor. Three forms of the receptor are recognised based on IL2 binding affinity. The high affinity receptor is a heterotrimer composed of alpha, beta, and gamma(c)-polypeptide chains. The 55 kDa alpha-chain also known as the Tac (T cell activation) antigen or CD-25 is a unique subunit of the high affinity IL2 receptor (IL2Ralpha). Resting T cells express few IL2Ralpha, however, when activated, the expression of ILR2alpha rapidly increases. The IL2Ralpha is shed from the cell surface and is measurable in the serum as a 45 kDa soluble form (s-Tac or s-IL2Ralpha). Serum concentrations of s-Tac can be used as a surrogate marker for T cell activation and IL2Ralpha expression. IL2Ralpha is over expressed by T cells in a number of autoimmune diseases, allograft rejection and a variety of lymphoid neoplasms. IL2 induced proliferation of T cells can be inhibited by the murine monoclonal antibody (anti-Tac) directed against the alpha-chain of the IL2R. Through molecular engineering, murine anti-Tac has been humanised reducing its immunogenicity without changing its specificity. Humanised anti-Tac (HAT) has been shown to reduce the incidence of renal and cardiac allograft rejection as well as decrease the severity of graft versus host disease in patients undergoing HLA matched allogeneic bone marrow transplantation. IL2Ralpha targeted treatment with radioimmunoconjugates of anti-Tac and immunotoxins has shown promise in the treatment of CD25 expressing lymphomas.

Treatment of adult T-cell leukemia-lymphoma with a combination of interferon alfa and zidovudine

BACKGROUND

Infection with the human T-cell lymphotropic virus type I, a retrovirus, can cause a distinctive cancer, adult T-cell leukemia-lymphoma. The median survival of patients with the acute and lymphomatous forms of the disease is short, despite the use of cytotoxic chemotherapy.

METHODS

We treated 19 patients with acute or lymphomatous forms of adult T-cell leukemia-lymphoma with oral zidovudine (200 mg five times daily) and interferon alfa (Intron A, 5 to 10 million units subcutaneously each day). Seven of these patients had either relapsed after multiagent cytotoxic chemotherapy or failed to respond to that treatment.

RESULTS

Major responses were achieved in 58 percent of the patients (11 of 19), including complete remission in 26 percent (5 of 19). Four patients in whom prior cytotoxic therapy had failed had major responses, two of which were complete remissions. Six patients have survived for more than 12 months, with the longest remission since the discontinuation of treatment lasting more than 59 months.

CONCLUSIONS

The combination of zidovudine and interferon alfa has activity against adult T-cell leukemia-lymphoma, even in patients in whom prior cytotoxic therapy has failed. This regimen should be evaluated further for its role in the treatment of adult T-cell leukemia-lymphoma.

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.

Autopsy findings in 47 cases of adult T-cell leukemia/lymphoma in Miyazaki prefecture, Japan

To identify factors that might improve the prognosis of adult T-cell leukemia/lymphoma (ATL), we reviewed data on 47 autopsied cases of ATL with reference to the complications and cause of death. The primary cause of death was respiratory insufficiency due to pulmonary infection. Respiratory insufficiency was also attributed to the diffuse alveolar damage and pulmonary fibrosis resulting from chemotherapy given and oxygen. About 90% of the cases had infections with one or more pathogens. Cytomegalovirus (CMV) was the most frequent pathogen involved in 35/47 (74.5%) while fungal infections were also commonly seen in 25 of the 47 cases (53.2%). Of these, 17 (70%) had pulmonary aspergillosis. Other neoplasias were present in 10 of the 47 cases, while hypercalcemia was evident in 21 patients. These findings suggest that the prevention and treatment of nosocomial infections and of drug-induced pulmonary toxicity may improve the prognosis and quality of life of ATL patients.

Primary T-cell lymphoma of the gastrointestinal tract associated with human T-cell lymphotropic virus type I. An analysis using in situ hybridization and polymerase chain reaction

BACKGROUND

During a population-based local cancer registry, a peculiar type of T-cell lymphoma restricted to the gastrointestinal tract was found in patients living in southwestern Japan.

METHODS

Five cases of gastrointestinal (GI) tract T-cell lymphoma were analyzed with immunohistologic examination, ultrastructural analysis, in situ hybridization (ISH), and polymerase chain reaction (PCR).

RESULTS

All cases satisfied the criteria of primary GI tract lymphoma at presentation or operation. Four showed a close relationship to human T-cell lymphotropic virus type I (HTLV-I). Those four had positive results for anti-HTLV-I antibody and positive surface markers for CD4, positive hybridization signals by ISH, and HTLV-I gene products by PCR, but they had no lymphoma cells in peripheral blood or bone marrow. The fifth case showed negative signals by ISH and PCR.

CONCLUSIONS

These findings suggest that some of the putative adult T-cell leukemia/lymphoma (ATLL) types can be further classified as GI-tract-type lymphoma. The prognosis for the GI tract type is as poor as it is for conventional ATLL.

Human T-cell leukemia virus-1-positive cell line established from a patient with small cell lung cancer

A stable cell line, KHM-3S, was established from a patient with small cell lung cancer (SCLC), who had a high serum level of soluble interleukin 2 receptors (sIL2-R) and was seropositive for human T cell leukemia virus (HTLV)-1. KHM-3S cells were positive for IL2-R (Tac) and NKH-1, but negative for other lymphocytic markers such as OKT 11, OKT 4, OKT 8, T cell receptor (WT 31), B 1, and B 4. Moreover, the KHM-3S cells were negative for leukocyte common antigen and strongly positive for neuron-specific enolase (NSE). Secretion of sIL2-R and NSE by the KHM-3S line was detected by an enzyme-linked immunosorbent assay. Rearrangement of the T cell receptor gene and monoclonal HTLV-1 integration were found by Southern blot analysis of KHM-3S DNA. However, Northern blot analysis showed no T cell receptor mRNA. KHM-3S may be useful for studies on the role of HTLV-1 in carcinogenesis and IL2-R expression in SCLC.

Adult T-cell leukemia: structures and expression of the p53 gene

Experiments were undertaken to investigate a genetic event involved in leukemogenesis in adult T-cell leukemia (ATL). For this purpose, the p53 gene was chosen for study, since alteration of the gene has been found in a wide variety of human cancers. Structures and expression of the p53 gene in ATL cells were investigated by Southern and Northern blot analyses and a polymerase-chain-reaction single-strand conformation-polymorphism (PCR-SSCP) analysis. Either subtle alterations of the p53 gene or the absence of detectable level of p53 mRNA were found in 2 of 3 acute ATL cell lines and 2 of 12 acute ATL fresh samples. In contrast, no mutation was detected in 4 cases with less aggressive types of ATL (3 chronic and 1 smoldering ATL cases). Mutations found in acute ATL cells occurred in regions highly conserved in evolution and all the cells carrying p53 mutation showed loss of the other p53 allele. These results suggests that alteration of the p53 gene may contribute to progression of the disease in some cases of ATL.

Human T-cell leukemia virus type 1 associated with small cell lung cancer

A patient with small cell lung cancer (SCLC) whose serum contained high levels of soluble interleukin-2 receptors is reported. Soluble interleukin-2 receptors in the supernatant of cultured SCLC cells obtained from the patient's pleural effusion while he had malignant pleuritis, increased almost linearly from the time of cell seeding. The expression of interleukin-2 receptors (Tac) on the SCLC cells were demonstrated by an immunofluorescence study. However, other lymphocytic markers, including OKT 11, OKT 4, OKT 8, B 1, and B 4, were not found on the cells with the exception of the natural killer cell marker, NKH-1. Southern blot analysis indicated the rearrangement of the T-cell receptor of the cancer cells. Moreover, monoclonal integration of human T-cell leukemia virus type 1 (HTLV-1) provirus in DNA from the cancer cells was also demonstrated. These observations suggest that some SCLC in HTLV 1 endemic areas are associated with HTLV-1.

Anti-human immunodeficiency virus effects of dextran sulfate are strain dependent and synergistic or antagonistic when dextran sulfate is given in combination with dideoxynucleosides

The effects of three molecular weight ranges of dextran sulfate on five different human immunodeficiency virus (HIV) isolates (from patients with acquired immunodeficiency syndrome), alone and in combination with dideoxynucleosides, were investigated in vitro. The higher the molecular weight range of dextran sulfate, the more potent the activity as assessed by a quantitative syncytium formation assay. Although all five HIV isolates had similar susceptibilities to the inhibitory effects of dideoxynucleosides, the two clinical isolates of HIV (HIV type 1 [HIV-1] TM and SP) exhibited a pattern of reduced susceptibility to dextran sulfate when compared with the two cloned isolates (HIV-1 WMF and HIV-2 ROD) and a prototype laboratory strain (HIV-1 IIIB). In combination with dideoxynucleosides, the high-molecular-weight range of dextran sulfate (500,000) resulted in an antagonistic response directed against the two clinical isolates of HIV (HIV-1 TM and SP) when the antiviral concentrations of dextran sulfate were in the ineffective range. Additive or synergistic effects were seen with the other three HIV isolates and all five HIV isolates when the low-molecular-weight range of dextran sulfate (8,000) was used. The results of these studies raise issues on the impact of drug-resistant strains on disease progression and the use of dextran sulfate in combination with nucleoside analogs for the clinical management of HIV disease.

Cellular pharmacology and anti-HIV activity of 2',3'-dideoxyguanosine

The antiviral activity, uptake, and metabolism of 2',3'-dideoxyguanosine was investigated in human immunodeficiency virus- (HIV) infected and noninfected human cells. 2',3'-Dideoxyguanosine had anti-HIV activity (effective dose 50%: 0.1-1.0 microM) in H-9 and MT-2 cells. The addition of excess (greater than or equal to 30 microM) guanosine, deoxyguanosine, or 8-aminoguanosine had no effect on the anti-HIV activity of 2',3'-dideoxyguanosine. In [8-3H]2',3'-dideoxyguanosine-exposed cells, the intracellular radioactivity was twofold higher than the extracellular. When guanosine, deoxyguanosine, or 8-aminoguanosine was preincubated or added simultaneously to 2',3'-dideoxyguanosine, uptake of 2',3'-dideoxyguanosine was reduced by 28 to 34%, whereas addition of p-nitrobenzylmercaptopurine riboside (20 microM) had no effect. In metabolism studies using H-9 cells, dideoxyguanosine triphosphate could not be detected despite a 24-h incubation of 2',3'-dideoxyguanosine at effective anti-HIV concentrations. The addition of excess (greater than or equal to 30 microM) guanosine, deoxyguanosine, and 8-aminoguanosine, while inhibiting the catabolism of 2',3'-dideoxyguanosine, did not enhance the anabolic conversion of 2',3'-dideoxyguanosine to dideoxyguanosine triphosphate. Our failure to detect the formation of dideoxyguanosine triphosphate and the lack of reversal of antiviral effects by natural purine nucleosides raises questions on the role of this metabolite in the anti-HIV activity of 2',3'-dideoxyguanosine.

Discordance between phenotype and function of Japanese adult T cell leukemia cells

Phenotypes of cells from 12 patients with ATL were analysed by means of a fluorescence-activated cell sorter by utilizing a panel of monoclonal antibodies. A majority of the cells from peripheral blood coexpressed the antigens against MAbs CD2, CD3, CD4, CD5, Ti (WT31), CD25, CD38, CD45, and CD29, but did not express the antigens against CD1, CD13, CD14, CD33, CD36, CD10, CD19, CD20, CD21, CD24, CD41, CD42, CD45RA, CD56, and CD57. The expression of antigen for TQ-1 or Leu8 was variable. Surface immunoglobulins were not detected. Phenotypes of cultured cells established by utilizing recombinant interleukin II were similar to those of the uncultured peripheral blood lymphoid cells except for the lack of expression of CD8. By means of two-color fluorescence, the ATL cells possessing CD4 in peripheral blood and culture coexpressed CD29, but did not express CD45RA. The suppression of PWM-induced B-cell immunoglobulin synthesis by normal T and B cells was found in five cases in the presence of ATL cells. The ATL cells demonstrated helper T-cell phenotypes (CD4+, CD29+) with suppressor function, paradoxically. We conclude that the phenotype of the ATL cells was CD4+, CD29+, and CD45RA- but that the function of these cells was of suppressor T-cells. Our results inevitably suggest the possible existence of suppressor T-cells with CD4+, CD29+ phenotype in persons without evidence of any underlying hematologic disorder.

Retrovirus-associated adult T-cell leukemia-lymphoma: an epidemiologic study of five cases among Hawaii-born offspring of migrant Japanese

Adult T-cell leukemia-lymphoma (ATLL) is a distinct clinicopathologic entity etiologically linked to HTLV-I infection. We have identified five cases of retrovirus-associated ATLL among Hawaii-born first generation offspring (nisei) of migrant Japanese. Four patients were offspring of migrant Japanese (issei) who emigrated to Hawaii from Okinawa, an HTLV-I endemic area. The fifth patient was born of parents who emigrated to Hawaii from Fukushima and Miyagi prefectures, HTLV-I nonendemic areas. Epidemiologic implications and family studies with regard to HTLV-I antibody testing of the index cases are discussed. The high rate of HTLV-I antibody seropositivity among family members and relatives indicates that the risk of acquiring HTLV-I infection and of developing ATLL persists long after migration. Documentation of ATLL among offspring of Japanese immigrants to Hawaii is an important observation because it confirms the potential for long latency between putative exposure to virus and the development of overt disease. Changing marriage patterns among the Hawaii-Japanese may weaken the risk of vertical virus transmission to the descendents of migrants from southern Japan, while increasing the risk to children born of mixed marriages. In addition, blood products derived from high-risk donors will constitute a continuing hazard if they are not subject to screening.

Nucleotide dimers suppress HIV expression in vitro

A series of nucleotide homo- and heterodimers [3'-azido-3'-deoxythymidilyl-(5',5')-2',3'-di-deoxy-5' adenylic acid (AZT-P-ddA), 3'-azido-3'-deoxythymidilyl-(5',5')-2', 3'-dideoxy;-5'-adenylic acid, 2-cyanoethyl ester [AZT-P(CyE)-ddA], 3'-azido-3'-deoxythymidilyl-(5',5')-2',3'-dideoxy-5'-inosinic acid (AZT-P-ddI), and 3'-azido-3'-deoxythymidilyl-(5',5')-3'-azido-3'-deoxy-5'-thymid ilic acid (AZT-P-AZT)] were synthesized and compared with respect to their anti-HIV and cytotoxic properties to their component monomers in vitro. MT-2 cells were infected with HIV (TM) followed by the addition of drug. The dimers and their respective monomers inhibited HIV-induced syncytia formation, reverse transcriptase production, and the expression of HIV p24 antigen. However, on an equimolar basis, greater anti-HIV potency and enhanced cytotherapeutic indices were observed with the heterodimers when compared with their monomers. Nucleotide dimers, such as AZT-P-ddA, should be actively considered for further evaluation as anti-HIV agents.

Polyclonal integration of HTLV-I proviral DNA in lymphocytes from HTLV-I seropositive individuals: an intermediate state between the healthy carrier state and smouldering ATL

We have studied 15 individuals (aged 14-74 years) with antibodies to HTLV-I in their serum and random integration of HTLV-I proviral DNA in their peripheral blood lymphocytes. All but one of these patients suffered from a variety of non-specific complaints which did not correspond to those of adult T-cell leukemia (ATL). All of them were born in Kyushu and Okinawa which are endemic areas for HTLV-I infection; 25% of their family members were also seropositive for HTLV-I. The only haematological abnormality in these patients was the presence of few atypical lymphoid cells in the peripheral blood. The CD4/CD8 ratios were normal but the proportion of Tac positive cells was slightly higher than normal. These individuals with polyclonal integration of HTLV-I proviral DNA seem to represent an intermediate state between smouldering ATL (monoclonal integration) and healthy HTLV-I carriers (with antibodies but no detectable HTLV-I proviral DNA). Patients with this intermediate state of HTLV-I infection may be at risk to progress to ATL. The natural history of HTLV-I infection in humans leading to the development of ATL is reviewed in the light of these new findings.

Serological survey and virus isolation of simian T-cell leukemia/T-lymphotropic virus type I (STLV-I) in non-human primates in their native countries

Infection with a simian retrovirus (STLV-I) closely related to human T-lymphotropic virus type I (HTLV-I) was investigated in non-human primates living in their native countries in Africa and Asia. Serum antibodies cross-reacting with HTLV-I antigens were detected in 85 of 567 non-human primates of 30 species. Seropositive animals were found among African green monkeys, olive baboons, Sykes' monkeys, mandrills and patas monkeys in several countries in Africa, and cynomolgus monkeys, Celebes macaques and siamangs in Indonesia. The frequency of seropositivity was much higher in adult than in young African green monkeys, cynomolgus monkeys and Celebes macaques. STLV-Is were isolated by establishing II lines of virus-producing lymphoid cells in the presence of interleukin-2 from 5 species of seropositive non-human primates, i.e. the African green monkey, Sykes' monkey, Celebes macaque, cynomolgus monkey and siamang. All these cell lines had T-cell markers and Tac antigen, and the cell lines from the African green monkey and Sykes' monkeys were Leu2a+ while those from other species were Leu3a+. These cell lines expressed viral antigens reacting with human sera from adult T-cell leukemia (ATL) patients and monoclonal antibodies (MAbs) against p19 and p24 of HTLV-I core proteins, and produced virus particles having RNA-dependent DNA polymerase activity. Cellular DNAs from these cell lines contained provirus sequences homologous to HTLV-I, shown by Southern blot hybridization. The restriction patterns of these provirus genomes were different from those of HTLV-I and were also dissimilar in the different species.

Pharmacological inhibition of in vitro infectivity of human T lymphotropic virus type I

Human T lymphotropic virus type I (HTLV-I) is an exogenous RNA tumor virus etiologically linked to adult T cell leukemia and related diseases. In this paper, we describe that two 2',3'-dideoxynucleoside analogues, erythro 3'-azido-2',3'-dideoxythymidine (also called azidothymidine) and 2',3'-dideoxycytidine can inhibit the infectivity of HTLV-I against helper/inducer T cells in vitro. Both 2',3'-dideoxynucleoside analogues inhibited the overgrowth of target T cells, which was a consequence of virally mediated transformation, when they were exposed to the virus and cultured with the compounds. A profound decrease in the expression of HTLV-I gag-proteins was also observed. Moreover, we observed that the amount of proviral DNA detected in cellular DNA from the target T cells was substantially reduced when the cells were protected by the compounds against the virus and that at certain concentrations of the compounds the synthesis of viral DNA was completely suppressed. These results may be of value in developing a new pharmacological strategy for preventing the replication and possibly blocking the transmission of HTLV-I and related retroviruses in human beings.

Synergistic inhibition of human immunodeficiency virus in vitro by azidothymidine and recombinant alpha A interferon

Both recombinant alpha A interferon and azidothymidine inhibit the replication of human immunodeficiency virus in peripheral blood mononuclear cells. Combinations of recombinant alpha A interferon and azidothymidine at concentrations that are easily achievable in patients synergistically inhibit human immunodeficiency virus in vitro with minimal toxicity. Combinations of antiretroviral compounds that act by different mechanisms may prove useful in the treatment of acquired immunodeficiency syndrome-related disorders.

Activity of interferons alpha, beta, and gamma against human immunodeficiency virus replication in vitro

The antiviral activities of various interferon preparations against human immunodeficiency virus (HIV) were evaluated in vitro. Recombinant interferon alpha-A, and beta interferons and leukocyte-derived alpha interferons show similar concentration-dependent antiviral activity. Recombinant and lymphocyte-derived gamma interferons show minimal antiviral activity against HIV replication in normal peripheral blood mononuclear cells, but definite activity against HIV in the H9 lymphocytic and U937 monocyte-macrophage cell lines.

Antibodies to HTLV-1 in saliva of seropositive individuals from Japan

Secretory antibodies protect mucosal surfaces against transmission of many viruses. Human T-lymphotropic Virus, Type I (HTLV-I) is transmitted via blood products and via sexual contact across mucosal surfaces. We investigated the presence of HTLV-I-specific antibodies in whole saliva samples from 10 seronegative and 28 seropositive volunteers from a hospital in southern Japan. Antibodies directed to HTLV-I antigens were found in the salivas from 22 of 28 (79%) of the seropositive subjects. None of the seronegative individuals showed evidence of salivary antibodies. Antibodies directed to the envelope antigens of the virus were found in 21 of 22 positive saliva samples. Secretory antibodies may be important in preventing mucosal transmission.

The zoonotic potential of feline leukemia virus

The many studies that have addressed the possibility for FeLV infection in human beings are reviewed in this article. Because of the many similarities between FeLV-induced immune system impairment in cats and retrovirus related acquired immune deficiency syndrome in man, these two conditions are discussed as well.

Ethnic composition, age and sex, together with location and standard of housing as determinants of HLTV-I infection in an urban Trinidadian community

The presence of antibody to human T-cell leukaemia virus (HLTV-I) has been assessed in 2,143 men and women who represent 83% of all adults aged 35 to 69 years resident in a defined urban community in Trinidad. Individuals of African descent had a higher sero-positivity rate (7.0%) than those originating from India (1.4%), Europe (0%) or of mixed descent (2.7%). Women were infected more frequently than men, and the prevalence of infection increased with age in both sexes. Sero-positivity rates were significantly increased in adults who lived in housing of poor quality (p less than 0.001) or close to water courses (p less than 0.025). These data and others raise the possibility that one route of HLTV-I transmission may be via insect vectors under particular domestic circumstances.