Lymphotrophic Virus Type Research Articles

Clinical importance of extraordinary integration patterns of human T- cell lymphotropic virus type I proviral DNA in adult T-cell leukemia/lymphoma [see comments

The proviral DNA of human T-cell lymphotrophic virus type I (HTLV-I) is known to be integrated monoclonally in the malignant cells of adult T- cell leukemia/lymphoma (ATL), which is a peripheral T-cell malignancy caused by this virus. We studied the relationship between the integration patterns of HTLV-I and clinical characteristics in 89 patients with ATL. The proviral DNA of HTLV-I was examined by the standard Southern blot analysis using the endonucleases EcoRI and Pst I. One clear band of greater than 9 kb was detected in most of the patients (83 case) when cellular DNA was digested with EcoRI. On the other hand, extraordinary integration patterns of HTLV-I proviral DNA were detected in 6 patients; 3 of them showed two bands, while the other 3 showed one band smaller than 9 kb. When cellular DNA was digested with PstI, the band patterns of these patients were quite different from those of typical patients. The patients with the extraordinary integration patterns had clinical characteristics dissimilar to those of the other 83 patients with the ordinary integration pattern. The patients with two bands by EcoRI digestion always had severe hypoxemia with extremely high levels of serum lactate dehydrogenase at first presentation and showed peculiar organ infiltrations, such as retina and muscle, which were less frequent in the other ordinary 83 patients. They all died within 8 months after the onset. In contrast, the patients with one smaller band by EcoRI digestion always had small and mature T lymphocytes with bilobulated nuclei without lymphadenopathy and showed a favorable clinical course, which was uncommon in the ordinary cases. They were alive 20 to 38 months after diagnosis. Rearranged bands of the T-cell receptor gene were detected in all patients with unusual integration. These findings indicate that the integration patterns of HTLV-I proviral DNA have a clinical implication and may be one of the explanations for heterogeneity in the behavior of this disease.

Human T-Cell Lymphotropic Virus Type I—Associated Retinal Lymphoma

Human T-cell lymphotropic virus type I has been associated with a wide range of ocular conditions, including neoplastic, infectious, and inflammatory lesions. We studied a patient infected with human T-cell lymphotrophic virus type I who presented with deep retinal and subretinal infiltrates but without cells in the vitreous. The differential diagnosis included intraocular lymphoma and fungus infection. A chorioretinal biopsy specimen obtained for tissue diagnosis disclosed large atypical mononuclear cells located primarily at the level of the retinal pigment epithelium but focally involving overlying retina. Electron microscopy of this infiltrate showed features consistent with adult T-cell lymphoma/leukemia. Infection by human T-cell lymphotropic virus type I was verified by polymerase chain reaction studies conducted on peripheral-blood mononuclear cells. This case emphasizes the occurrence of intraocular lesions in adult T-cell lymphoma/leukemia that clinically show some features similar to those of the usual ocular lymphoma (reticulum cell sarcoma); diagnosis can be established by chorioretinal biopsy, thereby allowing appropriate therapy.

Human T cell lymphotropic virus type 1 in Zimbabwe

Human T cell lymphotrophic virus type 1 (HTLV-1) causes myelopathy and adult T cell leukaemia. Knowledge of its distribution in Africa is limited. We performed HTLV-1 testing by enzyme immunoassay, with immunofluorescence assay confirmation, on 931 blood donors, 88 human immunodeficiency virus (HIV) seronegative patients with clinical features of acquired immune deficiency syndrome, 23 multi-transfused haemophiliacs, 8 patients with haematological malignancies, and 32 patients with neurological disease. One blood donor and 3 neurological patients, all 3 with spinal cord syndromes, were HTLV-1-seropositive. Two of the 3 HTLV-1-positive myelopathy patients were co-infected with HIV and both experienced unusually rapid progression of neurological disease. HTLV-1 is uncommon but can be associated with myelopathy in Zimbabwe.

False-Positive Serologic Tests for Human T-Cell Lymphotropic Virus Type I Among Blood Donors Following Influenza Vaccination, 1992

From October 31 through December 15, 1991, 10 blood donors to the American Red Cross Blood Services, Badger Region (ARCBS), were found to have false-positive screening enzyme-linked immunosorbent assays (ELISAs) for antibodies to two or more of the following viruses: human immunodeficiency virus type 1 (HIV-1), human T-cell lymphotrophic virus type 1 (HTLV-I), and hepatitis C virus (HCV). An investigation by the Division of Health, Wisconsin Department of Health and Social Services (WDOH), and the ARCBS indicated that the risk for false-positive reactivity was associated with antecedent receipt of influenza vaccine formulated for the 1991-92 season. In March 1992, the ARCBS began use of newly available ELISAs for anti-HIV (HIVAB, HIV-1/HIV-2 (rDNA) EIA [Abbott Laboratories, Abbott Park, Illinois]) and anti-HCV (HCV 2.0 ELISA [Ortho Diagnostic Systems, Raritan, New Jersey]), while continuing to test with the ELISA for anti-HTLV-I [HTLV-I ELISA (Abbott Laboratories) used in 1991. From January 1 through October 13, 1992, the ARCBS identified 19 blood donors with repeatedly reactive ELISAs for HTLV-I. However, from October 14 through November 10, 15 false-positive ELISAs for HTLV-I were reported by the ARCBS to the WDOH. As a result of this increase, the ARCBS conducted a case-control study to assess the relation between influenza vaccination and testing positive for HTLV-I. This report summarizes the results of the study.

Double-negative (CD4- CD8-) T cells from adult T-cell leukemia patients also have poor expression of the T-cell receptor alpha beta/CD3 complex

We present four patients with adult T-cell leukemia (ATL) derived from a novel T-cell subset (CD4-, CD8- [double-negative, DN], T-cell receptor [TCR] alpha beta+). In the ATL cells of these patients, neither gene nor surface expression of CD4 and CD8 antigens was detected. Clinical and laboratory data showed no difference between DN-ATL and CD4+ATL patients. In contrast to typical CD4+ATL cells, DN-ATL cells were shown to express the protein and messenger RNA (mRNA) for S100 beta in immunocytochemical assay and the reverse-transcription polymerase chain reaction assay. The mean fluorescence intensity of the TCR/CD3 complex was extremely low in all four DN-ATL patients as well as in typical CD4+ ATL. All four patients had TCR beta and gamma chain gene rearrangements, with deletion of TCR delta chain gene and mRNA expression for TCR alpha, beta, and CD3 delta but not for TCR gamma and delta chain genes. Thus, CD4- CD8- TCR alpha beta T cells are also a target for human T-cell lymphotrophic virus type I-induced leukemogenesis. In addition, expression of the TCR alpha beta/CD3 complex on the DN-ATL cells was further diminished by the addition of anti-CD3 or anti-TCR alpha beta monoclonal antibody. These results suggest that the decreased expression of the TCR alpha beta/CD3 complex by ATL cells plays a key role in the development of ATL, irrespective of CD4 expression.

Double-Negative (CD4– CD8–) T Cells From Adult T-Cell Leukemia Patients Also Have Poor Expression of the T-Cell Receptor αβ/CO3 Complex

Abstract We present four patients with adult T-cell leukemia (ATL) derived from a novel T-cell subset (CD4-, CD8- [double-negative, DN], T-cell receptor [TCR] alpha beta+). In the ATL cells of these patients, neither gene nor surface expression of CD4 and CD8 antigens was detected. Clinical and laboratory data showed no difference between DN- ATL and CD4+ATL patients. In contrast to typical CD4+ATL cells, DN-ATL cells were shown to express the protein and messenger RNA (mRNA) for S100 beta in immunocytochemical assay and the reverse-transcription polymerase chain reaction assay. The mean fluorescence intensity of the TCR/CD3 complex was extremely low in all four DN-ATL patients as well as in typical CD4+ ATL. All four patients had TCR beta and gamma chain gene rearrangements, with deletion of TCR delta chain gene and mRNA expression for TCR alpha, beta, and CD3 delta but not for TCR gamma and delta chain genes. Thus, CD4- CD8- TCR alpha beta T cells are also a target for human T-cell lymphotrophic virus type I-induced leukemogenesis. In addition, expression of the TCR alpha beta/CD3 complex on the DN-ATL cells was further diminished by the addition of anti-CD3 or anti-TCR alpha beta monoclonal antibody. These results suggest that the decreased expression of the TCR alpha beta/CD3 complex by ATL cells plays a key role in the development of ATL, irrespective of CD4 expression.

Two color flow cytometric analysis of lymphocytes in HTLV-I carrier children.

Phenotypic changes in lymphocytes from healthy children with antibody for human T lymphotrophic virus type I (HTLV-I) were studied using two color flow cytometry. The subjects were high school students within a small district of Kyushu, Japan. In the carrier group, a subset of lymphocytes which expressed CD8+CD57+ was significantly lower in percentage (P < 0.01) and in number (P < 0.05). There was no significant difference between carriers and non-carriers in the percentage and number of CD4+Leu8+ cells or CD4+HLA-DR+ cells. The IgG levels were slightly higher in carriers than in non-carriers (P < 0.05). These findings suggest that HTLV-I-infected cells may affect the immune system in healthy carrier children.

Differentiation of a medulloblastoma cell line towards an astrocytic lineage using the human T lymphotropic retrovirus-1

Constituent cells of medulloblastoma, the most common brain tumor occurring in childhood, resemble the primitive neuroepithelial cells normally found in the developing nervous system. However, mutational events prevent their further differentiation. We used the human T cell lymphotrophic virus type 1 to activate these deregulated immature cells by means of its transactivating protein Tax. Concomitant with viral infection was a decrease in cell proliferation characterized by inhibition of [ 3H]thymidine incorporation and in the number of cells in the G2/M phase of the cell cycle. Morphological changes suggested that medulloblastoma cells differentiated along the astrocytic lineage. The glial phenotype was confirmed by the induction of the glial fibrillary acidic protein and the glial enzyme glutamine synthetase. A direct viral effect and/or secondary effects to viral infection via paracrine/autocrine pathways could counterbalance the maturational defect in these medulloblastoma cells.

Multiple False-positive Serologic Tests for HIV, HTLV-1, and Hepatitis C Following Influenza Vaccination, 1991

(1) To assess factors associated with the occurrence of multiple false-positive viral enzyme-linked immunosorbent assays (ELISAs) for human immunodeficiency virus (HIV), human T-cell lymphotrophic virus type 1 (HTLV-1), and hepatitis C virus (HCV) among individual blood donors and (2) to determine the frequency and time course of this phenomenon. Case-control study. A regional blood center. Blood donors found to have multiple false-positive viral ELISAs (case donors) and randomly selected seronegative controls (control donors) who donated between October 31, 1991, and December 15, 1991. An additional random sample of 262 donation records was reviewed to calculate the proportion of donors who received influenza vaccine. Multiple false-positive viral ELISAs, receipt of influenza vaccination formulated for the 1991-1992 influenza season, and follow-up ELISA results on serum samples obtained from case donors. Among 17,941 donors, 10 case donors were identified. Nine of the 10 case donors received influenza vaccine, compared with three of 30 control donors (odds ratio [OR] = 81; 95% confidence interval [CI], 6 to 3670; P less than .001). Among nine case donors, the mean time between vaccination and blood donation was 26 days (range, 9 to 68 days). Follow-up ELISAs of serum samples from seven case donors obtained 52 to 130 days (mean, 75 days) after vaccination demonstrated reversion to HIV and HTLV-1 seronegativity in all but one specimen, with persistence of positive HCV ELISAs in four specimens. We estimate between 0.6% and 1.7% of blood donors who received influenza vaccine this season had multiple false-positive viral ELISAs. The occurrence of multiple false-positive viral ELISAs among blood donors was associated with influenza vaccination, but was infrequent among vaccinees. This phenomenon is of short duration for HIV and HTLV-1, but may persist longer for HCV. We recommend influenza vaccinees not be deferred from blood donation. Blood donors with multiple false-positive viral ELISAs should be considered for future reentry as blood donors.

As the Blood Supply Gets Safer, Experts Still Call for Ways to Reduce the Need for Transfusions

IN COMPLIANCE with the Food and Drug Administration's recommendation, all blood banks in the United States on June 1 began testing donated blood for the human immunodeficiency virus type 2 (HIV-2), a rare strain of the virus that causes acquired immunodeficiency syndrome. This latest requirement has lengthened the gauntlet of tests donated blood must be run through before it can be used in transfusions. According to the American Association of Blood Banks, eight screening tests are now used, including tests for the syphilis spirochete (<i>Treponema pallidum</i>), HIV-1, HIV-2, human T-cell lymphotrophic virus type 1, hepatitis B virus, hepatitis C virus, and two surrogate tests for non-A, non-B hepatitis viruses. Prior to 1985, blood was screened only for<i>T pallidum</i>and hepatitis B virus (Dane particle). <h3>Not Without Hazards</h3> Indisputably, blood transfusions save the lives of many thousands of patients each year. Nevertheless, there is a growing recognition of the health

HTLV-I DNA Sequences in CNS Tissue of a Patient with Tropical Spastic Paraparesis and HTLV-I-Associated Myelopathy

Human T cell lymphotrophic virus type I (HTLV-I) is the etiologic agent of adult T cell lymphoma/leukemia (ATLL) and tropical spastic paraparesis/HTLV-I-associated myelopathy (TSP/HAM). We studied an HTLV-I-seropositive, white man diagnosed in 1977 with ATLL and 10 years later, 6 months prior to his death, with TSP/HAM. Sections of brain, spinal cord, and visceral tissues were examined histologically, immunohistochemically, by in situ hybridization, and by the polymerase chain reaction (PCR). PCR amplification of a region of the polymerase (pol) gene of HTLV-I from visceral tissue demonstrated the presence of proviral HTLV-I DNA in paraffin-embedded sections from the liver and in DNA extracted from frozen sections of kidney and spleen, but failed to demonstrate viral sequences in paraffin sections of the lung and a lymph node. PCR analysis of CNS tissue demonstrated viral sequences in regions of the brain including frozen samples from cerebellum and cerebral cortex and paraffin sections of the thoracic spinal cord, but failed to detect proviral DNA in sections from a region in the lumbar cord. These results map the distribution of HTLV-I DNA sequences in the CNS of a patient with TSP/HAM for 3 months.

Characterization of HTLV-I in vivo infected T cell clones. IL-2-independent growth of nontransformed T cells.

Mononuclear cells from subjects infected with human T lymphotrophic virus type I (HTLV-I) display a unique ability to proliferate in vitro in the absence of mitogens or exogenous growth factors. Subjects who have developed an HTLV-I-associated myelopathy (HAM) show an even higher degree of spontaneous proliferation concomitant with transcription of the HTLV-I provirus. The mechanism underlying HTLV-I-induced T cell activation was investigated by characterizing a series of HTLV-I-infected T cell clones generated from the blood of subjects with HAM. Approximately 15% of the T cell clones generated were HTLV-I infected as determined by polymerase chain reaction and Southern blotting. Infected T cell clones displayed altered growth kinetics as they continued to incorporate tritiated thymidine 7 to 14 days after stimulation, a time when noninfected T cell clones had returned to a resting state. This was not due to transformation as all the T cell clones required periodic restimulation with mitogens and feeder cells for continued growth. Although HTLV-I-infected T cell clones showed increased expression of the IL-2 receptor p55 chain, the spontaneous clonal proliferation was not inhibited by anti-IL-2 receptor mAb. Moreover, the spontaneous clonal proliferation was insensitive to cyclosporin A and FK 506 while being highly sensitive to rapamycin, which is known to inhibit IL-2-mediated signaling. Together these results demonstrate that IL-2 is not required for the HTLV-I-induced spontaneous clonal proliferation and further suggest that HTLV-I may induce signaling pathways replacing an IL-2 receptor signal proximal to the site of action of rapamycin.

Characterization of a novel T-cell lymphoma cell line established from a patient with systemic lupus erythematosus-associated lymphoma

A malignant lymphoma developed in a 46-year-old male patient who had had systemic lupus erythematosus (SLE) for 18 years. The lymphoma was at disease stage IV at initial examination, and the patient died shortly thereafter. The lymphoma cells were cultured in vitro, and a continous cell line, named SMZ-1, was established. The SMZ-1 cells, as well as the parental lymphoma cells, were of helper/inducer T-cell immunophenotype; they were positive for CD2, CD3, and CD4 antigens, and negative for CD8. Expression of CD5 and CD7 antigens was observed in a small percentage of the cells. The activation markers identified by antibodies against CD25, CD71, and HLA-DR antigens were positive. Cytogenetic analysis revealed that the SMZ-1 cells had a characteristic translocation between chromosomes 6 and 14 [t(6;14)(p21.1;q24)]. Southern blot analysis of DNA extracted from the cells demonstrated clonal rearrangement of the T cell receptor β-chain gene. Integration of the human T-cell lymphotrophic virus type I (HTLV-I) genome was negative. The SMZ-1 cell line should thus provide a useful model for characterization of peripheral T-cell lymphomas.

Cells surviving infection by human immunodeficiency virus type 1: vif or vpu mutants produce non-infectious or markedly less cytopathic viruses

Under conditions in which a clonal cell line (M10) isolated from a human T cell lymphotrophic virus type I-transformed MT-4 cell line was completely killed by infection with wild-type human immunodeficiency virus type 1 (HIV-1), equivalent M10 cells survived infection with HIV-1 vif, vpr or vpu mutant virus after transient cytopathic effects. Several cell clones, which were isolated from the proliferating M10 cells after infection with vif and vpu mutant viruses (M10/vif- and M10/vpu-), had heterogeneous HIV-1 phenotypes in terms of HIV-1 antigen expression, their syncytium forming capacity, reverse transcriptase activity and the infectivity of HIV-1 particles produced. When the replication kinetics of the HIV-1 particles produced were assayed in M10 cells, the clones could be classified into three types, i.e. type I producing non-infectious HIV-1, type II producing infectious HIV-1 with low replicative ability and type III producing infectious HIV-1 with a replicative ability similar to that of wild-type HIV-1. HIV-1 major viral cell proteins and virus particle fractions were almost typical in types II and III but not in type I. Electron microscopic examination of particles released by I, II and III clones revealed rare defective, predominantly defective and essentially normal virions, respectively. Northern and Southern blot analyses revealed no apparent deletion in the proviral DNA and mRNA prepared from these clones, except in the case of type I and II clones isolated from M10/vpu- which contained large deletions in the mRNAs for gag and gag-pol proteins. Thus, M10 cells surviving infection with HIV-1 vif or vpu mutants are heterogeneous, persistently expressing HIV-1 antigens and producing non-infectious or less cytopathic virus.

Interaction of the human T-cell lymphotrophic virus type I (HTLV-I) transcriptional activator Tax with cellular factors that bind specifically to the 21-base-pair repeats in the HTLV-I enhancer.

The human T-cell lymphotrophic virus type I (HTLV-I) Tax protein activates transcription from three 21-base-pair (bp) repeat sequences in the viral enhancer. Using gel electrophoretic mobility-shift assays, we now show that Tax interacts directly with the nuclear proteins, Tax activation factors (TAFs), that bind the 21-bp repeats. This interaction is demonstrated by decreased electrophoretic mobilities of the TAFs-21-bp-repeats complexes upon supply of Tax exogenously. Formation of the TAFs-21-bp-repeats and Tax-TAFs-21-bp-repeats complexes correlates with in vivo transactivation by Tax. Furthermore, interaction of Tax with TAFs enhances their binding to the 21-bp repeats. These data indicate that trans-activation by Tax is most likely mediated by interaction of Tax with TAFs.

HTLV-1 Antibody Testing in a Saudi Arabian Blood Donor Population

Human-T lymphotrophic virus Type 1 may be transmitted by cellular blood products. A low but definite risk exists that recipients of HTLV-1 infected products may develop severe even fatal disease. After one year of screening for HTLV-1 antibodies in 12,851 units of blood collected from a multinational volunteer donor population of which 42.6% were Saudi nationals, we found two units of blood which reacted repeatedly positive in the screen test. In both cases, the Western Blot confirmatory test was indeterminate in that not all bands required for a positive reaction were present. Both donors were expatriates from North America either living in an endemic area or with Caribbean ancestors. Although more than 5,000 Saudi national donors were tested and found negative for HTLV-1 antibodies, a statistical estimate of the maximal risk of finding a positive donor in this donor population subgroup is in the order of 0.055%. Based on these results it is recommended that blood banks in this region screen for HTLV-1.

Post-mortem diagnosis of human T lymphotrophic virus type-1 (HTLV-1) associated myelopathy by detection of HTLV-1 DNA in the spinal cord of a patient with post-transfusional myelopathy

Human T lymphotrophic virus type-1(HTLV-1) is thought to be an etiological agent of HTLV-1 associated myelopathy (HAM). Therefore, a definitive diagnosis of HAM can not be made if information on the presence of antibody against HTLV-1 is not available, even though clinical and histopathological features strongly indicate the disease. In this study, HTLV-1 DNA was detected in the formalin-fixed, paraffin-embedded spinal cord of an autopsy case with post-transfusional myelopathy using the polymerase chain reaction (PCR). Ante-mortem HAM was not suspected of and the antibody has not been examined. Neuropathological examination of the sequential sections revealed a loss of axons and myelin sheaths in the white matter, resembling the histopathology of HAM. The post-mortem detection of HTLV-1 DNA by PCR may be useful for the confirmation of HAM in cases which were not provided with appropriate clinical data.

Direct Binding of Complement Component C1q to Human Immunodeficiency Virus (HIV) and Human T Lymphotrophic Virus-I (HTLV-I) Coinfected Cells

Previous studies have shown that coinfection of the human T lymphotrophic virus type I (HTLV-I) chronically infected cell line MT4 with human immunodeficiency virus type 1 (HIV-1) results in cells which spontaneously activate complement via the classical pathway. This complement activation was antibody independent, yet required C2, suggesting either direct C1, C4, or C2 activation. Because some animal retroviruses have been shown to bind human C1q directly, the present study investigated the possible direct binding of C1q by HIV coinfected MT4 cells. Coinfected cells bound both C1q present in serum and highly purified C1q. Binding of C1q resulted in formation of active C1 on the cell surface, which could in turn activate complement as shown by C4 consumption. The C1q binding was not HIV-isolate specific since infection of MT4 cells with any of three diverse isolates all induced C1q binding. Purified collagen-like region (CLR) and globular region (GR) fragments of C1q both bound to coinfected cells, suggesting a mechanism of binding by C1q similar to that of fibronectin-C1q binding. However, culture of coinfected cells in serum-free (fibronectin-free) medium did not reduce C1q binding. A second HTLV-I chronically infected line, SLB-1, also displayed increased binding of C1q after HIV infection. The H9 cell line, which is not HTLV-I infected, did not bind C1q after HIV infection. These results suggest that a retrovirus protein expressed by coinfected cells directly binds C1q resulting in classical complement activation. This type of activation may have profound biological effects in persons coinfected with HIV-1 and HTLV-I.

Lymph nodes in incipient adult T-cell leukemia-lymphoma with Hodgkin's disease-like histologic features

Lymph nodes were examined from four patients with incipient adult T-cell leukemia-lymphoma (ATLL) who had mild lymphadenopathy, fatigue, no or a few atypical lymphocytes in their peripheral blood, and integrated proviral human T-cell lymphotrophic virus type I (HTLV-I) DNA in the nodes. The HTLV-I DNA was detected by southern blot analysis and/or polymerase chain reaction in the lymph nodes of all cases. The nodal architecture was preserved. Some scattered or aggregated highly lobular, cerebriform, or Reed-Sternberg-like giant cells were observed, with occasional mitoses and diffuse infiltration of small to medium-sized lymphocytes, with no or minimal nuclear abnormalities in the enlarged paracortex. The giant cells were usually positive for Ki-1 and also for UCHL-1 and other T-cell markers but negative for Ber-H2. Rearrangement and/or deletion of T-cell receptors were found in three of four patients. All patients died within 2 years, with transformation to overt leukemia-lymphoma occurring in three patients, and pulmonary carcinoma in one. The incipient or prelymphomatous phase of ATLL should be differentiated from Hodgkin's disease because of the distinctly different prognoses of these two diseases.

The epidemiology of the human T‐cell lymphotrophic virus type I and type II: etiologic role in human disease

The epidemiology of the human T‐cell lymphotrophic virus type I and type II: etiologic role in human disease