[Prelymphoma as a stage of malignant lymphoma (baboon malignant lymphoma model)]

Ten percent of the monkeys (more then 400 animals) from P. hamadrias herd of Sukhumi monkey colony died of a 20 year-long enzootic of malignant lymphoma associated with STLV-1 retrovirus. Retrospective analysis revealed regular (in more than 80% of cases) development of prelymphoma preceded by malignant process for a considerable time (up to 10 years or more). Prelymphoma occurred as mild hemopoietic inhibition including lymphopoiesis. Clinico-morphological signs of prelymphoma were: hypoplasia, edema and discomplexation in lymph nodes, anemia and inflammatory, i. e. degenerative lesions of the skin and mucous membranes.

Skeletal muscle involvement in human immunodeficiency virus (HIV)-infected patients in the era of highly active antiretroviral therapy (HAART)

Skeletal muscle involvement can occur at all stages of human immunodeficiency virus (HIV) infection, and may represent the first manifestation of the disease. Myopathies in HIV-infected patients are classified as follows: (1) HIV-associated myopathies and related conditions, including HIV polymyositis, inclusion-body myositis, nemaline myopathy, diffuse infiltrative lymphocytosis syndrome (DILS), HIV-wasting syndrome, vasculitic processes, myasthenic syndromes, and chronic fatigue; (2) muscle complications of antiretroviral therapy, including zidovudine and toxic mitochondrial myopathies related to other nucleoside-analogue reverse-transcriptase inhibitors (NRTIs), HIV-associated lipodystrophy syndrome, and immune restoration syndrome related to highly active antiretroviral therapy (HAART); (3) opportunistic infections and tumor infiltrations of skeletal muscle; and (4) rhabdomyolysis. Introduction of HAART has dramatically modified the natural history of HIV disease by controlling viral replication, but, in turn, lengthening of the survival of HIV-infected individuals has been associated with an increasing prevalence of iatrogenic conditions.

High simian T-cell leukemia virus type 1 proviral loads combined with genetic stability as a result of cell-associated provirus replication in naturally infected, asymptomatic monkeys

Simian T-cell leukemia virus type 1 (STLV-1) is a primate T cell leukemia virus of the group of oncogenic delta retroviruses. Sharing a high level of genetic homology with human T cell leukemia virus type 1 (HTLV-1), it is etiologically linked to the development of simian T cell malignancies that closely resemble HTLV-1 associated leukemias and lymphomas and might thus constitute an interesting model of study. The precise nature of STLV-1 replication in vivo remains unknown. The STLV-1 circulating proviral load of 14 naturally infected Celebes macaques (Macaca tonkeana) was measured by real-time quantitative PCR. The mean proportion of infected peripheral mononuclear cells was 7.9%, ranging from <0.4% to 38.9%. Values and distributions were closely reminiscent of those observed in symptomatic and asymptomatic HTLV-1 infected humans. Sequencing more than 32 kb of LTRs deriving from 2 animals with high proviral load showed an extremely low STLV-1 genetic variability (0.113%). This paradoxical combination of elevated proviral load and remarkable genetic stability was finally explained by the demonstration of a cell-associated dissemination of the virus in vivo. Inverse PCR (IPCR) amplification of STLV-1 integration sites evidenced clones of infected cells in all infected animals. The pattern of STLV-1 replication in these asymptomatic monkeys was indistinguishable from that of HTLV-1 in asymptomatic carriers or in patients with inflammatory diseases. We conclude that, as HTLV-1, STLV-1 mainly replicates by the clonal expansion of infected cells; accordingly, STLV-1 natural monkey infection constitutes an appropriate and promising model for the study of HTLV-1 associated leukemogenesis in vivo.

Acute human T-lymphotropic virus type 1-associated myelopathy: a clinicopathologic study

BACKGROUND

Recently, acute human T-lymphotropic virus type 1-associated myelopathy (HAM) was reported clinically without pathologic information. We report an autopsy case of acute HAM.

OBJECTIVE

To report the case of a 52-year-old man with acute-onset gait disturbance followed by rapidly progressive paraplegia, who died 9 months later.

RESULTS

The postmortem study showed swelling of the thoracic spinal cord. Histologically, there was inflammation and vacuolation in the white matter.

CONCLUSION

We propose that these pathologic findings, mimicking tropical spastic paraparesis, may represent the characteristic pathologic features of acute HAM.

Axonal damage: a key predictor of outcome in human CNS diseases

Axonal damage has recently been recognized to be a key predictor of outcome in a number of diverse human CNS diseases, including head and spinal cord trauma, metabolic encephalopathies, multiple sclerosis and other white-matter diseases (acute haemorrhagic leucoencephalitis, leucodystrophies and central pontine myelinolysis), infections [malaria, acquired immunodeficiency syndrome (AIDS) and infection with human lymphotropic virus type 1 (HTLV-I) causing HTLV-I-associated myelopathy (HAM)/tropical spastic paraparesis (TSP)] and subcortical ischaemic damage. The evidence for axonal damage and, where available, its correlation with neurological outcome in each of these conditions is reviewed. We consider the possible pathogenetic mechanisms involved and how increasing understanding of these may lead to more effective therapeutic or preventive interventions.

Association of primate T-cell lymphotropic virus infection of pig-tailed macaques with high mortality

Natural infection of humans with human T-cell lymphotropic virus type I (HTLV-I) and of old world nonhuman primates with the simian counterpart, STLV-I, is associated with development of neoplastic disease in a small percentage of individuals after long latent periods. HTLV-I is also the etiologic agent of a more rapidly progressive neurologic disease, HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP). Macaques have been used experimentally in studies to evaluate HTLV-I candidate vaccines for efficacy, but no evidence of disease was observed. Here we report experimental infection of pig-tailed macaques with STLV-I(sm) and HTLV-I(ACH), both of which were associated with a disease syndrome characterized by rapid onset, hypothermia, lethargy, and death within hours to days. Other pathologic sequelae included diarrhea, rash, bladder dysfunction, weight loss, and, in one animal, arthropathy. Both retroviruses were detected in the central nervous systems of some animals, either by culture or by direct antigen capture for p19 Gag in cerebrospinal fluid. Although virus was recovered throughout infection from peripheral blood mononuclear cells (PBMC), all infected macaques maintained low antiviral antibody titers and stable proviral burdens, which generally ranged between 10 and 100 copies per 10(6) PBMC. However, of 13 macaques infected with HTLV-I(ACH) or STLV-I(sm), seven animals (54%) died between 35 weeks and 412 years after infection. This unexpected high mortality within a relatively short time suggests that infection of pig-tailed macaques might be a useful model for studying immune responses to and pathologic events resulting from HTLV-I infection.

Oncogenic retroviruses in animals and humans

Retrovirology emerged as a branch of science at the beginning of the last century. However, a deeper insight into the pathology of retroviruses and retrovirus-induced cancers could only be gained after the advent of modern biochemical and molecular biological techniques in the 1970s and 1980s. This study gives an overview of the known and well-characterised exogenous oncogenic animal retroviruses and the only human oncoretrovirus discovered thus far, HTLV-1. It briefly reviews retrovirus genetics, mechanisms of oncogenic transformation and malignant diseases caused by retroviruses.

Spinocerebellar syndrome in patients infected with human T-lymphotropic virus types I and II (HTLV-I/HTLV-II): report of 3 cases from Panama

Cerebellar symptoms at onset are unusual in HTLV-I/II-associated tropical spastic paraparesis (TSP). A prospective study of neurological disorders in Panama (1985-1990) revealed 13 patients with TSP and 3 with HTLV-I/II-associated spinocerebellar syndrome (HSCS) presenting at onset loss of balance, wide-based stance and gait, truncal instability, and mild leg ataxia (vermian cerebellar syndrome), with absent upper limb dysmetria but with postural tremor, downbeat nystagmus, and dysarthria. In 4-5 years, spinal cord manifestations of TSP developed, including spastic paraparesis, pyramidal signs, bladder and sphincter disturbances. Two patients were infected with HTLV-I and another one, a Guaymi Amerindian woman, with HTLV-II. Magnetic resonance imaging (MRI) demonstrated cerebellar atrophy involving predominantly the superior vermis. Mild axonal peripheral neuropathy in the lower limbs, dorsal column involvement and inflammatory myopathy were found by neurophysiology studies. There are 14 similar cases reported in Japan and Canada, but to our knowledge these are the first documented cases of HSCS in the tropics. A cerebellar syndrome constitutes another form of presentation of HTLV-I/II infection of the nervous system.

Adult T cell leukemia/lymphoma with lymphopenia in a Korean

We experienced a case of adult T cell leukemia/lymphoma (ATLL) in a 48-year-old Korean female, who has never been abroad since birth and no history of blood transfusion. The patient had hypercalcemia and multiple lymphadenopathy. Histopathologic study of left cervical lymph node (LN) and bone marrow (BM) revealed that infiltrates of malignant lymphoid cells were composed of small, medium and large cells with pleomorphic nuclei. Smears of peripheral blood (PB) showed lymphopenia (16%) with the appearance of a few atypical lymphoid cells (less than 2%), but not the typical clover leaf cells seen in ATLL. Immunophenotypic study of LN and BM revealed T cell phenotype. PB showed increased CD4+ T cell (T(H), CD3/CD4+, 57%) and decreased CD8+ T cell counts (T(S), CD3/CD8+, 6.7%). The sera of the patient and her family were reactive for HTLV-I antibody. The specific sequences of pol, env, and tax of HTLV-I DNA were detected in the lymphoma cells and peripheral blood mononuclear cells (PBMC) using polymerase chain reaction. Ultrastructural examination of PBMC confirmed numerous type c virus particles in extracellular space. This case was an acute type of ATLL without overt leukemic features in PB. Despite chemotherapy and intensive conservative treatment, she died 3 months after admission.

T-cell lymphoma in a savanna monkey (Cercopithecus aethiops) probably related to simian T-cell leukemia virus infection

Lymphoma was seen in an 11-year-old female savanna monkey (Ceropithecus aethiops). The superficial inguinal and visceral lymph nodes were markedly enlarged, and their architecture was completely effaced by neoplastic cells. The neoplastic cells, which were highly pleomorphic, resembled those in adult T-cell lymphoma-leukemia in humans. Ultrastructurally the neoplastic cells were characterized by nuclear irregularity and clustered dense bodies, and almost all cells showed positivity for CD3. The animal had been reared with her family, and her mother and 2 brothers had antibodies reactive to human T-cell leukemia virus. This virus serologically cross-reacts with simian T-cell leukemia virus, which may be the causative agent of the present neoplasm.

Perivascular T cells are infected with HTLV-I in the spinal cord lesions with HTLV-I-associated myelopathy/tropical spastic paraparesis: double staining of immunohistochemistry and polymerase chain reaction in situ hybridization

HTLV-I-infected cells play an important role in pathogenesis HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP). Our previous studies of quantitative polymerase chain reaction (PCR) and in situ PCR suggested that T cells infiltrating in the spinal cord lesion were infected with HTLV-I. To elucidate the localization of HTLV-I proviral DNA directly, we performed double staining using immunohistochemistry and PCR in situ hybridization (PCR-ISH). Fresh frozen sections of the spinal cord from four HAM patients taken at autopsy were first immunostained with antibodies to pan T cells (UCHL-1), macrophages (KP-1) and helper/inducer T cells (OPD4). Then PCR-ISH was carried out with specific primers and probe for the HTLV-I pX region. UCHL-1-positive cells were noted around perivascular areas and, to some extent, in the parenchyma. Of the UCHL-1-positive cells, 9.4% (case 1), 9.6% (case 2), 1.1% (case 3) and 6.7% (case 4) became positive in HTLV-I PCR-ISH. UCHL-1-negative cells were HTLV-I PCR-ISH negative and almost all KP-1-positive cells were HTLV-I negative. HTLV-I was localized to OPD4-positive cells in examined lesions of cases 2 and 4. These data are a direct demonstration of HTLV-I proviral DNA localizing to infiltrated T cells in HAM/TSP spinal cord lesions.

Thiol compounds rescue growth inhibition by retinoic acid on HTLV-I (+) T lymphocytes; possible mechanism of retinoic-acid-induced growth inhibition of adult T-cell leukemia cells

We demonstrated significant growth inhibition by retinoic acid (RA) of HTLV-I (+) T-cell lines (ATL-2 and HUT102), but not HTLV-I (-) T-cell lines (MOLT-4 and Jurkat). We hypothesized that the mechanism of growth inhibition by RA depends on an imbalance in redox potential. To examine the effect of exogenous thiol compounds for the growth of HTLV-I (+) T-cell lines by RA, HTLV-I (+) T-cell lines were cultured with several thiol compounds (thioredoxin, L-cystine, and GSH), following addition of 13-cis RA or ATRA, respectively, in cultured with thiol free medium. Unexpectedly, thiol compounds alone did not restore growth inhibition of HTLV-I (+) T-cell lines. However, when those cells were preincubated with thiol compounds for 24 hours, no growth inhibition by 13-cis RA or ATRA was observed. These results suggest that thiol compounds are associated strongly with sensitivity to RA of HTLV-I (+) T cells, but not of HTLV-I (-) T cells and that thiol compounds serve an important role on HTLV-I (+) T cells.

Bovine leukemia virus-induced clinical signs and morphological changes of encephalitozoonosis in rabbits

Fourteen three-month-old rabbits spontaneously-infected with the microsporidium Encephalitozoon cuniculi Levaditi, Nicolau et Schoen, 1923 were inoculated intravenously with lymphocytes (Ly) from seropositive bovine leukemia virus infected cattle (Ly/BLV) or with fetal lamb kidney cells infected with bovine fetal leukemia (FLK/BLV). Thirteen rabbits were seropositive to BLV at least for a period of three months. Six rabbits died of pulmonary lesions. Chronic inflammatory lesions of encephalitozoonosis were found in six rabbits killed between 454 and 548 days of the observation period. Five animals bore subcutaneous granulomas. Immunohistochemically, E. cuniculi was demonstrated in the inflammatory lesions of rabbits studied. Control animals also spontaneously infected with E. cuniculi did not show clinical signs of encephalitozoonosis. Morphological changes were found incidentally in the form of small glial foci and focal interstitial nephritis in these animals. The combined action of BLV-E. cuniculi on the bodies of rabbits is proposed as a suitable model for the study of encephalitozoonosis in man with human immunodeficiency virus (HIV) infection.

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.

Interspecies transmission of macaque simian T-cell leukemia/lymphoma virus type 1 in baboons resulted in an outbreak of malignant lymphoma

An outbreak of malignant lymphoma has been observed in one of the baboon (Papio hamadryas) stocks of Sukhumi Primate Center. More than 300 cases in this "high-lymphoma stock" have been registered since 1967. Human T-cell lymphotropic virus type 1 (HTLV-1)-related virus was implicated as the etiologic agent of Sukhumi baboon lymphoma. The origin of this virus remained unclear. Two possibilities were originally considered: the origin could be baboon simian T-cell leukemia/lymphoma virus type 1 (STLV-1) or HTLV-1 (before the outbreak started, some Sukhumi baboons were inoculated with human leukemic material). The third possibility entered recently: interspecies transmission of rhesus macaque STLV-1 to baboons. It was prompted by the finding of very close similarity between STLV-1 991-1cc (the strain isolated from a non-Sukhumi baboon inoculated with material from a Sukhumi lymphomatous baboon) and rhesus STLV-1. To test this hypothesis, we investigated 37 Sukhumi STLV-1 isolates from baboons of high-lymphoma stock by PCR discriminating rhesus type and baboon type STLV-1 isolates. All of them were proved to be rhesus type STLV-1. In contrast, all six STLV-1 isolates from baboons belonging to other stocks or populations were of baboon type. The PCR results were fully confirmed by DNA sequence data. The partial env gene gene sequences of all four STLV-1 isolates from Sukhumi lymphomatous baboons were 97 to 100% similar to the sequence of known rhesus STLV-1 and only 85% homologous with the sequence of conventional baboon STLV-1. Thus, interspecies transmission of STLV-1 from rhesus macaques (or closely related species) to baboons occurred at Sukhumi Primate Center. Most probably this event initiated the outbreak of lymphoma in Sukhumi baboons.

Interleukin-2 increases production and secretion of parathyroid hormone-related peptide by human T cell leukemia virus type I-infected T cells: possible role in hypercalcemia associated with adult T cell leukemia

Although parathyroid hormone-related peptide (PTHRP) is produced by adult T cell leukemia (ATL) cells and causes hypercalcemia in ATL patients, very little is known about the regulation of PTHRP gene expression in the leukemic cells. The present study was undertaken to clarify the role of T cell growth factor, interleukin-2 (IL-2), in the expression of PTHRP gene, using a human T cell leukemia virus type I (HTLV-I)-infected T cell line, MT-2. Recombinant human IL-2 caused a transient increase in the steady state level of PTHRP messenger RNA (mRNA) in MT-2 cells, and a maximal effect was observed at 3-6 h. The effect of IL-2 was dose dependent, with a maximal response being observed at 10(-10) M. A monoclonal antibody against IL-2 receptor (anti-Tac antibody) inhibited the IL-2-induced increase in PTHRP mRNA level. Recombinant human IL-1, IL-3, IL-4, and IL-6 failed to increase PTHRP mRNA level. Nuclear run-off transcription assay showed that the transcription rate of the PTHRP gene was modestly increased by IL-2. In addition, IL-2 caused a substantial increase in the stability of PTHRP mRNA, compared with control cells in which the apparent half-life of PTHRP mRNA was less than 30 min after RNA synthesis was inhibited by the RNA polymerase II inhibitor, dichlorobenzimidazole riboside. The secretion of PTHRP, as determined by both a newly established immunoradiometric assay using recombinant human PTHRP(1-87) as the standard and an RIA using an antibody against PTHRP(109-141), was increased by IL-2 but not by IL-1, IL-3, IL-4, or IL-6. The IL-2-induced increase in PTHRP secretion was completely inhibited by the addition of anti-Tac antibody. These results demonstrate that IL-2 stimulates the production and secretion of PTHRP by HTLV-I-infected T cells through specific binding to IL-2 receptor and that the effect of IL-2 is mediated by a posttranscriptional as well as a transcriptional mechanism. It is suggested that IL-2 may be involved in an auctocrine/paracrine fashion not only in the proliferation of HTLV-I-infected T cells but also in the enhanced production and secretion of PTHRP and thus the development of hypercalcemia in ATL patients.

Relationship between the anti-HTLV-1 antibody level, the number of abnormal lymphocytes and the viral-genome dose in HTLV-1-infected individuals

Two distinct diseases, adult T-cell leukemia (ATL) and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP), develop in a minor population of HTLV-1 carriers. We examined the relationship between the viral genome dose in the peripheral-blood mononuclear cells and the serological response in HTLV-1 carriers and patients with HAM/TSP. The antibody titer to HTLV-1 gag and env proteins, as well as the frequency of an antibody response to viral protein p40tax and the titer, increased with increasing viral genome dose. However, the number of abnormal lymphocytes was not directly related to the host viral load. Patients with HAM/TSP generally showed a higher genome dose than healthy carriers and also had higher antibody titers than healthy carriers with the same HTLV-1 load, supporting the existence of an augmented immune response in these patients. These findings suggest that the antibody titer to HTLV-1 genome products, and not the number of abnormal lymphocytes, intimately reflects the approximate viral load in HTLV-1-infected individuals.

Apparent ineffectiveness of natural killer cells vis-à-vis retrovirus-infected targets

The role of NK cells in the defense against retroviral infections is ill defined. The discovery of the pathogenic human retroviruses and their epidemic spread have made more urgent a better understanding of how such infections may be naturally controlled. Therefore, a systematic study was undertaken to determine whether NK cells obtained from healthy individuals are able to recognize and lyse target cells that have been infected with HTLV-I, HTLV-II, or HIV. The studies demonstrated that NK cells can recognize retrovirus-infected cells as evidenced by rapid conjugation, but that neither freshly isolated, nor IL-2 stimulated cells cause lysis of such targets. As has been reported for NK-resistant tumor cells, removal of sialic acid residues rendered the retrovirus-infected target cells vulnerable to NK cell attack. Although these data do not suggest that boosting natural immunity would be a useful treatment modality for patients with AIDS or HTLV-related diseases, the observations may help to explain why the small number of cells that harbor retroviruses in patients with subclinical infection are not eliminated.

Immunologic correlates of spontaneous lymphocyte proliferation in human T-lymphotropic virus infection

Previously we showed that mononuclear cells from about half of human T-lymphotropic virus (HTLV)-seropositive persons exhibit spontaneous proliferation in vitro. We sought to determine if proliferation was associated with other immunologic changes characteristic of HTLV infection. The parameters assessed were (1) percentages of lymphocytes expressing CD4 and/or CD25 (interleukin-2 receptor), (2) serum levels of soluble CD25, (3) serostatus for other viruses, (4) anti-HTLV antibody levels, and (5) HTLV type determined by polymerase chain reaction or serologic reactivity with type-specific peptides. The proliferation+ HTLV (PROL+) group, proliferation HTLV (PROL-) group, and control group showed similar percentages of CD4+, CD25+, and CD4+CD25+ lymphocytes; serum levels of soluble CD25 were also similar. Antibodies to cytomegalovirus, hepatitis B core, and hepatitis C were present in similar proportions of PROL+ and PROL+ groups. However, a significant association was found between spontaneous proliferation and anti-HTLV antibody levels; sera from 67% of PROL+ persons, but only 18% of PROL- persons, required dilution to yield absorbance values within the linear range of the anti-HTLV antibody assay. In the PROL+ group, persons whose sera required the most dilution had proliferative responses significantly higher than those whose sera required no dilution. The PROL+ and PROL groups were similar with regard to the relative distribution of HTLV-I and HTLV-II infection. These findings indicate that HTLV-related spontaneous lymphocyte proliferation is related to levels of circulating anti-HTLV antibodies, and characterizes both HTLV-I and HTLV-II infection.

Normal expression of p55 interleukin 2 receptor (CD25) by lymphocytes from former blood donors seropositive for human T lymphotropic virus

Dysregulated expression of the p55 interleukin 2 receptor (CD25) is characteristic of adult T cell leukemia (ATL) associated with human T lymphotropic virus (HTLV) infection. In order to determine if similar changes characterize HTLV infection in the apparent absence of ATL, CD25 expression by peripheral blood lymphocytes from HTLV-seropositive former blood donors was measured using a sensitive dual-color cytofluorometric assay. When comparing the HTLV-seropositive group (N = 19) and a seronegative control group (N = 20), no significant differences were observed in either the proportions of the major lymphocyte subsets (CD3, CD4, CD8, CD19, CD16/56) coexpressing CD25 or the phenotypic distribution of CD25+ cells among these lymphocyte subsets. Similarly, the total percentages of CD3, CD4, CD8, and CD19 cell subsets were unchanged; however, the percentage of CD16/56+ cells was significantly decreased in the HTLV group and reflected a decrease in the percentage of CD16/56 cells lacking CD25. These findings indicate that HTLV infection without ATL is characterized by normal CD25 expression by lymphocytes and a decreased percentage of lymphocytes with a phenotype characteristic of natural killer cells.

Inflammatory lesions of peripheral nerve in a patient with human T-lymphotropic virus type I--associated myelopathy

In a patient with tropical spastic paraparesis associated with a positive titer for human T-lymphotropic virus type I, electrophysiological study detected a mixed, axonal and demyelinating, multifocal neuropathy. Perineural and perivascular infiltrates, moderate axon loss, wallerian degeneration, and demyelinating lesions of isolated fibers were present in the nerve biopsy specimen. These inflammatory lesions resembled those found in the central nervous system of patients with tropical spastic paraparesis.

An autopsy case of human T-lymphotropic virus type I-associated myelopathy

This report describes the first autopsy case of human T-lymphotropic virus type I (HTLV-I)-associated myelopathy (HAM). The disease mainly affected the spinal cord, particularly the lateral and anterior columns, where loss of myelin and axon was observed. The changes were bilateral and occurred mainly along the tract. Perivascular and parenchymal infiltration with lymphocytes and macrophages, as well as astrocytosis, were observed in the white and grey matters of the spinal cord. Blood vessels in the spinal cord and in the subarachnoid space of the spinal cord showed hyalinoid thickening of media and adventitia associated with infiltration of lymphocytes. These findings are similar to those of tropical spastic paraparesis (TSP).

HTLV-I-associated T-cell leukemia/lymphoma in Israel

Human T-cell lymphotrophic virus Type I (HTLV-I)-associated adult T-cell leukemia/lymphoma (ATL) is a relatively new clinical entity. The disease is endemic in southwestern Japan, the Caribbean basin, the southeastern United States and Africa. We report the identification of this disease in Israel and review previous cases of HTLV-I infection and ATL in this region. The disease was initially indolent and later clinically aggressive, characterized by hypercalcemia, osteolytic bone lesions, leukemic skin and organ infiltration and opportunistic infection.

Lymph node enlargement in patients with unsuspected human immunodeficiency virus infections

The histologic findings in lymph nodes were used to identify eight patients, who are not in a high-risk group, with human immunodeficiency virus (HIV) infection. In order to determine the specificity of these findings, the histologic and clinical findings in these patients were compared with the histologic and clinical findings in 40 patients whose lymph nodes exhibited reactive follicular hyperplasia and who received biopsies before 1981. While a definitive diagnosis of HIV infection cannot be made from the histologic changes in lymph nodes because the organisms cannot be identified, our findings indicate that HIV infection can be suggested, and appropriate testing warranted, when marked reactive follicular hyperplasia with mononuclear cells (and a small number of neutrophils) in parafollicular sinuses is found in a patient with unexplained lymph node enlargement at two or more noncontiguous, noninguinal sites for several months, with or without systemic symptoms.

Magnetic resonance imaging in an HTLV-I antibody positive patient with tropical spastic paraparesis

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Influence of cyclosporin A on growth of an acute T-cell leukaemia in PVG rats

Our objective was to examine the effect of cyclosporin A (CsA; 25 or 12.5 mg/kg) on growth of an acute (Roser) T-cell leukaemia in male PVG rats. The leukaemic blasts were shown (by immunocytochemical analysis) to have a mature, T-helper-cell phenotype, i.e., OX-19 (CD5) +/- , W3/25 (CD4)+, OX44+, MHC-class I+, OX-26+, corresponding to a population comprising 5% of normal rat medullary thymocytes. Animals received 20 X 10(3) viable tumour cells intramuscularly (day 0) and were given either CsA (25 or 12.5 mg/kg) or drug vehicle by gavage from day 0 or day 14, by which latter time leukaemic blasts normally appeared in the circulation. Administration of the higher dose of CsA from day 0 or day 14 significantly delayed the appearance of leukaemic cells in the peripheral circulation, whereas treatment with 12.5 mg/kg was without significant effect. CsA whole blood levels on day 17 were twice as high in leukaemic rats as in normal controls. Leukaemic infiltration of the spleen and the liver was reduced on day 17 after 25 mg/kg CsA, but no such effect was observed in lymph nodes or kidneys. A heterogeneous, host "reactive" cell population, which developed in response to the leukaemia, was inhibited by CsA, indicating that the effect of the drug was probably not mediated by host defence mechanisms. In CsA-treated leukaemic animals, there was biochemical evidence of synergistic impairment of glomerular and tubular function.

Serial transplantation of an HTLV-I-transformed hamster lymphoid cell line into hamsters

A hamster lymphoid cell line, HCT-2, transformed by human T-cell leukemia virus type I (HTLV-I) was serially transplanted for 9 passages in newborn hamsters. A total of 34 newborn hamsters inoculated intraperitoneally (i.p.) with 0.2-2 X 10(7) HCT-2 cells developed fatal lymphomas with dissemination to various organs within 5-10 days. The growth of i.p. inoculated HCT-2 cells was found to be dependent on the age of recipients: all 21 suckling hamsters inoculated when aged 5-10 days succumbed to disseminated lymphomas within 6-7 days, while 4 of 12 older hamsters inoculated at the age of 15-25 days developed less extensive disease with signs of tumor regression. To investigate the effect of immunosuppression on host resistance, 3 adult hamsters treated with anti-thymocyte serum were inoculated i.v. with 2-4 X 10(7) HCT-2 cells; all 3 developed fatal leukemias in 5-7 days. Irrespective of whether HCT-2 cells were inoculated into newborn, suckling, or adult hamsters, histopathological findings were similar, with frequent involvement of liver, spleen, lungs, kidneys, lymph nodes, blood, and bone marrow. Cells harvested from tumors and peripheral blood of some tumor-bearing hamsters could be readily recultured as cell lines. Chromosome analysis and Southern blot hybridization showed that tumors were caused by growth of HCT-2 cells.

Characterization of the spectrum of postthymic T-cell malignancies in Taiwan. A clinicopathologic study of HTLV-1-positive and HTLV-1-negative cases

Postthymic T-cell malignancy shows marked geographic, clinicopathologic, and prognostic diversity. The frequency and spectrum of T-cell malignancies in Taiwan were investigated. Fifty-two patients (35 male and 17 female) with a median age of 49 years, were consecutively encountered between October 1983 and April 1987; these accounted for 39% of non-Hodgkin's lymphoma cases seen in our institutions. Ten patients (19.3%) had adult T-cell leukemia/lymphoma (ATL) associated with human T-cell leukemia virus (HTLV-1). Patients with ATL had disease similar to that reported from southwestern Japan and the Caribbean. They had frequent skin lesions (60%), hypercalcemia (40%), and a rapid clinical course with a median survival of 1.3 years. The 35 HTLV-1-negative peripheral T-cell lymphomas (PTL) were similar to PTL in western countries, manifesting frequent visceral, cutaneous, and vascular tropisms. Marrow involvement was documented at presentation in 39% and Stage III/IV disease in 80% of the PTL patients. The histology of PTL usually expressed prominent reactive features which is distinct from that in ATL. Several subcategories could be defined: Hodgkin's-like PTL in nine patients, T-zone lymphoma in three, angioimmunoblastic lymphadenopathy-like lymphoma in one, Lennert's lymphoma in three, and angioinvasive lymphoma in four. Two HTLV-1-negative PTL had neoplastic cells with clover-shaped nuclei and were designated as ATL-like. Morphologic classification based on the modified Working Formulation showed prognostic correlation, with median survival of less than 6 months for large cell/immunoblastic PTL, compared with 5 years for patients with small/medium cell PTL. Both low- and high-grade PTL seem to represent an incurable disease. Classical cutaneous T-cell lymphoma (seven cases) is relatively unusual in Taiwan, compared with the frequency of PTL. Post-thymic T-cell malignancies in Taiwan include HTLV-1-positive and HTLV-1-negative diseases, both of which have a poor prognosis and resemble similar T-cell malignancies in the East and West.

S-100 beta positive T cell leukemia

We reported a peculiar case with T cell leukemia. The patient was a 34-year-old woman showing extensive splenomegaly and marked leukemic cell proliferation and running a rapid fatal clinical course. The leukemic cells were morphologically ordinary lymphocytes showing suppressor/cytotoxic(s/c) T cell phenotypes and containing S-100b protein. Southern blot analysis revealed rearrangement of the beta chain genes of the T cell receptor (TcR) of the leukemic cells. Because these phenotypic and morphologic features were identical with those of S-100 beta+T lymphocytes (S-100 beta +TL) in normal human peripheral blood, we regarded this case as S-100 beta +T cell leukemia. We discussed clinicopathological features of S-100 beta +T cell leukemia/lymphoma by assessing similar cases reported so far. S-100 beta +T cell leukemia/lymphoma is a new type of s/c T lymphocytic leukemia/lymphoma with aggressive features.

A soluble-factor(s) secreted by a human skin cancer cell line supports clonal growth of adult T-cell leukemia cells

Leukemic cells from four out of eight patients with adult T-cell leukemia (ATL) were successfully grown by cocultivation with HSC-I cells, a human skin cancer cell line, in the presence of interleukin-2. Three of these four cultures of growing cells showed rearrangement of the T-cell receptor beta-chain gene like the original leukemic cells in vivo, and also showed conservation of the patterns of HTLV-I integration of the original leukemic cells in vivo. Cell-to-cell contact between HSC-I cells and leukemic cells was not necessary for growth of the leukemic cells. The results indicate that some soluble growth factor secreted by HSC-I cells and interleukin-2 are required for the in vitro growth of leukemic cells from some patients with adult T-cell leukemia.

Defective human immunodeficiency virus (HIV) particles produced by cloned cells of HTLV-I-carrying MT-4 cells persistently infected with HIV

Persistently HIV-infected cell lines were isolated from surviving and proliferating cells after infection of HTLV-I-carrying MT-4 cells with cell-free human immunodeficiency virus (HIV); HTLV-IIIB and LAV. The media of the cloned cell cultures did not cause HIV infection of MT-4, MOLT-4, TALL-1, or HL-60 cells. Most of the constituents of the virus in the media were env proteins and many defective doughnut-shaped particles released from the cells were identified by electron microscopy.

HTLV-I-induced lymphoma mimicking Hodgkin's disease. Diagnosis by polymerase chain reaction amplification of specific HTLV-I sequences in tumor DNA

A patient with a localized HTLV-I-associated lymphoproliferative disease that was misdiagnosed as Hodgkin's disease is presented. The patient's serum was negative for HTLV-I antibodies by enzyme-linked immunosorbent assay (ELISA), Western blot, and radioimmunoprecipitation. Tumor tissue DNA was negative for HTLV-I by Southern blotting but was positive for distinct HTLV-I sequences when subjected to DNA amplification using the polymerase chain reaction. We conclude that the clinical and pathologic diagnosis of HTLV-I-related lymphoma can be difficult and can be confused with Hodgkin's disease. Extremely sensitive molecular biological techniques may be required to establish a diagnosis of HTLV-I-induced lymphoma.

Clinical and molecular parameters of HTLV-I infection

The elucidation of the spread of HTLV-I through high-risk groups and the finite but real incidence of HTLV-I seropositivity in normal blood donor populations in the United States indicates that blood and blood products should be screened for this infectious agent. Because of the ability of the provirus to exist in a quiescent state and the long lag time between exposure and seroconversion, it may be necessary to screen potential blood donors for integrated sequences by gene amplification methodologies in addition to standard serologic testing to protect the blood supply. The detection of the HTLV-I virus often requires multiple modes of testing, even in ATL patients. We have characterized by gene amplification several HTLV-I positive lymphoma patients who were seronegative. We have also identified by radioimmunoprecipitation assays intravenous drugs abusers who have antibody solely to the nuclear pX gene product and who do not, therefore, test positive in an ELISA assay prepared from purified virion proteins. All HTLV-I positive patients need to be counseled about the biohazard status of their body fluids. The fact tha only 1 to 2 per cent of HTLV-I infected persons have any diagnosable disease, coupled with the knowledge that the mean time for the onset of clinical manifestations is some 20 to 30 years following conversion to seropositivity, indicates that this is not a virulent pathogen or a highly transforming virus. These epidemiologic data support the notion of HTLV-I's role as a mitogen or first lesion in a multistep pathway to malignancy. These data are also consistent with the idea of rare random cis-activation of one of many cellular oncogenes following a fortuitous integration event.

Adult T cell leukemia-like disease experimentally induced in rabbits

An HTLV-I-transformed T cell line, obtained from the peripheral blood of a virus-infected (B/J X Chbb:HM) F1 rabbit, was able to kill syngeneic newborn rabbits within 7 days, when inoculated intraperitoneally at a dose of 1 X 10(8) cells. Inoculation of 1 X 10(7) cells killed or rendered moribund 50% of inoculated animals, while surviving animals exhibited cell-mediated cytotoxic activities against the transformed cells. The peripheral blood leukocyte counts increased in all surviving animals, in association with appearance of abnormal lymphocytes with convoluted or lobulated nuclei. Pathological examination of animals that died one week post-inoculation revealed no tumors in the abdominal cavity, but accumulation of ascites containing abnormal lymphocytes. Histological examination showed leukemic infiltration in the liver, lungs, spleen and mesenteric lymph nodes. The same cell line was also able to kill syngeneic adult rabbits in 8-10 days when inoculated intravenously, but not intraperitoneally, at a dose of 1 X 10(8) cells. Leukemic infiltration was observed in the major organs of these animals. Adult animals which were already virus carriers were resistant to this lethal inoculation. This rabbit ATL-like disease may prove to be useful as an experimental model for acute adult T cell leukemia.

Leukemias and lymphomas of thymic differentiation

Neoplasms of thymic T-cell derivation include two closely related malignancies: T-cell acute lymphoblastic leukemia (T-ALL) and T-cell lymphoblastic lymphoma. The recognition of these tumors as distinct biologic entities dates back to the early 1970s, when patients with these diseases were found to have tumor cells that formed spontaneous rosettes with sheep erythrocytes. In the last decade, however, the growth of new technologies and availability of new reagents has enabled us to characterize this group of diseases with more precision. When studied with a panel of monoclonal antibodies, there is tremendous phenotypic diversity in the types of T-cell leukemias that are encountered. In spite of this diversity, a few general facts have become apparent. To a first approximation, thymic T-cell malignancies can be related to stages of normal T-cell development. Surprisingly, in spite of the overall similarity between T-ALL and T-lymphoblastic lymphoma, the antigenic phenotypes encountered suggest a biologic difference between these two diseases. Although there is not currently any single reagent that permits recognition of T-ALL or lymphoblastic lymphoma in all cases, a combination of technologic approaches using conventional morphology and histochemistry, immunologic studies, and, in some cases, newer genetic studies should permit great precision in the definition of this disease. The clinical picture of T-cell ALL or lymphoblastic lymphoma has traditionally been one of a poor prognosis disease with high WBC count, bulky adenopathy, and mediastinal mass. Although encountering this clinical presentation should suggest the T-cell phenotype, not all patients with T-cell leukemia will fit this stereotype. Clinical studies have also served to provide support for the expanding biologic definition of T-cell neoplasia, particularly insofar as it has been demonstrated that patients with T antigen-positive but E rosette-negative ALL behave like other patients with T-cell disease. In short, patients with thymic T-cell malignancies not only have distinctive biologic characteristics to their blasts, but also have a distinctive pattern of clinical presentation, response to therapy, and sites of relapse. These differences have prompted the search for specific therapies and also directed approaches to understanding the variable clinical outcome of patients with these malignancies.

T-cell lymphomas and leukemias of post-thymic differentiation

This article describes the heterogeneity of post-thymic T-cell malignancies and correlates specific clinicopathologic entities with morphology and immunophenotype. Peripheral T-cell lymphomas are subclassified into six main histologic types with different prognoses. Special attention is given to the theme of proposed origin and spread of T-cell malignancies.

Adult T-cell leukemia by probable horizontal transmission from husband to wife

A 60-year-old housewife was affected with adult T-cell leukemia (ATL) 10 years after her husband died of T-cell lymphoma, which was retrospectively diagnosed as ATL. She had never had a blood transfusion nor any indication of infection by human T-cell lymphotropic virus type I (HTLV-I) from her parents. The report suggested the wife to have developed ATL by horizontal transmission of HTLV-I from her husband 31 years after their marriage.

Cutaneous-type adult T-cell leukemia/lymphoma. A unique clinical feature with monoclonal T-cell proliferation detected by Southern blot analysis

A 60-year-old woman suffered from multiple subcutaneous nodules with a self-limited clinical course. High titer of the antibody against the adult T-cell leukemia/lymphoma (ATL)-associated cell antigen was detected and atypical lymphocytes were present in less than 1% of the peripheral leukocytes. Tumor cells were identified by the molecular biology technique Southern blot analysis, which showed monoclonal cell expansion of the helper/inducer T cells integrated with human T-cell lymphotropic virus type I/adult T-cell leukemia virus. This patient was diagnosed as having the cutaneous type of smoldering ATL in a very early stage. In this case, only gene analysis of the skin lesion could facilitate making an early differential diagnosis of ATL from other lymphoproliferative diseases, including nonviral cutaneous T-cell lymphoma and benign lymphoid hyperplasia.

Gene rearrangements of T cell receptor beta and gamma chains in HTLV-I infected primary neoplastic T cells

Rearrangements of T cell receptor beta and gamma chain (T beta and T gamma) genes were analyzed by Southern blot method in samples from 30 patients with adult T cell leukemia (ATL) and 17 patients with non-ATL T cell neoplasms. The DNA probes used were the constant and joining region of T beta gene and the joining region of T gamma gene. Rearranged bands of T beta gene on one or both allelic chromosomes were detected in all neoplastic T cells, even those of smoldering ATL, in which only a small percentage of peripheral blood T cells were detected as leukemic. T gamma gene was rearranged in the cells of all but one patient, the exception being one ATL patient. In order to test whether any given variable region (V) of T beta gene was expressed in ATL cells, two functionally rearranged V beta sequences of ATL were compared with a V beta sequence from T cells acute lymphoblastic leukemia cells. No significant homologies were noted among the three deduced gene product amino acid sequences, confirming that T beta molecules of ATL cells contained no specific structures in common. The observed heterogeneity of T beta and T gamma gene rearrangements in ATL cells further supported these findings.

Human T cell lines established from the cerebrospinal fluid of patients with human T lymphotropic virus type I-associated myelopathy (HAM)

T cell lines were established from the cerebrospinal fluid (CSF) lymphocytes of two patients with human T lymphotropic virus type I (HTLV-I)-associated myelopathy (HAM). These two interleukin-2 (IL-2)-dependent T cell lines have been cultured for more than 8 months without any accessory cells. The surface phenotype of these cells was CD2(+), CD4(+), CD8(-), Ia(+) and Tac(+). Southern blot hybridization analysis revealed the presence of HTLV-I provirus in these cells and C-type retrovirus particles were identified by electron microscopy. These findings indicate the presence of HTLV-I infected helper T lymphocytes in the CSF of the patients with HAM. These HTLV-I(+) T cell lines may be valuable for investigating the possible neutrotropism of HTLV-I and the role of HTLV-I in the pathogenesis of HAM.

Upper respiratory tract involvement in adult T-cell leukemia

Adult T-cell leukemia (ATL) is characterized by peripheral lymph node enlargement, hepatosplenomegaly and skin lesions. The association of local mass lesions of other organs with ATL is extremely rare. This report describes a 57-year-old woman with chronic type ATL with associated local tumor masses in the nasal cavity, paranasal sinuses and larynx as well as skin infiltration. Histologic investigation of the skin lesion and nasal mucosa revealed non-Hodgkin lymphoma, diffuse, mixed type. Her chief complaints were progressive dyspnea and hoarseness. Leukemic cell masses in her upper respiratory tract caused narrowing of the airway, which was responsible for her complaints.

The screening of cattle with potential for developing leukemia by using monoclonal antibody against bovine leukemia cells

Tumor cells from cattle with enzootic bovine lymphosarcoma (EBL) have a tumor-associated antigen (TAA) which is distinct from bovine leukemia virus (BLV)-induced antigens. We were able to sacrifice 8 TAA-positive cattle with no clinical signs of EBL and to examine whether or not they had gross or histological tumors. At necropsy, 4 animals had tumors macroscopically. Three animals had no tumors histologically but had initial lesions showing follicular hyperplasia and had the TAA on affected lymph nodes. The remaining one showed medullary hyperplasia in the spleen but there were no findings of tumors. These results suggest that most BLV-infected cattle which are TAA-positive but have no clinical signs of EBL, do have tumors and have a higher potential for developing EBL in the future when compared to BLV-infected but TAA-negative cattle.

Spastic paraparesis and HTLV-I infection in Peru

Three of 6 patients with spastic paraparesis in Lima, Peru, were found to have antibodies to human T-lymphotropic virus type I (HTLV-I). Blood and cerebrospinal fluid antibodies were confirmed by Western blot analysis. Multilobulated lymphocytes in blood and cerebrospinal fluid of the index case stained with monoclonal antibodies for T-helper cells and for T10, an activation marker. Blood mononuclear cells from patients with HTLV-I-associated myelopathy showed spontaneous proliferation in culture, evidence of interleukin-2 receptors, and decreased natural killer cell activity.