HTLV-I Induced Extranodal Lymphomas

HTLV-I induced not only nodal but also primary extranodal lymphomas. In this report we describe 12 patients with HTLV-I induced extranodal T-cell lymphoma collected from the literature and our institute experience. There were 5 males and 7 female patients of middle age positive for HTLV-1 antibody. The sites of primary tumor were gastrointestinal, Waldeyer's ring, skin, facial sinuses, and the pleura. All of these were histologically diffuse lymphomas and most of them were found to be a helper/inducer T-cell phenotype, showing integration of HTLV-I proviral DNA. Late leukemic changes and skin infiltration often occurred, but hypercalcemia was rare. Survival time varied from 4 to 35 months, and late organ infiltrations were common. These HTLV-I induced extranodal lymphomas were compared with HTLV-I unrelated extranodal lymphomas or HTLV-I induced nodal lymphomas (lymphoma type ATL). Between 1981 and 1990, we had 110 ATL patients and of these, 5 (4.6%) were HTLV-I induced primary extranodal lymphomas. The frequency of HTLV-I induced extranodal lymphoma might be much higher than expected because until now attention has not been paid to this entity. From the present review, it is suggested that HTLV-I could cause primary extranodal lymphoma which may have some different characteristics from other types of lymphoma. Therefore, patients with T-cell extranodal lymphomas should be investigated further for the presence of HTLV-I antibody and the tumor cells should be examined for the integration of HTLV-I proviral DNA using Southern blot analysis. However, this is sometimes difficult to detect with small specimens and in these cases the PCR method for detection of HTLV-I proviral DNA is worthwhile doing. It should be stressed that characterization of a monoclonal T-cell tumoral expansion with the integration of HTLV-I proviral DNA can be done by surface marker studies and gene analysis at the primary sites in patients with T-cell lymphoma and HTLV-I antibody. Further collection of cases with HTLV-I induced primary extranodal lymphoma is necessary in order to elucidate the clinical characteristics of this rare variant of ATL more precisely.     

Chromosomal abnormalities in non-Hodgkin lymphoma with peripheral T-cell type: effect of HTLV-I infection

Cytogenetic studies were done in lymph node and peripheral leukemic cells from sixteen patients with non-Hodgkin lymphoma with peripheral T-cell type. Ten patients were positive for human T-cell leukemia virus I (HTLV-I) proviral DNA in tumour cells and six were negative. The former group had a higher tendency for leukemic conversion and poorer prognosis than the latter. However, no definite difference on the numerical and structural chromosomal abnormalities between these two groups was found. The most frequent chromosome abnormalities: 14p+, 14q+ and No. 6 abnormalities were detected in both groups. These results may indicate that HTLV-I does not play a specific role in chromosome abnormalities of non-Hodgkin lymphoma with peripheral T-cell type.     

IgG-κ-Type Plasmacytoma Secreting Salivary-Type Amylase in Adult T-Cell Leukemia

A IgG-κ-type plasmacytoma secreting salivary-type amylase ectopically is reported in a patient with smouldering adult T-cell leukemia(ATL). The patient had plasmacytomas in the distal region of the right femur, the proximal region of left tibia, and the left paranasal sinus. Both his serum and urine contained high levels of amylase. The presence of IgG-κ and S-type amylase in the plasmacytoma cells was confirmed immunocytochemically. In addition, he was also positive for the antibody against the human T-cell leukemia virus type I (HTLV-I), and had abnormal lymphocytes with convoluted nuclei(ATL cells) in the peripheral blood. The monoclonal integration of HTLV-I proviral DNA was demonstrated in the leukemic cells of the peripheral blood, but not in the plasmacytoma cells. Our case suggested that not only can HTLV-I infection play a role in the development of ATL, but may also induce a B-cell malignancy in an indirect manner, and even an ectopic amylase producing plasmacytoma.     

Serial Transplantation of Adult T Cell Leukemia Cells into Severe Combined Immunodeficient Mice

The precise mechanism of the neoplastic cell growth of adult T cell leukemia (ATL) still remains unclear. In the present study, we have succeeded in serial transplantation of ATL cells from a patient into severe combined immunodeficient (SCID) mice. In this model, we found that only a leukemic cell clone from an ATL patient could be successively transplanted into SCID mice, although it was difficult to maintain leukemic cell clones in vitro , suggesting that the microenvironment provided by SCID mice is suitable for leukemic cell growth. We could not detect human T cell leukemia virus type I (HTLV-I) mRNA or interleukin 2 (IL-2) mRNA in either the tumor cells growing in mice or the original leukemic cells. Thus, it appears that neither HTLV-I viral expression nor the IL-2 autocrine mechanism is directly involved in the neoplastic cell growth of fresh ATL cells as well as HTLV-I-infected cell lines, at least in SCID mice. In addition, we could passage frozen cells and obtain a large number of expanded leukemic cells in this model. Such a serial transplantation model, which can avoid the changes in the nature of leukemic cells that are frequently observed in in vitro culture, and which can propagate leukemic cell clones, would be very suitable not only to study the mechanism of neoplastic cell growth, but also to test potential therapeutic agents for ATL.     

Production of monoclonal antibodies against HTLV-I proteins recognizing surface epitopes of live infected cells

The proteins of HTLV-I virus, the only human retrovirus implicated in the etiopathogenesis of the T-cell leukemia, were previously studied with the use of monoclonal antibodies. Different groups have produced specific monoclonal antibodies that recognized the core proteins of the virus p19 and p24 and in one case a monoclonal specific of a gp21 protein. All these antibodies were shown to react with the virus-producing fixed cells. We also developed a battery of antibodies against p24 and p19 antigens from HTLV-I virus but the anti-p19 monoclonal antibodies happened to recognize epitopes exposed on the surface of live HTLV-I infected cells. One of the monoclonal antibody that bound to the surface of HTLV infected cells recognized a protein of an approximate mol. wt of 33 kilodalton (KD). These antibodies that bound to the live cells should be precious tools to study leukemic patients with T-cell leukemia and the evolution of the live cell populations during the course of the disease.     

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.     

Inhibitory effects of human interferons on the immortalization of human, but not rabbit, T lymphocytes by human T-lymphotropic virus type-I (HTLV-I).

The effects of human interferon (IFN)-alpha, -beta, and -gamma on the immortalization of human and rabbit lymphocytes by human T-lymphotropic virus type-I (HTLV-I) have been investigated. The immortalization of human peripheral-blood lymphocytes co-cultured with lethally X-ray-irradiated HTLV-I-producer cells, MT-2, was blocked in the presence of more than 40 u/ml human recombinant IFN-alpha or more than 200 u/ml human natural type IFN-beta. However, rhIFN-gamma did not block immortalization by HTLV-I even at higher doses. On the other hand, the presence of high doses of hIFN-alpha, -beta, or -gamma did not exhibit any biological effect on the immortalization of rabbit peripheral-blood lymphocytes co-cultured with lethally X-ray-irradiated MT-2 cells. Integration of the full length of HTLV-I genome was detected in every transformant by Southern blot analysis. All cell lines established were CD4+/CD8 divided by T-lymphocytes, except for one cell line of CD4+/CD8+. Morphologically intact HTLV-I production was observed by electron microscopy in these cells. Our results indicate that HTLV-I released under the strongly suppressed condition in the presence of IFNs remains active and able to immortalize T lymphocytes. It is also suggested that immortalization of human T lymphocytes by HTLV-I can be inhibited by the antiviral state induced by the treatment with low doses of hIFN-alpha and -beta, whereas immortalization of rabbit T lymphocytes is not inhibited because of the species specificity of hIFNs.     

Adult T-Cell Leukemia/Lymphoma and Cluster of HTLV-I Associated Diseases in Brazilian Settings

We studied the transmission routes of human T-cell lymphotropic virus type I (HTLV-I) within families of 82 Brazilian patients diagnosed with adult T-cell leukaemia/lymphoma (ATL). Diagnosis of ATL in 43 male and 39 female patients was based on clinical and laboratory criteria of T-cell malignancy and detection of HTLV-I monoclonal integration. Samples were tested for HTLV antibodies and infection was confirmed as HTLV-I by Western Blot and/or polymerase chain reaction (PCR) assays. Overall 26/37 (70%) of mothers, 24/37 (65%) of wives, 8/22 (36%) of husbands, 34/112 (30%) of siblings and 10/82 (12%) offspring were HTLV-I infected. In 11 ATL patients, mothers were repeatedly HTLV-I seronegative, but HTLV-I pol or tax sequences were detected in 2 out of 6 cases tested by PCR. ATL patients with seronegative mothers related the following risk factors for HTLV-I infection: 6 were breast-fed by surrogate mothers with unknown HTLV-I status, 4 had a sexually promiscuous behaviour and 1 had multiple blood transfusions at a young age. Familial aggregation of ATL and other HTLV-I associated diseases such as HTLV-I myelopathy (HAM/TSP) and or uveitis, ATL in sibling pairs or in multiple generations was seen in 9 families. There were 6 families with ATL and TSP sibling pairs. In 3 families at least one parent had died with lymphoma or presenting neurological diseases and 2 offspring with ATL. Further to the extent of vertical and horizontal transmission of HTLV-I infection within ATL families, our results demonstrate that mothers who provide surrogate breast-milk appear to be an important source of HTLV-I transmission and ATL development in Brazil.     

Novel Interleukin-2 Dependent T-Cell Line Derived from Adult T-Cell Leukemia Not Associated with Human T-Cell Leukemia Virus Type I

A novel interleukin-2 (IL-2)-dependent T-cell line, WHN2, was established from a patient with adult T-cell leukemia (ATL) not associated with human T-cell leukemia virus type I (HTLV-I). Neither the original leukemic cells nor the WHN2 cells showed proviral integration in their cellular DNAs by Southern blot analysis. The surface phenotype showed that both the original leukemic cells and the WHN2 cells had a common phenotype of ATL, i.e., positive for CD2, CD4, human leukocyte antigen DR (HLA-DR) and CD25, but negative for CD8, a characteristic of helper/inducer T-cells. Most of the chromosomal abnormalities of the original leukemic cells were maintained in the WHN2 cell line. Furthermore, Southern blot analysis of the T-cell receptor β -chain gene rearrangement revealed that the original leukemic cells and WHN2 cell line had identical patterns, suggesting that the WHN2 cell line was truly derived from the original leukemic cells. Dose-dependent growth on IL-2 was demonstrated, and at the maximal stimulation, the number of cells doubled within three days. This IL-2-dependent growth was inhibited by the simultaneous existence of anti-IL-2 receptor a and β chain antibodies. These results indicate that the character of the WHN2 cell line is similar to that of the cell lines derived from ATL associated with HTLV-I. Thus, the HTLV-I-negative ATL cell line, WHN2, should be useful in the comparative study of the pathogenesis of ATL associated with or without HTLV-I.     

In vitro infection of CD4+ T lymphocytes with HTLV-I generates immortalized cell lines coexpressing lymphoid and myeloid cell markers.

The human T cell leukemia/lymphoma virus (HTLV-I) is the etiologic agent of adult T cell leukemia (ATL). CD4+ lymphocytes are the preferential targets of infection, even though other cell types can be infected in vitro by the virus. Although ATL cells show CD3 and CD4 surface markers, some ATL-derived cell lines were reported to express also myeloid antigens. In order to analyze possible phenotypic changes induced by HTLV-I after infection of human lymphocytes, CD4+ cells were isolated from peripheral blood of three healthy donors, by separation through immunomagnetic beads. CD4+ lymphocytes were then infected by coculture with irradiated HTLV-I producing MT-2 cells. The phenotypic profile of infected cells was studied by flow cytometric analysis using monoclonal antibodies against lymphoid (CD3, CD4, TCR alpha/beta) and myelomonocitic markers (CD13, CD14, CD15, CD33, CD34). The results show that HTLV-I immortalized cell lines coexpressed CD13, CD33 and lymphoid markers. No expression of CD14, CD15 and CD34 was observed. These data suggest that the presence of both myeloid and lymphoid phenotype in HTLV-I infected T cells is the results of an induction rather than a selection mechanism.     

Persistence and differentiation of HTLV-I-transformed immature T-cells in HTLV-I carrier rabbits

Two T-cell lines with immature phenotypes, CD4⁻8⁻ and CD4⁺8⁺, were found among HTLV-I-transformed T-cell lines obtained during experiments using a rabbit model of adult T-cell leukemia. Persistence and differentiation of these clones in vivo were examined by retrospectively analysing a series of cell lines from individual animals and by adoptive transfer of these cells into syngeneic hosts. The double negative cell line did not differentiate and remained double negative in adoptive transfer into neonates and in long-term in vitro culture, while the double positive cell line differentiated both in vivo and in vitro into CD8⁺ cell, as if the fate of this cell line had been predetermined. Cells of the same clone as this double positive cell line persisted for more than one year in the peripheral blood of the animal. Long-term persistence was not observed for five cell lines of CD4 single positive phenotype, which were obtained from another carrier rabbit. These results suggested that HTLV-I-transformed immature T-cells persist in neonatally infected carriers, continuously giving rise to mature T-cells harboring HTLV-I.     

The Differences between Lymphoma and Leukemia Type of Adult T-cell Leukemia

The difference between lymphoma type and leukemia type of adult T-cell leukemia (ATL) were analysed with 102 Japanese patients all positive for human T-cell leukemia virus type I (HTLV-I) antibody. They were classified into three groups on findings at first medical examination: lymphoma type cases, leukemia type cases, and mixed type (leukemia type plus lymphadeno-pathy) cases. Lymphoma type patients had several or more enlarged lymph nodes the largest of which was greater than 1 cm in diameter and with practically no abnormal lymphocytes (ATL. cells), which are characteristic of ATL, in the peripheral blood. Leukemia type patients had 10% or more ATL cells in the peripheral blood and had no detectablle lymphadenopathy Lymphoma type patients often complained of detectable lymphadenopathy, while leukemia type patients complained frequently of general fatigue and skin eruption. Mixed type patients more frequently had signs and symptoms which were characteristic of both types: lymphadenopathy and 10% or more ATL cells in the peripheral blood. Mixed type: ATL had a poorer prognosis than either lymphoma type or leukemia type. The median survival time was 3 months for mixed type patients, 10.5 months for lymphoma type patients, and 13.5 months for leukemia type patients. Complications and causes of death have also been touched upon. Clinicians are thus advised to consider ATL patients separately according to their clinical manifestations.     

In vitro susceptibility of different human T-cell subpopulations and resistance of large granular lymphocytes to HTLV-I infection

T4 subpopulation of T lymphocytes is the preferential target of infection with human T leukemia/lymphoma virus of subgroup I (HTLV-I). In this study we attempt to determine whether different T-cell subsets exhibit differences in susceptibility to virus infection. T cells from cord or peripheral blood were separated according to cell densities and T-cell surface markers by Percoll gradient and Sepharose anti-Fab immunoadsorbent affinity column (IAC), respectively. Separated T-cell subpopulations were infected with HTLV-I, by means of co-cultivation with irradiated virus producer cell lines (MT-2, TK). Percentages of HTLV-I-infected cells were assayed by immunofluorescence assay (IFA), using highly specific mouse monoclonal antibody (MAb) directed against HTLV-I p19 core protein. The results showed that different T-cell subpopulations separated either by Percoll or by IAC were susceptible to HTLV-I infection with the exception of large granular lymphocytes (LGL), which exhibit high cell-mediated natural cytotoxicity (CMNC). The susceptibility to HTLV-I infection of T cells with CMNC activity was further studied on established cell clones with LGL morphology. The results showed again that these cells were resistant to the virus infection. The present studies indicate that different T-cell subpopulations, irrespective of their size and of cell-surface markers, are susceptible to HTLV-I infection, with the exception of functionally mature LGL or of immortalized LGL clones.     

Expression of the HT462 antigen on fresh leukemic T cells and on cells of HTLV-I infected lines

We have examined expression of antigens defined by HT462 monoclonal antibody (mAb), together with other HTLV-I related antigens using phorbol 12-myristate 13-acetate treated leukemic mature T cells. Thirteen patients with adult T-cell leukemia (ATL), 3 patients in remission states of ATL and 5 patients with non-ATL were examined. All ATL cells expressed the HT462 antigen, however cells from patients in remission did not express the HT462 antigen. A low percentage of cells from 2 out of 5 patients with non-ATL mature leukemic T cells expressed the HT462 antigen, although these cells did not express other HTLV-I related antigens. Cells of HTLV-I infected human cell lines expressed the HT462 antigen. Three HTLV-I infected rat cell lines (TARS-1, TART-1, TARL-2) did not express the HT462 antigen, although cells of these lines expressed other HTLV-I related antigens. Characterization of the HT462 antigen by strip radioimmunoassay based on western blotting technique using cell lysates of HUT102 cells revealed two additional bands (p68, p35) together with previously reported proteins (gp52, p42). Only p68 was seen in western blots using cell lysates of the rat cell lines. These findings further suggest that the HT462 antigen is a cellular component induced in virus transformed human cells and not a virus encoded protein.     

Detection of HTLV-I Genome in Seronegative Infants Born to HTLV-I Seropositive Mothers by Polymerase Chain Reaction

We applied the polymerase chain reaction (PCR) method to detect gag, env and pX sequences of human T cell leukemia virus type I (HTLV-I) provirus in peripheral blood lymphocytes of seronega-tive infants born to HTLV-I seropositive mothers. Out of 22, five subjects were found to contain the HTLV-I provirus genome. Two of the five cases were judged to be negative for not only anti-HTLV-I antibodies but also the viral antigens on cultivated lymphocytes by the conventional antibody/antigen detection methods. These results indicate that PCR is of great use as a simple and highly sensitive method detect HTLV-I infection.     

A simple and reliable method for the detection and quantitation of the human T-cell leukemia virus type-I provirus in peripheral blood mononuclear cells of seropositive blood donors.

Human T-cell leukemia virus type I (HTLV-I) antibody detection has been widely used to screen HTLV-I carriers. Sometimes, however, it gives false positive or negative results. A demonstration of the HTLV-I provirus from patients' peripheral blood mononuclear cells (PBMC) should, therefore, give the crucial evidence for them being HTLV-I carriers. We established a simple and reliable method using the polymerase chain reaction (PCR) to detect one molecule of HTLV-I provirus in 100 x 10(3) PBMC, during which internal control primers for the human beta-globin gene were also employed in the same reaction tube to check the success of the amplification reaction. We can thus easily avoid any false negative judgement and quantitate the HTLV-I provirus in PBMC simply by diluting the sample before PCR. One ml blood was enough for ten or more determinations by PCR. Analysis of seropositive blood from donors demonstrated a wide range for the number of HTLV-I provirus in PBMC. The method could conveniently be used for quantitating HTLV-I proviruses and following up HTLV-I carriers to study the pathophysiology and mode of HTLV-I transmission.     

Isolation of Virus-producing Transformants from Human Gastric Cancer Cell Line, HGC-27, Infected with Human T-cell Leukemia Virus Type I

A human anaplastic gastric cancer cell line, HGC-27, showed marked degeneration with formation of multinucleated syncytia and cell detachment of nearly all cells which began 24 hr after and reached a maximum 2 to 3 days after co-cultivation with X-irradiated MT-2 cells, HTLV-I producing human cord leukocytes. Less severe degeneration without formation of syncytia was also observed in the cultures inoculated with cell-free MT-2 culture media. Morphologically altered cells began to proliferate and formed piled up colonies in some of the cultures co-cultivated with X-irradiated MT-2 cells after a long culture period. The two clones designated HGC/MT2 (Cl-1) and HGC/MT2 (Cl-2) were separated by cell cloning. HGC/MT2 (Cl-1) and HGC/MT2 (Cl-2) cells were positive for HTLV-I gag proteins (p19 and p24) and pX gene products, p40^x, as demonstrated by immunohistochemistry and immunoblotting analysis, contained HTLV-I provirus DNA, and consistently produced type C virus particles.     

Clinicopathological Features of Adult T-Cell Leukemia with CD30 Antigen Expression

Recently, several cases of adult T-cell leukemia (ATL) with CD30 antigen have been reported, but its clinical significance remains unknown. Accordingly, we studied CD30 antigen expression in ATL cases and documented the clinicopathological characteristics of these cases.

Immunohistochemical and clinical characteristics were studied in 46 patients with malignant lymphoma or benign lesions of lymphoid tissue, who had antibodies against human T-cell leukemia virus type I (HTLV-I). Monoclonal integration of HTLV-I provirus was demonstrated in the tumor cells in 36 (ATL) of the 46 cases. CD30 antigen expression was evident in seven of these 36 cases (19.4%), however it was not seen in any of the ten cases lacking the integration of HTLV-I provirus. A comparison of ATL cases with and without CD30 antigen expression revealed significantly larger numbers of abnormal lymphocytes in the peripheral blood and lower serum calcium levels in ATL expressing CD30 antigen.     

The epidemiology of HTLV-I infection

It has been 10 years since the discovery of the human T-cell lymphotropic virus type I (HTLV-I), the first human retrovirus. During the past decade, significant progress has been made in understanding the transmission of the virus and defining its geographic distribution. It has been shown conclusively that HTLV-I is a causal factor in the induction of both adult T-cell leukemia/lymphoma and HTLV-I-associated myelopathy. However, the pathogenesis of each of these conditions is not clear, and in the light of the evidence of immune dysfunction seen among carriers of the infection, it is likely that other associated diseases will be identified. The challenge in the next decade will be to develop and implement therapeutic interventions among carriers to prevent such diseases as well as to curtail transmission within endemic populations.This work is supported by a grant from the NIH, no. R37CA38430: Dr Mueller bas on American Cancer Society Faculty Research Award.     

Expression of Cytokine mRNA in Leukemic Cells from Adult T Cell Leukemia Patients

HTLV-I infection of peripheral mature T cells appears to induce the expression of cellular genes including those of some cytokines and their receptors. We examined the expression of interleukin-lα (IL-l α ), IL-l β , IL-2, IL-3, IL-4 and granulocyte/macrophage colony-stimulating factor (GM-CSF) at the mRNA level in fresh leukemic cells from 20 adult T cell leukemia patients to see whether there is any association between cytokine expression and MTLV-I expression and between their expression and clinical manifestations such as hypercalcemia or neutrophilia. IL-l α , IL-I β and IL-3 expression was observed in 3, 7 and 1 of 20 cases examined, respectively. However, there seemed to be no association between IL-1 expression and clinical manifestations. IL-2, IL-4 and GM-CSF mRNA expression was not detected. HTLV-I viral RNA expression was detected only in one case in which IL-3 mRNA was expressed in both peripheral blood and lymph node cells and a relatively high proportion of leukemic cells expressed IL-2 receptor (p55, Tac). Thus, in the present study we could not find any correlation between cytokine expression and HTLV-I expression in peripheral blood fresh leukemic cells except in one unusual case.