Human T-cell leukemia-lymphoma virus (HTLV) is in T but not B lymphocytes from a patient with cutaneous T-cell lymphoma

Safety, efficacy, and pharmacokinetics/pharmacodynamics of daclizumab (anti-CD25) in patients with adult T-cell leukemia/lymphoma

Interleukin-2 receptor α chain (CD25) is overexpressed in human T-cell leukemia virus 1 associated adult T-cell leukemia/lymphoma (ATL). Daclizumab a humanized monoclonal antibody blocks IL-2 binding by recognizing the interleukin-2 receptor α chain (CD25). We conducted a phase I/II trial of daclizumab in 34 patients with ATL. Saturation of surface CD25 on circulating ATL cells was achieved at all doses; however saturation on ATL cells in lymph nodes required 8 mg/kg. Up to 8 mg/kg of daclizumab administered every 3 weeks was well tolerated. No responses were observed in 18 patients with acute or lymphoma ATL; however, 6 partial responses were observed in 16 chronic and smoldering ATL patients. The pharmacokinetics/pharmacodynamics of daclizumab suggest that high-dose daclizumab would be more effective than low-dose daclizumab in treatment of lymphoid malignancies and autoimmune diseases (e.g., multiple sclerosis) since high-dose daclizumab is required to saturate IL-2R alpha in extravascular sites.

Predominant expression of Fas ligand mRNA in CD8+ T lymphocytes in patients with HTLV-1 associated myelopathy

To determine if Fas ligand (FasL) mediated apoptosis is involved in the pathogenesis of HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP), we examined the expression of FasL mRNA in fresh uncultured peripheral blood mononuclear cells (PBMC) from 17 Japanese patients with HAM/TSP, four adult T-cell leukemia/lymphoma (ATL) patients, three asymptomatic HTLV-1 carriers and three normal individuals. Using competitive PCR with primers specific for FasL mRNA, we demonstrated that nine of 17 HAM/TSP and one of four ATL patients expressed significant levels of FasL mRNA, whereas asymptomatic carriers, normal controls and both HTLV-1 infected and uninfected T-cell lines did not. Cell separation analysis following PCR revealed that FasL mRNA was expressed in CD8 + T lymphocytes. FasL mRNA was preferentially expressed in patients with increased proviral load and longer duration of clinical illness. These results suggest that FasL mediated mechanisms contribute to the pathogenesis of HAM/TSP.

Diffuse panbronchiolitis: case report and review of the literature

Diffuse panbronchiolitis is an uncommon disease of unknown aetiology mainly occurring in Asian races. Treatment with erythromycin acting through unclarified mechanisms is promising and may improve the poor prognosis currently associated with the disease. A case is presented illustrating how the imaging features of the disease, particularly on high-resolution computed tomography, may be used to support a diagnosis suggested on clinical grounds.

Retrovirus in salivary glands from patients with Sjögren's syndrome

AIMS

To investigate the possibility of an immune response to retroviral antigens or of detecting retrovirus in Sjögren's syndrome.

METHODS

Retroviruses were sought in labial salivary glands and peripheral blood mononuclear cells from patients with Sjögren's syndrome by immunoblotting assay, immunohistochemical assay, polymerase chain reaction (PCR), reverse transcriptase (RT) activity assay, and transmission electron microscopy.

RESULTS

Sera from five of 15 patients with Sjögren's syndrome (33%) reacted against p24 group specific antigen (gag) of human immunodeficiency virus (HIV). Labial salivary gland biopsy specimens from seven of the 15 patients with Sjögren's syndrome (47%) contained an epithelial cytoplasmic protein reactive with a monoclonal antibody to p24 of HIV. PCR was performed to detect HIV and human T lymphotropic virus type I (HTLV-I) genes from salivary gland tissues and peripheral blood mononuclear cells from patients with Sjögren's syndrome. Mn2+ dependent, Mg2+ independent RT activity was detected in the salivary gland tissues in three of 10 patients. A-type-like retroviral particles were observed in epithelial cells of salivary glands by transmission electron microscopy. Target genes for HIV and HTLV-I were not found in any of the salivary gland tissues or peripheral blood mononuclear cells from Sjögren's syndrome patients.

CONCLUSIONS

The data suggest the presence of an unknown retrovirus similar to HIV in the salivary gland which might be involved in the pathogenesis of a subpopulation in Sjögren's syndrome.

Mechanisms of Tax Regulation of Human T Cell Leukemia Virus Type I Gene Expression

During the last several years, the human T cell leukemia virus type I (HTLV-I) has become recognized as an important cause for public health concern throughout the world. HTLV-I is the causative agent of a variety of clinical diseases, including an aggressive lymphoproliferative disorder named adult T cell leukemia. HTLV-I induces pathogenicity in the infected host cell through the synthesis of a virally encoded protein called Tax. Expression of Tax is critical to the life cycle of the virus, as the protein greatly increases the efficiency of HTLV-I gene transcription and replication. Furthermore, Tax has been shown to deregulate the transcription of many cellular genes, leading to the hypothesis that the presence of Tax promotes unchecked growth in the HTLV-I-infected cell. The mechanism of Tax trans-activation of HTLV-I gene expression is not known. Tax does not bind directly to the Tax-responsive promoter elements of the virus, but appears to function through interaction with certain cellular DNA binding proteins, including activating transcription factor 2 and cAMP response element binding protein that recognize these sequences. This review summarizes some of the recent work in the field aimed at elucidating the mechanism of Tax trans-activation of HTLV-I gene expression. Copyright 1995 S. Karger AG, Basel

Molecular definition of a polymorphic antigen (LA45) of free HLA-A and -B heavy chains found on the surfaces of activated B and T cells

A monomoprhic monoclonal antibody (LA45 antibody) reactive with "a new activation-induced surface structure on human T lymphocytes" (LA45 antigen) that resembled free class I heavy chains has recently been described (Schnabl, E., H. Stockinger, O. Majdic, H. Gaugitsch, I.J.D. Lindley, D. Maurer, A. Hajek-Rosenmayr, and W. Knapp. 1990. J. Exp. Med. 171:1431). This antibody was used to clone a class I-like heavy chain (LA45 gene) from the HUT 102 tumor cell, which paradoxically did not give rise to the LA45 antigen on transfection into monkey COS cells. We show here that the LA45 gene is HLA-Aw66.2, a previously uncharacterized allele of the HLA-A locus. The previously determined LA45 sequence differs from that of HLA-Aw66.2, from HUT 102, and the CR-B B cell line derived from the same individual as HUT 102 by substitution of tryptophan for serine at position 4 in the alpha 1 domain. Transfection of HLA-Aw66.2, and of a mutant of this gene with serine 4 substituted for tryptophan, into a human B cell line (C1R) both resulted in expression of the LA45 epitope. Furthermore, we find expression of the LA45 epitope on Epstein Barr virus-transformed B cell lines as well as lectin-activated T cells, but not on long-term T cell lines or unstimulated peripheral blood T cells. The specificity of the LA45 antibody is polymorphic and the presence of the LA45 epitope is precisely correlated with the sequence arginine, asparagine (RN) at residues 62 and 63 of the helix of the alpha 1 domain. The LA45 epitope is broadly distributed, being associated with half the alleles of both HLA-A and -B loci but none of the HLA-C locus. All the results are consistent with the presence of pools of free HLA-A and -B heavy chains at the surfaces of certain cell types but not others. Such molecules are probably responsible for the HLA-associated class I alloantigens of lectin-activated T cells. We hypothesize the free heavy chains result from dissociation of beta 2-microglobulin from subpopulations of empty HLA-A,B molecules, or molecules with weakly bound peptides, that vary in size depending on cellular activation and peptide supply.

Detection of HTLV-I proviral sequences in CD30-positive large cell cutaneous T-cell lymphomas

To investigate the possibility that cutaneous T-cell lymphomas of large cell type may be associated with human T-cell leukemia/lymphoma virus type I infection in nonendemic regions, tissue samples from six cases of large cell cutaneous T-cell lymphoma and four cases of small cell cutaneous T-cell lymphoma were screened for the presence of integrated proviral human T-cell leukemia/lymphoma virus type I DNA. Combined use of Southern blot hybridization and enzymatic DNA amplification revealed human T-cell leukemia/lymphoma virus type I-specific sequences in all cases of large cell cutaneous T-cell lymphoma and in none of the cases of small cell cutaneous T-cell lymphoma. These results suggest that in nonendemic areas, a significant proportion of large cell cutaneous T-cell lymphoma cases are associated with human T-cell leukemia/lymphoma virus type I.

Infection with the human T-lymphotropic virus type I. A review for clinicians

The human T-cell lymphotropic virus type I (HTLV-I) is the first retrovirus identified in humans. It has been responsible for a number of clinical syndromes, most notably adult T-cell leukemia or lymphoma and tropical spastic paraparesis. In the United States, infection with this virus is most frequently found in specific subsets of our population, particularly in those who live in the southeastern states, have southern Japanese ancestry, or share intravenous drug paraphernalia. Understanding the epidemiology and clinical manifestations of this virus is necessary to properly diagnose and care for patients with HTLV-I infection.

Adult T-cell leukemia-lymphoma

Adult T-cell leukemia-lymphoma, an aggressive T-cell leukemia, is characterized by the presence in the peripheral blood of malignant T cells that have highly indented or lobulated nuclei. Phenotypically the cells are usually helper T cells, but functionally they behave as suppressor cells. Patients have skin and lung involvement, hepatosplenomegaly, moderate lymphadenopathy sparing the mediastinum, and various metabolic abnormalities such as hypercalcemia. The clinical course may be chronic or acute, usually followed by a rapidly progressive terminal course. Adult T-cell leukemia-lymphoma is now known to be caused by human T-cell lymphotropic virus type I, which has been identified in the cells of patients with the disease.

Diffuse panbronchiolitis as a pulmonary complication in patients with adult T-cell leukemia

Forty-three cases of adult T-cell leukemia (ATL) admitted to our hospital between 1982 and 1987 were studied. Three of those were found to be complicated with diffuse panbronchiolitis (DPB). The incidence of DPB is considered to be significantly higher in patients with ATL. The three DPB-complicated cases composed one case each of the smoldering, chronic, and acute type of ATL. In each type, DPB preceded overt ATL and Candida albicans was found in sputa following detection for bacteria. The DPB complication apparently worsened the prognosis of the ATL patients. We have discussed a possible relationship between ATL and DPB.

Inhibition of the development of tumors or leukemia in mice and rats after reduction of food intake. Possible implications for humans

Recent data referring to the influence of a restricted diet on the incidence of radiation-induced tumors and leukemia in rats and mice are reviewed. The incidence of tumors developing in rats exposed to total-body gamma irradiation was reduced from 93% to 35% in female rats and from 59% to 7% in male rats after restriction of food intake. In a similar study carried out on mice, the incidence of leukemia in irradiated mice of both sexes was reduced from 50% to 4% after restriction of food intake. Radiation-induced leukemia in mice is caused by a transmissible virus activated by total-body gamma irradiation. In most of the animal species investigated thus far, tumors, leukemia, and lymphomas were found to be caused by transmissible viruses. It appears that activation of some of these latent viruses could be prevented by restriction of food intake. If the results of experiments carried out on mice and rats are extrapolated for humans, it would follow that all of us (particularly those who have had multiple cases of cancer or leukemia among family members) should aim at holding our weight below the limits considered normal for our age, sex, and height. This appears particularly important for persons that have been exposed to large doses of ionizing radiation.

Altered HLA antigens expressed on T and B lymphocytes of adult T-cell leukemia/lymphoma patients and their relatives

The HLA types of peripheral blood lymphocytes (PBL) of 36 adult T-cell leukemia/lymphoma (ATLL) patients were examined and compared with those of 45 healthy relatives of these patients, and with those of 10 non-ATLL families including 80 healthy members. Thirty-one percent of ATLL patients showed either a gain or a loss of HLA antigens determined by the presence of alien HLA antigens or the absence of inherent HLA antigens deduced from familial haplotype analysis. The antigen specificity of HLA gained or lost was variable and differed from case to case among ATLL patients. Although the gain of HLA was detected only in ATLL patients, the loss of HLA was found both in ATLL patients and in asymptomatic healthy relatives. The rate of HLA loss in ATLL patients (8.4%) and their relatives (17.8%) was much higher than in relatives of non-ATLL patients (1.1%). The HLA gain and loss revealed in the PBL of ATLL patients were confirmed by altered HLA phenotypes in the cloned T and B cells established from ATLL patients. Our results suggest that latently infecting HTLV-I may induce altered HLA phenotypes in T and B cells, primarily with loss of HLA antigens in a population of asymptomatic virus carriers, and secondarily with a gain of HLA antigens after the development of ATLL.

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

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

Does radiation-induced abrogation of skin Langerhans cell functions lead to enhanced incidence of skin tumors in patients with genetic disorders of DNA repair?

A hypothesis is presented which states that persons with the genetic disorders xeroderma pigmentosum and ataxia-telangiectasia, manifested by a deficiency of DNA repair, develop cutaneous tumors due to the elimination of reticuloendothelial system cells (Langerhans cells) in the skin, and the subsequent loss of control of epidermal cellular elements.

Infection of human T lymphotropic virus-I-specific immune T cell clones by human T lymphotropic virus-I

Human T lymphotropic virus-I (HTLV-I)-specific T cell lines were established and cloned. K5, an OKT8+ clone bearing multiple proviral integration sites, retained its HTLV-I-specific cytotoxicity and a normal dependence on interleukin 2 (IL-2), indicating that there is a finite number of transforming integration sites. R2, an OKT4+ HTLV-I-infected clone, initially mounted a proliferative response to HTLV-I; but then its IL-2-independent proliferation increased and the antigen specificity was lost. All HTLV-I-infected clones tested including K7, another OKT8+ transformed cytotoxic clone that had lost its reactivity, expressed comparable levels of T cell receptor beta-chain (TCR-beta) messenger (m)RNA. Although clones K5 and K7 had different functional properties, they had the same rearrangement of the TCR-beta gene, suggesting that they had the same clonal origin. These data indicate that HTLV-I-specific T cells retain their immune reactivity for variable periods of time following infection, but then usually lose it; in some cases, however, no alteration in function can be detected. The data also suggest that different consequences can take place in the same clone depending on the pattern of retroviral infection.

Occurrence of human T cell lymphotropic virus (type I) antibodies in cutaneous T cell lymphoma

Of 315 patients from Scandinavia and West Germany with cutaneous T cell lymphoma, thirty-six (11.4%) had specific antibodies reactive against human T cell lymphotropic virus type I (HTLV-I). Among the HTLV-I antibody-positive patients, one had Sézary syndrome; five, mycosis fungoides, plaque stage; sixteen, mycosis fungoides, plaque stage with nondiagnostic histologic features; and three, lymphomatoid papulosis. All the patients from the Copenhagen area had several samples taken during the course of their disease, but the HTLV-I antibody titer was unaltered independent of the clinical stage the individual patient had at the time of the study. Eighty-three patients with non-Hodgkin's lymphoma were tested for HTLV-I antibodies, and all except two showed negative results. The finding of specific antibodies reactive against HTLV-I in cutaneous T cell lymphoma suggests that a retrovirus related to HTLV-I plays an important role in the pathogenesis of cutaneous T cell lymphoma.

Healthy HTLV-I carriers in Japan: the haematological and immunological characteristics

The haematological and immunological characteristics of 34 healthy anti-HTLV-I antibody-positive individuals (HTLV-I carriers) in southwestern Japan were examined. No significant difference was noted between carriers and the controls in counts of RBC, WBC and the absolute number of lymphocytes. The serum IgG in the carriers was higher than that of the controls. The percentages of OKT4, OKT8, OKIa1 and B1-positive cells were found to be normal in the peripheral blood of the carriers, whereas the percentages of OKT11 and anti-Tac-positive cells were significantly higher in the carriers than in the controls. A correlation was observed between the percentages of anti-Tac-positive cells and the titres of anti-HTLV-I antibody in the carriers. After a 72 h incubation of peripheral blood lymphocytes with medium alone, the percentage of anti-Tac-positive cells tended to decrease in the controls, but to increase in carriers, with the appearance of large blastoid cells resembling blastic transformed lymphocytes cultured with mitogen. Tac and Ia antigens were markedly expressed on these large blastoid cells.

Serial transmission of human T-cell leukemia virus type I by blood transfusion in rabbits and its prevention by use of X-irradiated stored blood

Human T-cell leukemia virus type I (HTLV-I) was serially transmitted for 5 passages from rabbit to rabbit by blood transfusion. The virus could be transmitted with 20 ml of whole blood or washed blood cell suspension (fresh or stored for 1-2 weeks at 4 degrees C) but not with cell-free plasma from seroconverted rabbits. Seroconversion occurred 2-4 weeks after blood transfusion and serum anti-HTLV-I titers ranged from 1:20 to 1:640 with the immunofluorescence assay. From transfusion recipients of the 1st to 4th passages, virus-producing cell lines were established by culturing lymphocytes in the presence of T-cell growth factor (TCGF). Three of the 4 cell lines became TCGF-independent after 2-12 months of continuous culture. Blood was transfused between rabbits of opposite sexes and the recipient origin of each cell line was determined by chromosome analysis. We also investigated the effect of X-irradiation (6,000 rad) on blood from seropositive rabbits. Seroconversion likewise occurred in rabbits transfused with blood that had been irradiated immediately before transfusion but not in rabbits transfused with blood that had been irradiated and stored for 1-2 weeks at 4 degrees C. Thus, our rabbit model shows that HTLV-I is serially transmissible by blood transfusion and that this can be prevented by irradiation of blood. The same procedure, therefore, may be useful for the prevention of transfusion-related transmission of HTLV-I in humans.

Configuration and expression of the T cell receptor beta chain gene in human T-lymphotrophic virus I-infected cells

We studied the configuration and expression of the gene encoding the beta chain of the T cell receptor (TCR beta) in cell lines and primary tumor cells infected by the human T cell leukemia/lymphoma (lymphotrophic) virus type I (HTLV-I). Most of the cell lines and all the primary tumor cells showed rearrangement of the TCR beta gene, and in each case the rearrangement was distinct. The majority of cases examined were clonal with respect to a particular TCR beta gene rearrangement. Primary tumor cells from one case (SD) were found to have a tandem duplication of a portion of chromosome 7; this appears to have resulted in the presence of three alleles of the TCR beta gene, each of which is arranged differently. This suggests that the chromosomal abnormality, and possibly infection by HTLV-I, occurred before TCR beta gene rearrangement. Cell lines infected by HTLV-I express levels of TCR beta mRNA similar to PHA stimulated lymphocytes, suggesting that this gene is not transcriptionally activated as a result of infection by HTLV-I. Cloned T cells of known antigen specificity that are infected by HTLV-I in vitro show impairment of immune function, including loss of antigen-specific responsiveness and the acquisition of alloreactivity. Comparison of the configuration of the TCR beta gene before and after infection revealed no changes detectable by Southern blot analysis. Levels of expression of the TCR beta gene at the mRNA level and surface expression of the T3 complex were also not significantly altered, suggesting that changes in immune function cannot be attributed to quantitative changes in the TCR molecule. The configuration of the TCR beta gene in primary tumor cells infected by HTLV-I was compared with that in the derived cell lines. In all pairs examined, the configuration in the primary tumor cells was different from that in the cell lines, strongly suggesting that the cells that grow in culture are not the original neoplastic cells.

Host cell range of adult T-cell leukemia virus. I. Viral infectivity and binding to various cells as detected by flow cytometry

Adult T-cell leukemia virus is the member of a human type-C retrovirus family (HTLV) found to be associated with adult T-cell leukemia (ATL) in Japan. In our study, HTLV was isolated from the MT-2 cell line, purified on sucrose gradient and labelled with fluorescein-isothiocyanate (FITC-HTLV). The protein pattern of the virus was determined by SDS-gel electrophoresis and assured by Western blotting using ATL patient serum. Fresh human lymphocytes, separated B and T cells, mouse and rabbit lymphocytes, mouse fibroblasts, and 13 different tumor cell lines were tested in parallel for binding of FITC-HTLV and infectability by the virus. Virus binding to cell receptors was assayed by flow cytometry. Successful infection was monitored by following the expression of HTLV-determined antigen (HTLA). Most of the cells bound FITC-HTLV at levels ranging from 5% to 130% of the MT-2 cell binding. Only fresh human T, mouse and rabbit lymphocytes were infectable by cell-free virus preparations. The results demonstrate that HTLV receptors are present on different types of cells of both human and animal origin, and that infection by the virus is restricted to fewer host cells but not limited to a specific class of human lymphocytes.

Molecular and immunologic analysis of a chronic lymphocytic leukemia case with antibodies against human T-cell leukemia virus

The human T-cell leukemia virus type-I (HTLV-I) is a unique, exogenous, horizontally transmitted retrovirus which is T-cell tropic, and has been associated with a specific type of aggressive leukemia/lymphoma of mature T-cell origin. In a survey of lymphoid malignancies in Jamaica, antibodies to HTLV-I were also found in 6 of 17 patients with chronic lymphocytic leukemia (CLL), raising the possibility of an etiologic relationship. Further studies were undertaken on one of these patients to clarify the nature of the disease and possible virus relationship. Cell surface marker analysis of her peripheral blood cells documented that the majority of circulating lymphocytes were B-cells. DNA-cloned probe analysis with a complete HTLV-I proviral genome of these peripheral malignant B-cells, was negative for integrated virus. A T-cell line was established in culture from her peripheral blood. The presence of HTLV-I in the cultured T-cell line was established by the detection of expressed viral specific gag protein p-19 and proviral DNA. Thus, a B-cell lymphoid malignancy can occur in the presence of HTLV-I infected T-cells, suggesting the possibility of an indirect leukemogenic mechanism.

Isolation and characterization of a human T cell leukemia virus type II from a hemophilia-A patient with pancytopenia

Human T cell leukemia virus (HTLV) type I has been isolated from the cultured T cells of several patients with adult T cell leukemia (ATL) and has been etiologically linked to ATL. However, HTLV-type II has been isolated only once, from the T cells of a patient with a T cell variant of hairy-cell leukemia. We report here the isolation of HTLV-II-related virus from the cultured T cells of a hemophilia-A patient with pancytopenia. The T cell line (CM) grows in the absence of T cell growth factor. Cord blood T cells were rapidly transformed when co-cultivated with irradiated CM cells. Heterologous competition radioimmunoassays using purified HTLV-I p24 showed the expression of HTLV-IIMO-related protein in these cells. Electron microscopy of the CM cells showed the presence of intracellular and extracellular type C viral particles. Comparison of the proviral genome in the CM cell line and the prototype HTLV-IIMO-containing cell line (MO) by molecular hybridization with probes specific for HTLV-IIMO indicated that restriction cleavage sites were identical. The fresh peripheral blood leukocytes of the patient contained two complete copies of the proviral genome, despite the lack of HTLV-II p24 expression. The virus from the cell line CM is designated as HTLV-IICM to distinguish it from the original HTLV-IIMO isolate.

Occurrence of HTLV-I antibodies in Danish patients with cutaneous T-cell lymphoma

10 of 68 CTCL (cutaneous T-cell lymphoma) patients without features of ATLL had antibodies against HTLV-I (human T-cell leukaemia virus, type I). The titre of antibody in these positive patients was generally much lower than that seen in cases of ATLL (adult T-cell leukaemia/lymphoma); geometric mean of 80 for CTCL vs. 8000 for Caribbean ATLL. The presence of HTLV-I antibody was unrelated to clinical remission, relapse, or stages of the disease, and some positives were detected in the earliest phases of mycosis fungoides. Among controls and normal donors between the ages of 40 and 65, only 1 of 36 and 3 of 113, respectively, had low titre antibodies to HTLV-I in their sera. Only 5 of 354 Danish normal donors of all ages had antibody, which was identical to the rate in over 2000 US normal donors. In negative control experiments, these antibodies were unreactive with bovine leukaemia virus. These data suggest that HTLV-I or a related retrovirus crossreactive with HTLV-I occurs in a low percentage of the Danish population and patients with CTCL have such antibodies at an increased rate, but less than the rate seen for ATLL (greater than 90%).

Seroepidemiology of human T-lymphotropic retrovirus type I (HTLV-I) in residents of Niigata Prefecture, Japan. Comparative studies by indirect immunofluorescence microscopy and enzyme-linked immunosorbent assay

A large sample of carriers of human T-lymphotropic retrovirus type I (HTLV-I) in Niigata Prefecture was examined for the detection of natural antibodies to HTLV-I-related antigens in sera using both indirect immunofluorescence microscopy (IFM) and enzyme-linked immunosorbent assay (ELISA). The present findings are based on multiple surveys, using each assay technique at least twice. Although Niigata Prefecture has been considered a non-endemic region for HTLV-I, Sado Island has been proven by this study to be a relatively endemic pocket within this non-endemic area. Seropositivity was highest in residents of Sado Island; 97/1, 117 (8.7%) by IFM and 33/1,061 (3.1%) by ELISA; followed by Niigata City, 18/650 (2.8%) by IFM and 16/638 (2.5%) by ELISA; and lowest in the remaining areas, 57/2,631 (2.2%) by IFM and 20/2,551 (0.8%) by ELISA. Seropositivity was demonstrated in 172/4,398 (3.9%) by IFM and 69/4,250 (1.6%) by ELISA in Niigata Prefecture taken as a whole. In general, the incidence of seropositive residents increased gradually with age. The sex difference was not significant. The serum samples tested were categorized into 4 groups; (1) IFM and ELISA both positive, (2) IFM positive but ELISA negative, (3) IFM negative but ELISA positive, and (4) IFM and ELISA both negative. By absorption tests, IFM and ELISA seemed to recognize different specific antibodies in sera; IFM recognized antibodies to HTLV-I-related cellular antigens in addition to HTLV-I viral antigens, but ELISA recognized antibodies to HTLV-I viral antigens alone. Thus, IFM detected a broader spectrum of antigens, resulting in recognition of more positive sera than those detected by ELISA.

Functional and phenotypic studies of Japanese adult T cell leukemia cells

The cell surface marker profile and functional analysis of peripheral blood lymphocytes from 11 Japanese adult T cell leukemia patients were studied. The phenotypic analysis of Japanese adult T cell leukemia (ATL) cells by a series of 13 monoclonal antibodies showed that all ATL cells are anti-T4 reactive but some differ in their expression of T3, T11, and T12 antigens. Thus, considerable phenotypic heterogeneity exists in these populations of leukemia cells. When analyzed in functional assays, ATL cells were suppressive when added to a pokeweed mitogen- (PWM) driven Ig synthesis system. However, the suppression mechanism seemed to be more complex than originally conceived. ATL cells examined in this study seem to function mainly as an inducer of suppressor cells, and as such, activate normal T8 precursors of suppressor cells rather than function as suppressor effector cells. In addition, no evidence was obtained to suggest that suppression of PWM-stimulated IgG synthesis was mediated by natural killer (NK) activity of ATL cells. Rather, ATL cells seem to be markedly deficient in NK activity. These studies suggest that the majority of ATL cells tested are representative of and seem to be the leukemic counterparts of the T4+ suppressor inducer subset.

HTLV-III infection in brains of children and adults with AIDS encephalopathy

Unexplained debilitating dementia or encephalopathy occurs frequently in adults and children with the acquired immune deficiency syndrome (AIDS). Brains from 15 individuals with AIDS and encephalopathy were examined by Southern analysis and in situ hybridization for the presence of human T-cell leukemia (lymphotropic) virus type III (HTLV-III), the virus believed to be the causative agent of AIDS. HTLV-III DNA was detected in the brains of five patients, and viral-specific RNA was detected in four of these. In view of these findings and the recent demonstration of morphologic and genetic relatedness between HTLV-III and visna virus, a lentivirus that causes a chronic degenerative neurologic disease in sheep, HTLV-III should be evaluated further as a possible cause of AIDS encephalopathy.

Familial adult T-cell leukemia

Two siblings who developed adult T-cell leukemia (ATL) are presented. The patient and 7 of 26 healthy family members examined had the serum antibodies against ATL-associated antigens (ATLA). This family study shows that two main routes of transmission of human T-cell leukemia virus (HTLV) may be involved: one is the route from parents to children and the other is horizontal transmission among spouses, especially from husband to wife; the anti-ATLA-positive family is considered to be a high-risk group for ATL.

Presence of antibodies to human lymphoma-leukemia virus (HTLV-I) in Germans with symptoms of the acquired immunodeficiency syndrome (AIDS)

Sera from German patients exhibiting symptoms compatible with the acquired immune deficiency syndrome (AIDS) or the lymphadenopathy syndrome (LAS) were assayed for antibodies against human T-cell lymphoma/leukemia virus (HTLV-I)-related antigens by enzyme immunoassay, indirect immunofluorescence, and radioimmunoprecipitation. Antibodies against HTLV were detected in 3 out of 31 sera.

Molecular cloning of lymphadenopathy-associated virus

Lymphadenopathy-associated virus (LAV) is a human retrovirus first isolated from a homosexual patient with lymphadenopathy syndrome, frequently a prodrome or a benign form of acquired immune deficiency syndrome (AIDS). Other LAV isolates have subsequently been recovered from patients with AIDS or pre-AIDS and all available data are consistent with the virus being the causative agent of AIDS. The virus is propagated on activated T lymphocytes and has a tropism for the T-cell subset OKT4 (ref. 6), in which it induces a cytopathic effect. The major core protein of LAV is antigenically unrelated to other known retroviral antigens. LAV-like viruses have more recently been independently isolated from patients with AIDS and pre-AIDS. These viruses, called human T-cell leukaemia/lymphoma virus type III (HTLV-III) and AIDS-associated retrovirus (ARV), seem to have many characteristics in common with LAV and probably represent independent isolates of the LAV prototype. We have sought to characterize LAV by the molecular cloning of its genome. A cloned LAV complementary DNA was used to screen a library of recombinant phages constructed from the genomic DNA of LAV-infected T lymphocytes. Two families of clones were characterized which differ in a restriction site. The viral genome is longer than any other human retroviral genome (9.1-9.2 kilobases).

Reactivity of HTLV-transformed human T-cell lines to MHC class II antigens

T-cell lines established from individuals infected with human T-cell leukaemia virus (HTLV) or generated by co-cultivation of normal human T cells with HTLV-infected T-cells, express class II (HLA-D/DR or Ia) antigens of the major histocompatibility complex (MHC) and interleukin-2 (IL-2) receptors. Because the expression of these markers characterizes the differentiation of immunologically activated T cells, we have now explored the possibility that HTLV- infected T cells might be primed to autologous or allogeneic Ia antigens expressed by the infecting cells. Our studies on the capacity of HTLV-infected T cells to display responses on mixed lymphocyte culture indicate that such T cells as well as single-cell clones derived from them, react non-discriminatively to all known allelic variants of human HLA-D/DR antigens, including those expressed by the responding cells. This reaction is inhibited by antibody to human Ia and is not triggered by Ia-negative T-leukaemia cells. The structure recognized seems to be a common epitope determinant of human Ia antigens, as (HTLV-infected) T cells primed in vitro to one HLA-D/DR specificity display amplified responses to all other HLA-D/DR antigens. We therefore believe that autostimulation by a self-Ia determinant may trigger the clonal expansion of HTLV-infected T cells and potentiate autoimmune processes.

Antibodies to HTLV-I p24 in sera of blood donors, elderly people and patients with hemopoietic diseases in France and in French West Indies

Human T-cell lymphoma/leukemia virus type I (HTLV-I) is a type-C retrovirus originally isolated from patients with leukemia or lymphoma involving mature T lymphocytes. Epidemiological studies have shown that HTLV-I infection occurs not only in leukemic but also in normal people in at least two areas of the world: the Caribbean basin and the South-West of Japan. We report here the results of a large seroepidemiological study of HTLV-I infection in normal French blood donors, elderly subjects living in institutions and patients with various malignant hemopathies, obtained by the classical HTLV-I p24 radioimmunoassay. We were unable to demonstrate antibodies to HTLV-I in 510 sera from French volunteer blood donors born and living in continental France or in sera from 262 blood donors born in other countries (mainly in Europe and North Africa) and living in continental France at the time of collection. In contrast, among 131 sera from blood donors born in French overseas territories (French Guiana, French West Indies, and Reunion) but living at the time of collection in continental France, 2 (1.5%) were found to possess anti-HTLV-I antibodies. In a sample of 2,597 blood donors from Martinique, 39 (1.5%) were positive. A positive correlation with age was observed whereas no statistical relationship was found between HTLV-I antibodies and sex, red cell blood groups or the place of residence in Martinique. On the other hand, a very high level of positive values was observed in Martinique among old people living in institutions, 14% of those aged over 60 years being positive. HTLV-I-associated hematological malignancies have not been observed in patients born and living in continental France whereas a large number exist in the French West Indies. In the same area, the presence of anti-HTLV-I antibodies in 12% of patients with myeloma, a typical B-cell disease, merits attention.

Functional properties of antigen-specific T cells infected by human T-cell leukemia-lymphoma virus (HTLV-I)

Tetanus-toxoid specific helper-inducer T-cell clones, which had been infected and transformed by human T-cell leukemia-lymphoma virus (HTLV-I), were obtained from an antigen-specific human T cell line by using a limiting dilution technique in the presence of the virus. These HTLV-I-infected T-cell clones proliferated specifically in response to soluble tetanus toxoid but, unlike normal T cells, they could do so in the absence of accessory cells. The HTLV-I-infected T-cell clones did not present the antigen to autologous antigen-specific T cells that were not infected with HTLV-I. The capacity of helper-inducer T cells to retain antigen-specific reactivity after infection by HTLV-I, while losing the normal T-cell requirement for accessory cells, has clinical and theoretical implications.

Zoonotic diseases of cats

As veterinarians, our responsibilities do not end with the care of our patients. The welfare of our clients and their families depends on our ability to detect and control potentially zoonotic diseases in their pets. Because some of these zoonoses can have devastating effects on the development of the unborn fetus or on family health in general, discussion about these diseases between veterinarian and client is often emotionally charged. Under such circumstances, the offering of inaccurate and erroneous information by the veterinarian can have drastic consequences. It is likely that other zoonotic diseases of domestic pets will be identified in the future, especially those that can cause opportunistic infections in debilitated and immunodeficient persons. In the meantime, the potential hazards of cat ownership can be significantly reduced through an increased understanding of feline diseases and an improved level of health care for our feline patients.

Isolation of HTLV-transformed B-lymphocyte clone from a patient with HTLV-associated adult T-cell leukaemia

The human T-cell leukaemia/lymphoma virus (HTLV) is an exogenous retrovirus which has been associated with adult T-cell leukaemia/lymphoma (ATL). This malignancy of T lymphocytes is endemic to southern Japan, the West Indies, and to a lesser extent, the Middle East, Central Africa and the southeastern United States. ATL cells from patients of diverse geographical origins have been found to be infected with HTLV-1 (ref.6). HTLV is normally tropic for mature T lymphocytes, especially those expressing the helper-inducer surface antigen phenotype (OKT4 or Leu-3-positive), and the neoplastic T cells infected with HTLV generally express receptors for T-cell growth factor (detected by reactivity with anti-Tac antibody). However, we report here the isolation of a HTLV-infected B-lymphocyte clone from the peripheral blood of a patient with ATL. This clone is cytogenetically normal and is not infected with Epstein-Barr virus (EBV). Co-culture of cells from this clone with cord blood lymphocytes resulted in transmission of HTLV and the immortalization of either T or B lymphocytes. These results suggest that HTLV may be associated with a broader range of host cells than previously recognized.

Structure of 3' terminal region of type II human T lymphotropic virus: evidence for new coding region

The sequence of the 3' terminus of the human T lymphotropic virus type II (HTLV-II) was determined and compared to the corresponding sequence of HTLV-I. The 1557-nucleotide-long sequence can be divided into a 5' region that is not conserved between the two viruses, and a 3', 1011-nucleotide-long region that is highly conserved and that corresponds precisely with a long open reading frame for both HTLV-I and -II. The proteins that could be encoded by these open reading frames have a molecular weight of about 38,000 and are closely related in primary amino acid sequence. The genomic structure in the 3' region of HTLV was found to be similar to that of bovine leukemia virus.

Trans-acting transcriptional activation of the long terminal repeat of human T lymphotropic viruses in infected cells

The transcription initiation signals for retroviruses lie within the long terminal repeat (LTR) sequences that flank the integrated provirus. Two subtypes of human T lymphotropic virus (HTLV) are associated with different disease phenotypes. In this article it is shown that marked differences exist in the ability of LTR sequences of these subtypes to function as transcriptional elements in differentiated cell types. It is also shown that trans-acting regulatory factors present in HTLV-infected cells stimulate gene expression directed by these LTR sequences in a type-specific manner. These results have implications for understanding the diverse biological effects of HTLV infection.