Ethnic cluster of HTLV-I infection in Israel among the Mashhadi Jewish population

A high prevalence of human T-lymphotropic virus type I (HTLV-I) infection among Israeli Jews was previously reported. In the present study, screening for HTLV-I of Israeli Jews was expanded to 10 ethnic groups. HTLV-I antibodies were tested by the particle agglutination assay, ELISA, and by Western blot as a confirmatory method. The HTLV-I proviral genome was tested by nested PCR with tax primers (SK43/SK44 and Tr101/Tr102). The PCR tests were carried out in all seropositive subjects and the seronegative family members of the seropositives subjects in the Iranian population. Sixty-eight of the 1,679 subjects (4.1%) were found to be seropositive. The Jews originating from Mashhad had the highest infection rate of 60/306 (20%). Of the 479 Iranian non-Mashhadi Jews, 6 (1.3%) were seropositive. Of the 894 non-Iranian Israelis, only 2 (0.2%) were seropositive. HTLV-I proviral DNA was found in the peripheral blood lymphocytes of 66 out of 68 seropositive subjects and 6 out of 75 seronegative subjects. Sixty out of 123 (49%) Mashhadi Jews and 8 out of 14 (57%) non-Mashhadi Iranian Jews were PCR-positive. Three out of three seropositive non-Iranian Israelis were PCR positive. One non-Iranian Israeli (who originated from Ukraine) without family connections to the Iranian Jews was also PCR-positive. One hundred eighteen saliva samples (84 from subjects of Mashhadi origin, 31 from Iranian origin, and 4 of other origins) were also screened. Antibodies for HTLV-I were found in 23 out of 46 saliva samples from the individuals with particle agglutination (PA) and/or PCR-positive findings in blood. Twenty out of 23 PA-positive saliva samples also contained the proviral DNA. It is concluded that HTLV-I infection in Israel is mainly limited to Jews originating from Iran (most of them from Mashhad) and their family members. J. Med. Virol. 56:269–274, 1998. © 1998 Wiley-Liss, Inc.     

No evidence of HTLV-I proviral integration in lymphoproliferative disorders associated with cutaneous T-cell lymphoma.

Several recent studies have reported detection of HTLV-I genetic sequences in patients with cutaneous T-cell lymphoma (CTCL) including mycosis fungoides and Sezary syndrome. The purpose of this study was to determine whether HTLV-I was detectable in lesional tissues of patients suffering from diseases known to be associated with CTCL. Thirty-five cases were obtained from diverse geographical locations including Ohio, California, Switzerland, and Japan. Six of them had concurrent CTCL. Cases were analyzed using a combination of genomic polymerase chain reaction (PCR)/ Southern blot, dot blot, and Southern blot analyses. All assays were specific for HTLV-I provirus. Sensitivity ranged from approximately 10(-6) for PCR-based studies to 10(-2) for unamplified genomic blotting. Lesional DNA from patients with lymphomatoid papulosis (fourteen cases), Hodgkin's disease (twelve cases), and CD30+ large-cell lymphoma (nine cases) was tested for the HTLV-I proviral pX region using a genomic PCR assay followed by confirmatory Southern blot analysis with a nested oligonucleotide pX probe. All cases were uniformly negative. All of the Hodgkin's disease cases, eight of the large-cell lymphoma cases, and six of the lymphomatoid papulosis cases were then subjected to dot blot analysis of genomic DNA using a full-length HTLV-I proviral DNA probe that spans all regions of the HTLV-I genome. Again, all cases were negative. Finally, eleven of the Hodgkin's disease cases were also subjected to Southern blot analysis of EcoRI-digested genomic DNA using the same full-length HTLV-I probe. Once again, all cases were negative. These findings indicated that, despite utilization of a variety of sensitive and specific molecular biological methods, HTLV-I genetic sequences were not detectable in patients with CTCL-associated lymphoproliferative disorders. These results strongly suggest that the HTLV-I retrovirus is not involved in the pathogenesis of these diseases.     

Quantitation of HTLV-I proviral load by a TaqMan real-time PCR assay

A quantitative real-time PCR assay was developed to measure the proviral load of human T-lymphotropic virus type I (HTLV-I) in peripheral blood mononuclear cells (PBMCs). The HTLV-I copy number was referred to the actual amount of cellular DNA by means of the quantitation of the albumin gene. Ten copies of HTLV-I DNA could be detected with 100% sensitivity, and the assay had a wide range of at least 5 log(10). Intra- and inter-assay reproducibility was evaluated using independent extractions of PBMCs from an HTLV-I-infected patient (coefficients of variation, 24 and 7% respectively). The performance of this TaqMan PCR assay, coupled with its high throughput, thus allows reliable routine follow-up of HTLV-I proviral load in infected patients. Preliminary results using clinical samples indicate a higher proviral load in patients with HTLV-I-associated myelopathy/tropical spastic paraparesis than in asymptomatic carriers, and also suggest the usefulness of this quantitative measurement to assess the etiological link between HTLV-I and adult T-cell leukaemia/lymphoma-like syndromes.     

Detection of proviral human T-cell lymphotrophic virus type I DNA in mouthwash samples of HAM/TSP patients and HTLV-I carriers

Summary Human T-cell lymphotrophic virus type I (HTLV-I), is a member of the oncogenic retroviruses family endemic in several parts of the world and also recently identified in the Jewish Mashhadi population who immigrated from Iran to Israel. The virus is the causative agent of adult T-cell leukemia (ATL) and a chronic myelopathy known both as tropical spastic paraparesis (TSP) or HTLV-I associated myelopathy (HAM). The known modes of HTLV-I transmission are by sexual intercourse, from mother to child in breast milk, via blood transfusion, and by sharing of needles by parenteral drug users. In the present study we examined the presence of HTLV-I provirus genomic DNA by nested polymerase chain reaction (PCR) and by DNA hybridization in mouthwash samples obtained from 13 Mashhadi-born Iranian Jews with spastic paraparesis associated with HTLV-I, 4 Mashhadi-born Iranian Jews asymptomatic carriers for HTLV-I and 21 healthy controls. Proviral HTLV-I DNA was detected by mouthwash PCR in 12 of 17 HTLV-I infected subjects (71%) but in none of 21 controls. Proviral DNA was also detected in mouthwash samples using HTLV-I probe by dot blot hybridization assay. The presence of HTLV-I proviral DNA in whole saliva may suggest a possible transmission of the virus via saliva and explain the increased rate of infection in elderly Mashhadi-Jewish population.     

Graves' disease in HTLV-I carriers

Three carriers of human T-lymphotropic virus type I (HTLV-I) with Graves' disease are reported. All three cases were complicated with uveitis, and one also showed chronic arthropathy. Anti-HLTV-I antibody was found in the serum by the particle agglutination method and western blotting, and HTLV-I proviral DNA was detected in peripheral lymphocytes by the polymerase chain reaction and Southern blotting. HTLV-I is a causal agent of adult T-cell leukemia and HTLV-I associated myelopathy/tropical spastic paraparesis, and is believed to be related to the pathogenesis of diseases such as chronic arthropathy, uveitis, chronic bronchoalveolitis, and Sjögren's syndrome. On the other hand, retrovirus infection is considered to cause autoimmune diseases. Thus, the pathogenesis of Graves' disease in the present patients might be associated with HTLV-I infection.Abbreviations HTLV-I Human T-lymphotropic virus type I - ATL adult T-cell leukemia - HAM HTLV-I associated myelopathy - TSP Tropical spastic paraparesis     

Human T-lymphotropic virus type I (HTLV-I)-specific CD8+ cells accumulate in the lungs of patients infected with HTLV-I with pulmonary involvement

Pulmonary involvement has been identified in human T-lymphotropic virus type I (HTLV-I) carriers and patients with HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP). However, the relationship between HTLV-I infection and lung disease is poorly understood. The occurrence of HTLV-I-specific immune responses in the lungs of patients infected with HTLV-I with pulmonary involvement was investigated. The frequency of HTLV-I-specific CD8+ cells and the amount of HTLV-I proviral DNA were determined in bronchoalveolar lavage fluid cells and peripheral blood mononuclear cells (PBMCs) from five patients with HAM/TSP and one HTLV-I carrier who had pulmonary involvement. HTLV-I-specific CD8+ cells were detected by flow cytometry using human leukocyte antigen/antigen complex multimers. The analysis of bronchoalveolar lavage fluid revealed lymphocytosis in five of six patients. HTLV-I provirus was detected in the bronchoalveolar lavage fluid cells of all patients, and the proviral load in these cells was comparable to that in PBMCs. The frequency of HTLV-I-specific CD8+ cells in the bronchoalveolar lavage fluid cells was 5.1 times higher than that in PBMCs. Immunohistochemically, clusters formed by HTLV-I-specific CD8+ cells were detected in lung tissue by in situ tetramer staining. No samples were available from patients infected with HTLV-I without lung disorders. Whether accumulation of CD8+ cells is specific to patients with pulmonary involvement remains unclear. These results indicate that HTLV-I-specific CD8+ cells accumulate and HTLV-I-infected cells exist in the lungs of patients infected with HTLV-I with pulmonary involvement.     

Quantitation of HTLV-I and II proviral load using real-time quantitative PCR with SYBR Green chemistry.

BACKGROUND: Human T-lymphotropic virus type I (HTLV-I) is linked etiologically with adult T cell leukemia/lymphoma and HTLV-I-associated myelopathy/tropical spastic paraparsis (HAM/TSP). Human T-lymphotropic virus type II (HTLV-II) is associated with HAM/TSP and, in HIV coinfected patients only, rare cases of cutaneous T cell lymphoma. Proviral load may be important in the pathogenesis of HTLV-associated disease. MATERIALS AND METHODS: A real time quantitative PCR assay using SYBR Green intercalation was established. Primers targeting the tax region were standardized against MT2 and MOT cell line DNA for HTLV-I and HTLV-II, respectively. HTLV-I/II copy number was normalized to the amount of cellular DNA by quantitation of the HLA-DQ alpha gene. We measured proviral load in peripheral blood mononuclear cells (PBMCs) in a large cohort of 120 HTLV-I and 335 HTLV-II seropositive former blood donors. We also assessed the intra- and inter-assay reproducibility of the assay. RESULTS: Proviral load for HTLV-I infected patients ranged from 3.1 x 10(0) to 1.8 x 10(5)copies/10(6) PBMCs with a mean of 1.6 x 10(4) and a median of 3.0 x 10(3). HTLV-I was undetectable in 7 of 120 cases (5.8%). Proviral load for HTLV-II infected patients ranged from 1.1 x 10(0) to 1.0 x 10(6)copies/10(6) PBMCs with a mean of 2.8 x 10(4) and a median of 5.0 x 10(2). HTLV-II was undetectable in 31 out of 335 cases (9.3%). CONCLUSION: The assay has excellent dynamic range from 10(6) to 10(0)copies/reaction, good intra- and inter-assay reproducibility, and a lower limit of detection of a single copy per reaction. The sensitivity and high dynamic range allow determination of a broad range of HTLV-I/II proviral load in clinical subjects. This assay will facilitate the study of the relationship between proviral load and pathogenesis.     

Infection of peripheral blood mononuclear cells and cell lines by cell-free human T-cell lymphoma/leukemia virus type I.

Previous studies of in vitro infection by human T-cell lymphoma/leukemia virus type I (HTLV-I) have required cocultivation of target cells with HTLV-I cell lines or vesicular stomatitis virus pseudotypes containing HTLV-I envelope proteins. We report here the development of a cell-free infection assay for HTLV-I. Target cells were incubated with purified, DNase-treated HTLV-I virions for 4 h at 37 degrees C. Target cell DNA was then analyzed for the presence of newly synthesized HTLV-I proviral DNA by the highly sensitive polymerase chain reaction. Using this assay system, we have been able to consistently detect in vitro infection of a variety of cellular targets by different HTLV-I isolates. Optimal infection required the presence of 10 micrograms of DEAE-dextran per ml. The assay was dose dependent with respect to virus input. In general, the amount of proviral DNA detected correlated with the level of HTLV-I receptors present on the surface of the target cells, as measured by fluorochrome-labelled HTLV-I binding. Finally, the specificity of the assay was confirmed by demonstrating that the cell line, L1q, a somatic cell hybrid containing human chromosome 17q, to which the gene for the HTLV-I receptor has been mapped, was susceptible to infection by HTLV-I, while the parental mouse cell line from which it was derived, LMTK-, which lacks human chromosome 17q, was not.     

High frequencies of human T-lymphotropic virus type I (HTLV-I) infection and presence of HTLV-II proviral DNA in blood donors with anti-thyroid antibodies

To investigate the relationship between human T-lymphotropic virus (HTLV) types I and II and the pathogenesis of autoimmune thyroid diseases, we examined serum anti-thyroid antibodies in 1019 blood donors with or without serum anti-HTLV-I antibody as well as proviral DNA for HTLV-II in leukocyte DNA by the polymerase chain reaction in 395 blood donors with or without anti-thyroid antibodies. The frequency of donors with anti-HTLV-I antibody who also showed anti-thyroid antibodies (7.9%) tended to be higher than that (6.3%) among donors who did not have the anti-HTLV-I antibody. The frequency of anti-thyroid antibodies in 125 young male donors aged 16–39 years with anti-HTLV-I antibody (4.8%) was significantly higher (P<0.05) than that (0.6%) in 164 control donors without the antibody. In blood donors with anti-thyroid antibody, 25.0% of those with anti-HTLV-I antibody and 14.3% of those without the antibody had HTLV-II proviral DNA. In contrast, in donors without anti-thyroid antibody HTLV-II proviral DNA was detected in 2.3% of those with anti-HTLV-I antibody and in 0.6% of those without the anti body. Thus the detection rates in donors with anti-thyroid antibody were significantly higher (P<0.001) than those in donors without the antibody, regardless of HTLV-I infection. These results suggest that HTLV-I infection and the presence of HTLV-II proviral DNA may be independently related to the pathogenesis of autoimmune thyroid diseases.Abbreviations HTLV Human T-lymphotropic virus - PCR Polymerase chain reaction     

Search for human T-cell leukemia virus type I (HTLV-I) proviral sequences by polymerase chain reaction in the central nervous system tissue of HTLV-I-associated myelopathy

Summary Using the polymerase chain reaction (PCR), proviral DNA sequences of thepol andenv regions of human T-cell leukemia virus type I (HTLV-I) were directly amplified in paraffin-embedded and frozen tissue sections of active inflammatory central nervous system (CNS) lesions in three autopsy cases of HTLV-I-associated myelopathy (HAM) with serological confirmation. In parallel, the enumeration of UCHL-1 (monoclonal antibody reactive to T-cells) positive cells in the tissue sections subjected to PCR were carried out. Although the control DNA sequence of parathyroid hormone-like peptide gene was definitely amplified, no signals for HTLV-I proviral sequences were detected in these specimens. The number of UCHL-1 positive cell nuclei was almost on the border line of our PCR sensitivity in formalin-fixed tissue, which was estimated to be 20–200 copies. Therefore, it is unlikely that the central nervous system tissue damage in HAM/TSP is a consequence of productive infection of HTLV-I in the CNS tissue.     

Differential diagnosis of HTLV-I-associated myelopathy and multiple sclerosis in Iranian patients

Summary Two Iranian patients with chronic progressive spastic paraparesis and urinary dysfunction were referred to our hospital with the presumptive diagnosis of multiple sclerosis (MS). Routine CSF analysis and magnetic resonance imaging of the two patients were only partially characteristic of MS. Testing for antibodies to human T-cell leukemia virus type I [HTLV-1] in serum using a radioimmune precipitation assay revealed antibodies to HTLV-I in both patients. The infection with HTLV-I was confirmed by polymerase chain reaction (PCR) and liquid hybridization analysis using primers to the tax/rex region and a corresponding probe, demonstrating proviral DNA in peripheral blood mononuclear cells of both patients. On the basis of these findings demonstrating the presence of proviral HTLV-1 DNA in the two Iranian patients, the initial diagnosis of MS was corrected to that of HTLV-I-associated myelopathy (HAM). In contrast, several patients with definite MS (nine from Germany, two from Iran) with a relapsing and remitting form of the disease were tested for HTLV-1 infection by enzyme-linked immunosorbent assay and PCR, which yielded negative results. However, the mother of one HAM patient was found to be infected with HTLV-I. To support an association between HTLV-I infection and CNS disease in the two HAM patients, we analyzed the production of specific IgG antibodies within the CNS based on a simple enzyme immunoassay for viral IgG antibodies in CSF and serum. In the two HAM patients there was significant intrathecal antibody production directed against HTLV-I, but this was not found in any of the samples from MS patients. These findings demonstrate an immune reaction to HTLV-I in the CNS of HAM patients, thus confirming the association of infection and CNS disease. The demonstration of intrathecal HTLV-I antibody production also proved useful for the differential diagnosis of MS or HAM, especially in patients from areas endemic for HTLV-I.Abbreviations DTPA diethylenetriaminepentaacetic acid - ELISA enzyme-linked immunosorbent assay - HAM HTLV-I-associated myelopathy - HTLV-I human T-cell leukemia virus type I - MRI magnetic resonance imaging - MS multiple sclerosis - PBMC peripheral blood mononuclear cells - PCR polymerase chain reaction - RIPA radioimmune precipitation assay - SDS sodium dodecyl sulfate - TSP tropical spastic paraparesis     

Estimating the time of HTLV-I infection following mother-to-child transmission in a breast-feeding population in Jamaica.

Mother-to-child transmission of human T-cell lymphotropic virus type I (HTLV-I) is primarily due to prolonged breast-feeding (>6 months) in the postnatal period. Most infant infections are not identifiable until 12 to 18 months of age by available whole virus Western blot serologic tests because of their inability to distinguish passively transferred maternal antibody from infant antibody. We investigated two methods to assess more accurately the time of infant infection. In prospectively collected serial biospecimens, HTLV-I-specific immunoglobulin (Ig) isotypes of IgM and IgA were determined by Western blot and HTLV-I proviral DNA was detected by polymerase chain reaction (PCR). IgA and IgG reactivity was assessed in periodic serum samples from 16 HTLV-I-seropositive children while IgM reactivity was assessed in 9 of the 16 children. Approximately three to five samples were tested for each child. IgG reactivity was observed in 100% of children at 24 months of age and 73% of children at 6-12 months of age; however, this could represent maternal and not infant antibody. Both IgA and IgM reactivity were insensitive indicators of infection, with only 50% of children showing reactivity at 24 months of age. PCR testing was performed in biospecimens obtained from 11 of these children. An estimated median time of infection of 11.9 months was determined by PCR, which was similar to the median time to infection determined by whole virus Western blot (12.4 months; P = 0.72). PCR tests support a median time to infection that is similar to that estimated by whole virus Western blot.     

In situ hybridization detection of HTLV-I RNA in peripheral blood mononuclear cells of TSP/HAM patients and their spouses.

This is the first report of the direct detection of HTLV-I RNA in uncultured peripheral blood mononuclear cells (PBMNC's) of patients with tropical spastic paraparesis and HTLV-I-associated myelopathy (TSP/HAM) and their spouses, using the technique of in situ hybridization. Twenty-one Colombian patients were tested, all of whom had antibodies to HTLV-I; the presence of HTLV-I proviral DNA in their PBMNC's was confirmed by the polymerase chain reaction technique. Of the 21 patients 15 had a clinical diagnosis of tropical spastic paraparesis (TSP/HAM), 5 were asymptomatic relatives, and 1 patient had leukemia. In situ hybridization was positive in samples from 5 patients; 2 of these were TSP/HAM patients and the other 3 were healthy wives of TSP/HAM patients. This study demonstrates for the first time that viral RNA is expressed in uncultured PBMNC's of some patients with TSP/HAM in whom proviral DNA is also present; furthermore, the detection of HTLV-I RNA in the blood of female partners of TSP/HAM patients clearly illustrates the high likelihood of HTLV-I transmission through sexual contact.     

Infection without antibody response in mother-to-child transmission of HTLV-I in rabbits.

The presence or absence of the anti-human T-cell leukemia virus type (HTLV-I) antibody and the HTLV-I proviral genome was examined in the offspring of inbred rabbits, which were born to HTLV-I carrier does. The results showed that not all offspring born to the carriers were infected and that not all the infected offspring seroconverted at the age of 10 weeks, which is similar to observations made in human carriers. The anti-HTLV-I antibody was assayed by indirect immunofluorescence in 55 offspring at the age of 10 weeks, which were born to B/J or (B/J x Chbb:HM)F1 seropositive HTLV-I carrier does. Twelve out of 31 offspring born from F1 x F1 mating were seropositive, whereas none of 24 offspring born from B/J x B/J mating, F1 x B/J mating, or F1 x Chbb:HM mating were seropositive. The polymerase chain reaction (PCR) method revealed the presence of the HTLV-I proviral genome in 18 out of 23 offspring born from F1 x F1 mating (F2 hybrids). In these 18 HTLV-I-infected F2 hybrids, 8 were seropositive and 10 were seronegative. The major histocompatibility complex (MHC) of these 23 F2 hybrids was analyzed by restriction fragment length polymorphism (RFLP) in southern hybridization. The results showed no close correlation of MHC with HTLV-I susceptibility or with seroconversion. Natural infection via mother-to-child transmission of virus seems to produce seronegative as well as seropositive carriers. This rabbit model may be useful for the study of seronegative virus carriers via mother-to-child transmission of HTLV-I.     

In vivo fluctuation of HTLV-I and HTLV-II proviral load in patients receiving antiretroviral drugs

HTLV-I and HTLV-II infect T lymphocytes. A high HTLV-I proviral load in peripheral blood mononuclear cells (PBMCs) has been associated with a higher risk of neurologic disease. For HTLV-II, large numbers of infected lymphocytes might contribute to accelerate the immunodeficiency and increase the risk of neuropathy in HTLV-II/HIV-1 coinfected people. We have examined the impact of antiretroviral drugs on HTLV proviral load, testing longitudinal samples collected from 1 HTLV-I infected patient suffering HTLV-I-associated myelopathy (HAM), and two HTLV-II/ HIV-1 coinfected subjects. The HAM patient showed a reduction greater than 2 log in the peripheral proviral load after being treated with zidovudine and lamivudine. In contrast, potent antiretroviral treatment in HIV-1/HTLV-II coinfected carriers produced an initial increase in the HTLV proviral load, which was followed by a reduction greater than 1 log thereafter. In conclusion, antiretroviral drugs seem to reduce HTLV proviral load, although in HIV-1 coinfected persons a transient increase in HTLV proviral load could reflect the rapid blocking of HIV-1 replication occurring in response to therapy, thus causing an increase in the number of circulating T lymphocytes carrying HTLV proviral DNA.     

Differential diagnosis of HTLV-I and HTLV-II infections by restriction enzyme analysis of 'nested' PCR products.

A 'nested' polymerase chain reaction (PCR) assay is described which is capable of detecting single copies of human T-cell lymphotropic virus (HTLV) in genomic DNA extracted from peripheral blood mononuclear cells (PBMCs). A single set of 'nested' oligonucleotide primers, based on the highly conserved tax/rex region of the viral genome, was able to detect both HTLV-I and HTLV-II proviral sequences in clinical samples of diverse geographical origins, from the United States, Great Britain, Japan, the Caribbean, Italy, Greece, Iraq and West Africa. Rapid discrimination between HTLV-I and HTLV-II infections was achieved by restriction enzyme analysis of unpurified second-round PCR products, even in those cases in which serological assays had failed to provide a definitive result. Over a 2-year period, a total of 53 HTLV infections (37 HTLV-I and 16 HTLV-II) were identified by this technique and complete concordance with serological typing, available in 41 cases, was observed.     

Human T-lymphocyte virus type I (HTLV-I)-induced myeloneuropathy in rats: oligodendrocytes undergo apoptosis in the presence of HTLV-I

To investigate the pathogenetic role of human T-lymphocyte virus type I (HTLV-I) in central nervous system disease, a rat model for HTLV-I-associated myelopathy/tropical spastic paraparesis, designated as HAM rat disease, was examined with regard to chronological neuropathology, from early asymptomatic phase to late disease. In the thoracic spinal cord of rats with HTLV-I infection, the first event was the appearance of apoptosis of oligodendrocytes beginning at 7 months after induced infection, thereafter followed by the appearance of white matter degeneration, increase of macrophages/activated microglia and of gemistocytic astrocytes at 12, 15 and 20 months, respectively. In the spinal cord, HTLV-I provirus DNA was evident as early as 4 months after the infection, and HTLV-I pX and the tumor necrosis factor (TNF)-alpha messages began to be expressed at age 7 months, just before or at the same time as the appearance of apoptotic cells. Collective evidence suggests that the apoptotic death of oligodendrocytes, which may be induced either directly by the local expression of HTLV-I or indirectly by TNF-alpha, through the transactive function of p40Tax, is the major cause of chronic progressive myeloneuropathy in Wistar-King-Aptekman-Hokudai rats with HTLV-I infection.     

Differential susceptibility of human mononuclear cells to infection with HTLV-I

Infection with human T-cell leukaemia/lymphoma (HTLV-I) preferentially affects T cells of the OKT-4 phenotype. The aim of the present study was to determine whether distinct T-cell subsets exhibit differences in susceptibility to virus infection. T cells from peripheral blood were separated according to cell densities by 7-step Percoll gradients. Separated T-cell subpopulations were infected with HTLV-I, using cocultivation with irradiated virus producer MT-2 cell line. Percentages of HTLV-I-infected cells and their phenotypes were assayed by immunofluorescence assay (IFA), using highly specific mouse monoclonal antibody directed against HTLV-I P-19 core protein, and other surface markers. The results showed that different T-cell subpopulations were susceptible to HTLV-I infection with the exception of large granular lymphocytes (LGL) which exhibit high cell-mediated natural cytotoxicity (CMNC).     

HTLV-I/II infection in a high viral endemic area of Zaire,Central Africa: Comparative evaluation of serology,PCR, and significance of indeterminate Western blot pattern

The frequency of indeterminate Western blot (WB) seroreactivities against HTLV-I “gag encoded proteins” only, and the use of low specific diagnostic WB criteria led to the overestimation of HTLV-I seroprevalence in initial studies in intertropical Africa and Papua New Guinea. In order to clarify the meaning of such seroreactivity, 98 blood samples of individuals from a high HTLV-I endemic area in Zaire, Central Africa were studied by a WB assay containing HTLV-I disrupted virions enriched with a gp 21 recombinant protein and a synthetic peptide from the gp 46 region (MTA-1), and by the polymerase chain reaction (PCR) with 3 primers pairs and 4 different HTLV-I and or HTLV-II-specific probes. These 98 samples were taken mainly from patients with neurological diseases and from their relatives. Using stringent WB criteria, 28 sera (29%) were considered as HTLV-I-positive, 3 as negative and 67 (68%) as indeterminate. A large proportion of these indeterminate sera would have been considered as HTLV-I-positive samples according to previous low specific WB diagnostic criteria. After PCR, 35 samples (36%) were considered as positive for the presence of HTLV-I proviral DNA. Out of the 67 WB seroindeterminate, 10 (15%) were found HTLV-I-positive by PCR. These 10 individuals exhibited in WB multiple band reactivity with p19 and/or p24 (7 cases of both) associated in 6 cases with rgp 21, but never with MTA-1. No samples were found PCR-positive for HTLV-II despite the findings of 11 sera suggestive of HTLV-II by WB. These findings demonstrate that even in a high HTLV-I endemic area, only a minority (about 15%) of the WB-seroinde-terminate individuals could be considered as infected by HTLV-I, and that very stringent WB criteria could lead to overlooking some infected individuals. © 1994 Wiley-Liss, Inc.     

No evidence of HTLV-I infection in French patients with multiple sclerosis using the polymerase chain reaction.

The polymerase chain reaction (PCR), using three primer pairs in the pol, tax, and env regions of the HTLV-I genome, was unable to detect HTLV-I in the blood samples of 54 caucasian subjects with multiple sclerosis who were seronegative for HTLV-I/II. Seventeen HTLV-I/II seropositive (by ELISA and Western blot) subjects used as positive controls were positive with the three primer pairs. The PCR was negative in 47 healthy HTLV-I/II seronegative (by ELISA) subjects at low risk of HTLV-I infection used as negative controls. These results suggest that there is no association between the occurrence of HTLV-I sequences and the development of multiple sclerosis.