Human T lymphotropic virus types I and II proviral sequences in Argentinian blood donors with indeterminate Western blot patterns

Human T-cell lymphotropic virus (HTLV) seroindeterminate blood donors have been reported worldwide including Argentina. To investigate the significance of HTLV-I/II seroindeterminate Western blot (WB) patterns, we conducted an 8-year cross-sectional study. Of 86,238 Argentinian blood donors, 146 sera were reactive by screening tests. The WB results indicated that 20% were HTLV-I reactive, 8% HTLV-II reactive, 61% indeterminate, and 11% negative. The overall seroprevalence was 0.034% for HTLV-I, 0.014% for HTLV-II, and 0.103% for indeterminate. In 57 reactive specimens, HTLV-I/II provirus could be examined by type specific PCR for tax, pol, and env regions. When at least two gene fragments were amplified HTLV-I/II infection was considered confirmed. PCR results confirmed all WB seropositive samples for HTLV-I (n = 15), and HTLV-II (n = 7), and the only WB negative case was also PCR negative, showing a complete concordance between PCR and WB. However, of 34 WB seroindeterminate sera studied by PCR, in 5 was proviral DNA amplified. According to our criteria PCR confirmed one to be HTLV-I, and one HTLV-II, 3 remained indeterminate since only tax sequences were amplified. Among WB indeterminate samples tested by PCR, most of their serological profile showed reactivity to gag codified proteins but lacked env reactivities (70%). One sample with a WB gag pattern showed proviral tax sequences, but of the four samples with reactivity to env proteins GD21 (n = 3) or rgp46II (n = 1) PCR results indicated that one was HTLV-I, one was HTLV-II, and two were indeterminate (only tax sequences). In conclusion, the majority of HTLV-seroindeterminate WB donors exhibited a gag indeterminate profile lacking HTLV provirus, and were thus considered uninfected. However, seroreactivity to env proteins, in particular to GD21, may indicate infection and a follow-up study of each seroreactive blood donor should be considered.     

Evaluation of a new, fully automated immunoassay for detection of HTLV-I and HTLV-II antibodies

Screening blood donations for human T-lymphotropic virus types I and II (HTLV-I/II) continues to be important in protecting the safety of blood products and controlling the global spread of these retroviruses. We have developed a fully automated, third generation chemiluminescent immunoassay, ARCHITECT rHTLV-I/II, for detection of antibodies to HTLV-I/II. The assay utilizes recombinant proteins and synthetic peptides and is configured in a double antigen sandwich assay format. Specificity of the assay was 99.98% (9,254/9,256, 95% CI = 99.92-100%) with the negative specimens from the general population including blood donors, hospital patients and pregnant women from the US, Japan and Nicaragua. The assay demonstrated 100% sensitivity by detecting 498 specimens from individuals infected with HTLV-I (n = 385) and HTLV-II (n = 113). ARCHITECT rHTLV-I/II results were in complete agreement with the Murex HTLV-I/II reference assay and 99.7% agreement with the Genelabs HTLV Blot 2.4 confirmatory assay. Analytical sensitivity of the assay was equivalent to Murex HTLV-I/II assay based on end point dilutions. Furthermore, using a panel of 397 specimens from Japan, the ARCHITECT rHTLV-I/II assay exhibited distinct discrimination between the antibody negative (Delta Value = -7.6) and positive (Delta Value = 7.6) populations. Based on the excellent specificity and sensitivity, the new ARCHITECT rHTLV-I/II assay should be an effective test for the diagnosis of HTLV-I/II infection and also for blood donor screening.     

Concomitant augmentation of CD4+ CD29+ helper inducer and diminution of CD4+ CD45RA+ suppressor inducer subset in patients infected with human T cell lymphotropic virus types I or II.

To examine the immunomodulatory effects of HTLV infection, lymphocyte subset analysis was performed on patients infected with human T cell lymphotropic virus type-I (HTLV-I, n = 6) or -II (HTLV-II, n = 12) and on normal blood donors (n = 16). The percentages of total B lymphocytes (CD19), natural killer (NK) cells (CD16), T lymphocytes and their subsets (CD2, CD3, CD4, CD5, CD7, CD8), and IL-2R (CD25) were found to be within the range found in normal donors. However, the expression of CD8+ HLA-DR+ increased significantly in patients with HTLV-I or HTLV-II infection (14.1 +/- 3.9% and 9.7 +/- 2.4% respectively; P less than 0.01) when compared with controls (3.2 +/- 1.1%). In addition, there was a significantly greater proportion of CD4+CD29+ T lymphocytes (29.3 +/- 6.1% and 31.1 +/- 9.0%; P less than 0.05) with concomitant diminution of CD4+CD45RA+ T lymphocytes (8.3 +/- 3.3% and 11.4 +/- 1.5%; P less than 0.01) in patients infected with HTLV-I or HTLV-II respectively, when compared with controls. The increased percentage of CD4+CD29+ subpopulations showed a direct correlation (rs = 0.86; P less than 0.001) with HTLV-specific antibody production. No difference in the CD8 population coexpressing CD29 and S6F1 (an epitope of LFA-1) were observed in the HTLV-infected group when compared with normal donors and functional analysis exhibited minimal cytotoxicity against lectin labelled heterologous target cells. Thus, the shift in the suppressor/cytotoxic to helper/inducer 'memory' CD4+ may be associated with immunoregulatory abnormalities often found in persons infected with HTLV-I or HTLV-II.     

Human T-cell leukemia/lymphoma viruses. Life cycle, pathogenicity, epidemiology, and diagnosis.

Human T-cell leukemia/lymphoma virus type I (HTLV-I) was discovered in 1980, and it subsequently was found to be the cause of adult T-cell leukemia/lymphoma. A progressive neurologic disease known as tropical spastic paraparesis, or HTLV-I-associated myelopathy, has also been linked to infection with HTLV-I. A related virus, HTLV type II (HTLV-II), has been isolated from patients with hairy-cell leukemia, but it has not been proved to be the cause of any disease. In late 1988, US blood banks began screening all blood donations for antibodies to HTLV-I/II. This program has resulted in the identification of many unexpectedly seropositive blood donors and provided much information about the prevalence of HTLV-I/II in the United States. In this article, I review the replication of these agents, as well as their pathogenesis, diagnosis, and mechanisms of spread.     

Development of a supersensitive polymerase chain reaction method for human T lymphotropic virus type II (HTLV-II) and detection of HTLV-II proviral DNA from blood donors in Japan

A supersensitive polymerase chain reaction procedure was developed to detect human T-lymphotropic virus type II (HTLV-II) proviral genome. Six primer pairs covering the various regions of HTLV-II were compared and selected on the basis of specificity and sensitivity. Among them, one primer pair of the pol region of HTLV-II (II pol) was able to amplify and detect even 0.1 fg of the cloned plasmid HTLV-II DNA (seven copies) by regular ethidium bromide staining on polyacrylamide gel. By using this procedure, we screened 189 HTLV-I seropositive blood donors from Yamaguchi and Fukuoka Red Cross Blood Centers, Japan. There were four positive samples detectable with the HTLV-II-specific pol primer pair, as well as with the HTLV-I tax primer pair. The amplified DNAs of two specimens were cloned and sequenced. The sequences of the HTLV-I tax region from both specimens were identical to that of HTLV-I. On the other hand, those of the HTLV-II pol region were identical to that of HTLV-II, except for one base substitution in a clone from one subject. These results indicate that dual infection of HTLV-I and HTLV-II in the same persons occurs among Japanese blood donors.     

The seroepidemiology of human T-lymphotropic viruses: types I and II in Europe: a prospective study of pregnant women

BACKGROUND: Up to 20 million persons are infected with the human retroviruses human T-lymphotropic virus (HTLV)-I and HTLV-II globally. Most data on the seroprevalence of HTLV-I and HTLV-II in Europe are from studies of low-risk blood donors or high-risk injection drug users (IDUs). Little is known about the general population. METHODS: A prospective anonymous study of HTLV-I and HTLV-II seroprevalence among 234,078 pregnant women in Belgium, France, Germany, Italy, Portugal, Spain, and the United Kingdom was conducted. Maternal antibody status was determined by standard methods using sera obtained for routine antenatal infection screens or eluted from infant heel prick dried blood spots obtained for routine neonatal metabolic screens. RESULTS: Anti-HTLV-I/II antibodies were detected and confirmed in 96 pregnant women (4.4 per 10,000, 95% confidence interval [CI]: 3.5-5.2). Of these, 73 were anti-HTLV-I, 17 were anti-HTLV-II, and 6 were specifically anti-HTLV but untyped. The seroprevalence ranged from 0.7 per 10,000 in Germany to 11.5 per 10,000 in France. CONCLUSIONS: Pregnant women better reflect the general population than blood donors or IDUs. The seroprevalence of HTLV-I and HTLV-II in Western Europe is 6-fold higher among pregnant women (4.4 per 10,000) than among blood donors (0.07 per 10,000). These data provide a robust baseline against which changes in HTLV-I and HTLV-II seroprevalence in Europe can be measured.     

Human T-cell lymphotropic virus types I and II (HTLV-I and -II) infection among seroindeterminate cases in Argentina

Human T-cell lymphotropic virus (HTLV) seroindeterminate cases have been reported among blood donors (BD) and in at-risk populations worldwide, including Argentina. The objective of the present work was to study the presence of HTLV-I/II infection and its association to specific Western blot (WB) patterns among healthy BD and at-risk populations in Argentina. We analyzed 83 HTLV-I/II seroindeterminate WB cases diagnosed among BD (n = 49) and in different at-risk populations (n = 34) for human retroviruses infections. Multiple indeterminate WB patterns were observed. Out of the total, 13.2% (11/83) of the cases were found to be HTLV-I/II positive by nested-PCR (n-PCR), including 13.2% (11/83) HTLV-I and 2.4% (2/83) presenting HTLV-I and -II co-infection. Most of their serological profiles showed reactivity to gag or env codified proteins. Two samples amplified only one of the six analyzed genes (1 HTLV-I pol gene and 1 HTLV-II tax gene). There was no association between the presence of Trypanosoma cruzi infection and an HTLV-I/II indeterminate WB pattern (only 3 of the 83 samples were positive for T. cruzi antibodies). In conclusion, the majority of HTLV-seroindeterminate WB donors lacked HTLV provirus and was thus considered uninfected. However, when seroreactivity to Env and Gag proteins are observed on the WB and especially in at-risk populations, HTLV infection should be suspected; such individuals should be followed-up and retested.     

Seroepidemiology of HTLV-I/II in Argentina: an overview

In this report, the results of seroepidemiologic studies of human T-lymphotropic virus type I (HTLV-I) and type II (HTLV-II) infections in different population groups in Argentina have been compiled. The studies have shown a high prevalence of HTLV-I/II infection in blood donors in the provinces in the north of Argentina (1.0% in Jujuy, 0.7% in Salta, and 0.6% in Formosa) and a low prevalence in the provinces in the central region of the country (相似文献   

Infection with human T lymphotropic virus type I in organ transplant donors and recipients in Spain

Human T-cell lymphotropic virus (HTLV) antibody screening is not recommended uniformly before transplantation in Western countries. In the year 2001, the first cases of HTLV-I infection acquired through organ transplantation from one asymptomatic carrier were reported in Europe. All three organ recipients developed a subacute myelopathy shortly after transplantation. This report rose the question about whether to implement universal anti-HTLV screening of all organ donors or selective screening of donors from endemic areas for HTLV-I infection should be carried out. A national survey was conducted thereafter in which anti-HTLV antibodies were tested in 1,298 organ transplant donors and 493 potential recipients. None was seropositive for HTLV-I and only one recipient, a former intravenous (i.v.) drug user, was found to be infected with HTLV-II. In a different survey, HTLV screening was conducted in 1,079 immigrants and 5 (0.5%) were found to be asymptomatic HTLV-I carriers. All came from endemic areas for HTLV-I infection. No cases of HTLV-II infection were found among immigrants. These results support the current policy of mandatory testing of anti-HTLV antibodies in Spain only among organ transplant donors coming from HTLV-I endemic areas or with a highly suspicion of HTLV-I infection.     

Decreasing trends in HTLV‐1/2 but stable HIV‐1 infection among replacement donors in Argentina

In Argentina, current procedures to ensure safety of the blood supply for transfusion include reviewing the records of blood donors with particular attention to the serologic detection of specific blood borne infections. Data of 28,483 blood donations received from January 1, 2003 to December 31, 2008 in a public hospital in Buenos Aires were analyzed. Of the 28,483 blood donations, 7,442 (26.1%) were female donors, 14,582 (51.2%) were younger than 35 years old, and 23,746 (83.4%) were Argentine. Among all, only 285 (1.0%) were voluntary donations. The prevalence of HTLV‐1/2 was 0.1% (95% CI 0.063–0.15), being 0.07% for HTLV‐1 and 0.03% for HTLV‐2. The prevalence of HIV‐1 was 0.2% (95% CI 0.110–0.206). No HIV‐1/HTLV‐1/2 co‐infections were detected among volunteer donors. During this study period, data confirm that HTLV‐1/2 infection was not endemic in Buenos Aires, and that the prevalence of HTLV‐1/2 decreased throughout while HIV‐1 was stable. Due to the small number of voluntary donations, we could not conduct comparisons to infection rates in replacement donations. Although there have been several ongoing programs aimed at recruiting voluntary blood donations and changing from mostly replacement donations to an altruistic system of blood donations, Argentina is still far from reaching this objective. Additional efforts are needed in order to increase and assure the quality of blood supply in this country. J. Med. Virol. 82: 873–877, 2010. © 2010 Wiley‐Liss, Inc.     

Hematological indices in a cohort of HTLV-I/II and HIV-1 infected intravenous drug users in New York City

The prevalence and clinical consequences of human T-cell lymphotropic viruses types I and II (HTLV-I/II) infection in human immunodeficiency virus-1 (HIV-1) infected persons are areas of continuing interest. This article reports the preliminary findings of the hematological indices in 454 patients infected with HIV-1 and HTLV-I/HTLV-II. Based on serology, 46.2% of the patients had evidence of HIV-1 infection only, 4.6% had evidence of HTLV-I/II only, 14.3% had evidence of both HIV-1 and HTLV-I/II, and 34.8% had evidence of neither HIV-1 or HTLV-I/II. The patient group with both HTLV-I/II and HIV-1 infection had lower total white blood cell, platelet, and serum hematocrits than patients with either HIV-1 or HTLV-I/II infection. While these differences were insignificant, they do not suggest any HTLV-I/II-induced protective effect against HIV-1 related hematological consequences.     

Is seroprevalence of HTLV-I/II among blood donors in India relevant?

Human T-cell lymphotropic virus type I/II (HTLV-I/II) is associated with certain hematologic and neurologic disorders. Seroprevalence studies demonstrate that the distribution of HTLV-I/II is heterogeneous worldwide and not specific to one region. Because blood is one of the major routes of transmission of the virus, blood banks of several countries routinely screen all blood donations for HTLV-I/II. The aim of the present study was to assess the seroprevalence rate of HTLV-I/II antibodies among Indian blood donors and to confirm the positive rates by polymerase chain reaction (PCR). Between Jan 2004 to May 2005, consecutive blood samples of 10,000 blood donors were collected at the blood bank of Armed Forces Medical College, Pune. The samples were screened for HTLV-I/II by enzyme-linked immunosorbent assay (ELISA) method. Screening resulted in 18 (0.18%) positive samples, of which 14 (77.8%) samples were also positive by PCR. The prevalence of HTLV-I/II carriers in India seems to be negligible and is not a major public health hazard. Hence, routine screening of Indian blood donors for antibody to HTLV-I/II is not warranted due to its low prevalence in India.     

Use of a generic polymerase chain reaction assay detecting human T-lymphotropic virus (HTLV) types I,II and divergent simian strains in the evaluation of individuals with indeterminate HTLV serology

In countries with a low prevalence of human T-lymphotropic virus (HTLV) infection, indeterminate HTLV serologies are a major problem in blood bank screening because of the uncertainties about infection in these cases. The recent discovery of two new types of simian T-lymphotropic virus (STLV), which give an HTLV-indeterminate serology, raises the question whether indeterminate serologies in humans may be linked to new types of HTLV. Starting from a Tax sequence alignment of all available primate T-cell lymphotropic virus strains (PTLV), including the two new types STLV-PH969 and STLV-PP1664, we developed generic and type-specific nested polymerase chain reactions (PCRs). The generic PCR proved to be highly sensitive and cross-reactive for all four types of PTLV, while the discriminatory PCRs had a high sensitivity and a specificity of 100%. There was no cross-reactivity with human immunodeficiency virus (HIV), ensuring correct interpretation of results from coinfected patients. Among the 77 serologically indeterminate samples tested, 6 were found to be HTLV-IPCR positive and 1 was HTLV-II PCR positive. Sequencing of one of the HTLV-I PCR positives excluded PCR contamination, and revealed a divergent type of HTLV-I. The majority of the seroindeterminate samples (91%) were however HTLV-PCR negative, and no new types of HTLV were found. This new assay can identify otherwise undetected HTLV-I or HTLV-II infections and is a useful tool of screening for new types of HTLV among seroindeterminate samples. J. Med. Virol. 52:1–7, 1997.© 1997 Wiley-Liss, Inc.     

False positive antibody results against human T-cell lymphotropic virus in patients with severe acute respiratory syndrome

Taiwan suffered from the outbreak of severe acute respiratory syndrome (SARS) in 2003. Our laboratory performed a series of virology and serology tests for SARS patients admitted to our hospital. Cross-reactivity was found when testing for antibody against human T-cell lymphotropic virus (HTLV) in one patient with SARS. Therefore, antibodies against HTLV were examined in paired-sera from 26 SARS patients. ELISA and a neutralization test were used to measure anti-SARS antibodies. Seroconversion for antibody against SARS-CoV was observed in all patients. Surprisingly, with the use of ELISA for HTLV, sera for 13 patients were positive for HTLV (50%), and seroconversion for HTLV was also observed in 10 patients (38.5%). Western blot for HTLV on those 26 paired-sera from 13 HTLV-positive patients displayed 5 positive results for HTLV-I, 7 positive results for HTLV-II, 1 positive result for both HTLV-I and II, 9 negative results for either HTLV-I or HTLV-II, and 4 "indeterminate" results. The findings that antibody to HTLV can be detected in blood samples collected from SARS patients provide important information for safe handling of blood products. Without such knowledge, blood products can be discarded mistakenly even though they contain anti-SARS-CoV antibodies that may be potentially valuable for SARS therapy.     

Human T-cell lymphotropic virus types I and II infections in patients with leukaemia/lymphoma and in subjects with sexually transmitted diseases in Nigeria

Summary Serological assays that distinguish antibodies to human T-cell lymphotropic virus types I (HTLV-I) and type II (HTLV-II), and polymerase chain reaction (PCR) tests were used to investigate association of these two human retroviruses with several well-defined clinical conditions in Nigeria. We compared the frequency of HTLV-I and HTLV-II infections among patients with lymphoproliferative disorders (n=65), individuals with various sexually transmitted diseases (n=40), patients with genital candidiasis (n=25) and apparently healthy individuals (n=60). Serological analysis of blood samples from all four groups showed that 10 of the 190 (5.3%) individuals tested were confirmed positive for the presence of antibodies to HTLV-I (6) or HTLV-II (4). Using the PCR technique, specific HTLV-I or HTLV-II sequences were amplified from the genomic DNA of 4 of 6 HTLV-I seropositive and 3 of the 4 HTLV-II seropositive individuals respectively. However, sequences of both viruses were amplified from the genomic DNAs of the remaining 3 seropositive individuals. Since one of the 5 sets of primer pairs [(SK110 (II)/SK III (II)], which is used for specific identification of HTLV-II did not amplify the target sequence from the genomic DNAs of any of the 4 HTLV-II-confirmed seropositive individuals in this study, it suggested sequence diversity of these viruses in Nigeria. The virus-infected individuals identified in this study were one (1.5%) of the 65 patients with leukaemia/lymphoma (HTLV-I), 6 of 40 (15.0%) individuals (HTLV-I=1, HTLV-II=3, HTLV-I/II=2) with sexually transmitted diseases (STD), one of 25(4.0%) subjects with genital candidiasis for HTLV-I, and 2 of 60 (33.3%) healthy individuals (one for HTLV-I and one for HTLV-I/II). There was a significant difference (P<0.025) between the prevalence of HTLV-I/II infections among patients with lymphoma/leukaemia and those who attended STD clinic in Ibadan, Nigeria. This study also suggests that while HTLV-I and HTLV-II may be important sexually transmitted viruses, they may not be specific aetiological agents of the common lymphoproliferative disorders in Nigeria.     

Primary isolation of human T-cell leukemia-lymphoma virus types I and II: use for confirming infection in seroindeterminate blood donors.

We describe the use of an immunofluorescence assay and coculture to confirm human T-cell leukemia-lymphoma virus (HTLV) infection. Peripheral blood mononuclear cells from 32 of 32 seropositive donors were positive in the immunofluorescence assay, and 63% of their cocultures produced p24 antigen. Specific antibodies distinguished HTLV type I (HTLV-I) from HTLV-II. HTLV-I or HTLV-II was isolated from donors with indeterminate serologic test results.     

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     

Human T-cell lymphotropic virus in a population of pregnant women and commercial sex workers in South Western Nigeria

Background: Over 20 million persons are infected with HTLV-I/II globally. The virus is endemic in Africa and it is also transmitted sexually. Continued identification of high risk groups is important for the control of the disease. Objectives: To determine the prevalence of HTLV infection amongst two highly sexually active groups, pregnant women and CSWs in South Western Nigeria. Methods: Serum samples were tested for the presence of HTLV-I/II antibodies using the Vironostika((R)) HTLV-I/II micro ELISA system. Results: A total of 364 serum samples collected from pregnant women, commercial sex worker (CSW) and secondary school students (control group) from Ibadan. While only 4 (5.1%) of 78 secondary school students (average age: 13years) were reactive for HTLV infection, 20 (16.7%) of 120 pregnant women (average age: 26years) and 38 (22.9%) of 166 CSWs (average age: 23years) were found to have antibodies against HTLV in their sera. The results of this study thus show that HTLV infection is active in the population although higher in pregnant women (although not statistically significant) and CSWs (p>0.05). Pregnant women and CSWs are therefore at a higher risk of HTLV transmission than other members of the population. Conclusion: Routine screening for HTLV infection may go a long way to understanding the epidemiology of HTLV infection in Nigeria and subsequently provide tools for its prevention and control.     

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.     

Serological speciation of human T-cell leukaemia virus infections using synthetic peptide antigens

In order to assess the specificity and sensitivity of two peptide-based assays (Synth^TM HTLV-I and HTLV-II enzyme-linked immunoassay [EIA] [UBI] and Select-HTLV^TM EIA [IAF]) in discriminating between antibody to HTLV-I and HTLV-II infection, a panel of 186 well-characterised serum/plasma samples was tested by the two assays. The panel comprised 160 samples that by Western blot were confirmed to contain antibodies to HTLV-I/II and 26 samples that showed reactivity with gag but not env gene products. Both assays were found to be specific in that they did not misclassify any of the 80 specimens from cases of tropical spastic paraparesis or adult T-cell leukaemia/lymphoma, diseases believed to be HTLV-I associated, as anti-HTLV-II positive. Of the 160 specimens confirmed as anti-HTLV-I/II positive by Western blot, 6.2% were negative or untypable in the Synth EIA compared with 13.7% in the Select EIA. Of the 26 Western blot indeterminate samples, 16 were negative by both assays. Five were typed as anti-HTLV-I by both assays and 5 as anti HTLV-II by Select EIA only. The peptide based EIAs offer an economical and, in most cases, reliable means of discriminating between anti-HTLV-I and anti-HTLV-II. However, they should only be applied to sera that have been confirmed by Western blot or other methods as anti-HTLV-I/II positive. Even then they may fail to speciate sera from non-Japanese, non-Afrocaribbean populations. © 1993 Wiley-Liss, Inc.