Human T-cell leukemia virus type 1 may invalidate T-SPOT.TB assay results in rheumatoid arthritis patients: A retrospective case-control observational study

Background

CD4-positive T cells are the main target of human T-cell leukemia virus type 1 (HTLV-1). Interferon-γ release assays rely on the fact that T-lymphocytes release this cytokine when exposed to tuberculosis-specific antigens and are useful in testing for latent tuberculosis infection before initiating biologic therapy, such as anti-tumor necrosis factor agents. However, the reliability of interferon-γ release assays in detecting tuberculosis infection among HTLV-1-positive patients with rheumatoid arthritis (RA) remains unclear. The present study aimed to evaluate the use of the T-SPOT.TB assay in HTLV-1-positive RA patients.

Methods

Overall, 29 HTLV-1-positive RA patients and 87 age- and sex-matched HTLV-1-negative RA patients (controls) were included from the HTLV-1 RA Miyazaki Cohort Study. Results of the T-SPOT.TB assay for latent tuberculosis infection screening were collected from medical records of patients.

Results

Approximately 55% of the HTLV-1-positive RA patients showed invalid T-SPOT.TB assay results (odds ratio: 108, 95% confidence interval: 13.1–890, p < 0.0001) owing to a spot count of >10 in the negative controls. HTLV-1 proviral load values were significantly higher in patients with invalid results compared with those without invalid results (p = 0.003).

Conclusion

HTLV-1 infection affects T-SPOT.TB assay results in RA patients. Assay results in HTLV-1 endemic regions should be interpreted with caution when screening for latent tuberculosis infection before initiation of biologic therapy.

Meningitis associated with strongyloidiasis in an area endemic for strongyloidiasis and human T-lymphotropic virus-1: a single-center experience in Japan between 1990 and 2010

Meningitis caused by enteric flora is a known complication of strongyloidiasis, and human T-lymphotropic virus-1 (HTLV-1) predisposes individuals to severe strongyloidiasis. We reviewed the clinical features of bacterial meningitis associated with strongyloidiasis seen at a single center in subtropical Japan, in an area endemic for both strongyloidiasis and HTLV-1. We found 33 episodes in 21 patients between 1990 and 2010. The results were remarkable for the high incidence of meningitis due to Gram-positive cocci (27.3 %), especially Streptococcus bovis, and culture-negative cases (42.4 %). Given the high incidence of Gram-positive meningitis, a modified approach to corticosteroid use would be advisable in areas where strongyloidiasis is endemic, due to the potentially adverse consequences of glucocorticoid therapy.

Human T-lymphotropic virus type I infection and idiopathic thrombocytopnic purpura

Human T-lymphotropic virus type I (HTLV-I) is the causative agent in adult T-cell leukemia and HTLV-I associated myelopathy. Some other diseases such as uveitis, chronic thyroiditis, Sjögren syndrome, arthritis, acute myeloid leukemia and myelodysplastic syndrome may be also associated with HTLV-I. Several case reports have suggested the possible combination of idiopathic thrombocytopenic purpura (ITP) and HTLV-I infection. In these studies and from our current report, we found 17 patients (22.1%) with HTLV-I infection among 77 ITP patients. The prevalence of HTLV-I infection among ITP patients was higher than that of healthy volunteers (5 approximately 10%). The ITP patients with HTLV-I infection were older than the patients without HTLV-I infection, and the ITP patients with HTLV-I infection had poor response to prednisolone therapy. Among 17 ITP patients with HTLV-I infection, 9 patients received prednisolone therapy. Although most patients had transient increase of platelet counts, only two of them had partial responses (PR) at the last observation date. Five patients underwent splenectomy, and four of them had complete responses (CR) and the remaining patient had a (PR). Four patients received eradication of Helicobactor pylori (H. pylori) infection, and all patients had CRs. Therefore, the ITP patients with HTLV-I infection should receive eradication therapy in the case of H. pylori infection as the first step of therapy and the splenectomy should be considered, if there is no response to conventional therapy. Human immunodeficiency virus (HIV) causes thrombocytopenia in 10% of patients with active HIV disease. The etiologies of HIV thrombocytopenia are considered as follows, the escalated destruction of platelets by the immune system, damage to megakaryocytes by HIV infection and the inhibition of thrombopoiesis by some anti-viral drugs. In the case of ITP patients with HTLV-I infection, the main etiology may be the increased destruction of platelets by immune system. The proviral load and the integration pattern of HTLV-I should be examined to clarify the stage of HTLV-I infection. The possibility of infection of the megakaryocytes by HTLV-I should be also examined for etiological approach.

Tuberculous meningoencephalomyelitis and coinfection with HTLV-I + HTLV-II: case report

HTLV-I and HTLV-II are endemic in some areas of Brazil, where an associated disease, HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP) have been diagnosed in significant number of infected individuals. Tuberculosis has been demonstrated among those individuals, with higher prevalence than in the general population, suggesting that there is an increased risk for this comorbidity. We report the case of an individual coinfected with HTLV-I and HTLV-II, suffering from an insidious meningoencephalomyelitis caused by Mycobacterium tuberculosis. The patient was a 44 years old man successfully treated with steroids and antituberculous drugs, improving clinically and turning to a negative PCR and to a normal blood-cerebrospinal fluid barrier.

Predictive markers for development of strongyloidiasis in patients infected with both Strongyloides stercoralis and HTLV-1

Severe strongyloidiasis has often been reported to occur in some patients infected with both Strongyloides stercoralis (S. stercoralis) and human T-cell leukaemia virus type 1 (HTLV-1); however, there are few useful predictive markers for the risk of development of strongyloidiasis in these patients. To search for such predictive markers, we examined peripheral blood and stool samples of individuals infected with both S. stercoralis and HTLV-1 in Okinawa, Japan, an area in which both of these are endemic. The HTLV-1 proviral load and antibody titre were examined in relation to the S. stercoralis load as measured by the direct faecal smear method in patients infected with both S. stercoralis and HTLV-1. The Epstein-Barr virus (EBV)-associated nuclear antigen (EBNA) antibody titre was also measured in these patients in order to examine the relationship between host immunity and HTLV-1 proviral load or antibody titre. The direct faecal smear-positive group showed both a higher HTLV-1 proviral load and HTLV-1 antibody titre than the -negative group (P < 0.05). In contrast, inverse correlations of these parameters with the EBNA antibody titre were observed, especially for proviral load (rho = -0.387, P < 0.05). These results suggest that HTLV-1 proviral load and antibody titre influence the S. stercoralis load via disturbance of the host immunity, and that proviral load would be an especially useful predictive marker of the risk of development of strongyloidiasis in patients infected with both S. stercoralis and HTLV-1.

Risk factors for HTLV-I and II in individuals attending a clinic for sexually transmitted diseases

BACKGROUND

To date, few studies have provided information on risk factors for human t-lymphotropic viruses (HTLV) types I and II in European countries. In particular, few data are available from published studies conducted in STD centers.

GOALS

To identify risk factors for HTLV-I and HTLV-II infection and to better distinguish the epidemiologic patterns of the two viruses in Italy.

STUDY DESIGN

A cross-sectional study of individuals at high risk of sexually or parenterally transmitted infections attending a large STD center in an urban setting was conducted. Serologic tests for HTLV-I and II, HIV, hepatitis virus type B (HBV), hepatitis virus type C (HCV), and syphilis were performed. Information regarding at-risk behavior was collected using a specific questionnaire.

RESULTS

From January 1994 to June 1996, 1,457 individuals were recruited; of them, 1,016 (69.7%) were males, 1,051 (72.4%) Italians, and 288 (19.8%) non-Europeans. One thousand seventy-five (74.8%) participants were noninjecting-drug-using heterosexuals, 285 (19.6%) were men who have sex with men, and 97 (6.6%) were injecting drug users (IDU). The mean age of the study participants was 33.6 (+/-10.5) years. Nine (0.6%) individuals were positive for HTLV-I antibodies and 9 (0.6%) for HTLV-II antibodies. The prevalence of HTLV-I among IDUs, men who have sex with men, and noninjecting-drug-using heterosexuals, was 2.1% (2/97), 1.4% (4/ 285), and 0.3% (3/1085), respectively. HTLV-II prevalence was 8.2% (8/97) among IDUs and 0.09% (1/1075) among noninjecting-drug-using heterosexuals. Among the nine HTLV-II-positive individuals, eight were Italian IDUs and one was a noninjecting-drug-using heterosexual man from India. None of the 285 men who have sex with men had HTLV-II antibodies. HTLV-infected individuals tended to be older than those who were uninfected. HTLV-I-infected individuals were more likely to be non-European and to have antibodies against Treponema pallidum. Injecting drug use tended to be independently associated with HTLV-II infection.

CONCLUSIONS

The data suggest a role of sexual behavior in the spread of HTLV-I, which is more likely to be detected in individuals coming from endemic areas. Injecting drug use remains the most important risk factor for HTLV-II infection in Italy.

HTLV-I infection in squirrel monkeys (Saïmiri sciureus) using autologous, homologous, or heterologous HTLV-I-transformed cell lines

Peripheral blood mononuclear cells (PBMC) from three adult male squirrel monkeys (Saïmiri sciureus) were transformed by human T-cell leukemia/lymphoma virus type I (HTLV-I) by cocultivation with lethally irradiated human MT-2 cells. Three permanent monkey T-cell lines producing HTLV-I were obtained and characterized. Six weeks after inoculation seroconversion was observed in three of three monkeys inoculated with autologous transformed T cells and in two of three monkeys receiving homologous cells. Proviral DNA was detected in their PBMC at various times after inoculation, with the highest proviral load and antibody titers being found in monkeys infected with homologous cells. Monkeys inoculated with heterologous MT-2 cells did not seroconvert, and HTLV-I provirus was detected only transiently in their PBMC. To determine whether in vitro and in vivo HTLV-I infection of squirrel monkey cells led to a selection of monkey-adapted viral mutants, comparative sequencing of the proviral gp21 env between ex vivo monkey HTLV-I-infected PBMC, the inoculum, and MT-2 cells was done and no significant differences were detected. The squirrel monkey, which is naturally free of simian T-cell leukemia/ lymphoma virus, thus appears to be a suitable model for evaluating HTLV-I candidate vaccines and for studying the pathogenesis of HTLV-I.

Marked inhibition of the intracellular multiplication of Legionella pneumophila in monocytes isolated from carriers of human T lymphotrophic virus type I

Intracellular growth patterns of Legionella pneumophila were examined in monocytes obtained from carriers of human T-lymphotropic virus type I (HTLV-1) and controls who were HTLV-1 seronegative. All subjects were seronegative for antibodies against L. pneumophila. Bacterial growth was determined 0, 1, 2, and/or 3 days after infecting peripheral blood mononuclear cells (PBMCs) with the bacteria. The intracellular growth of L. pneumophila was markedly inhibited in HTLV-1 carriers compared with normal controls. When the lymphocytes were depleted from the HTLV-1 carrier PBMC cultures before infection, this inhibition was abolished. Inhibition reappeared, however, when the 72-h culture supernatants of PBMCs from HTLV-1 carriers were added to the lymphocyte-depleted cultures. Culture supernatants of infected and uninfected PBMCs from HTLV-1 carriers exhibited markedly increased levels of interferon-gamma (IFN-gamma) and tumor necrosis factor alpha (TNF-alpha) compared with the HTLV-1 seronegative controls. In the HTLV-1 carriers, IFN-gamma was produced by the CD4+ lymphocytes, whereas TNF-alpha was secreted by the monocytes. Addition of anti-IFN-gamma or anti-TNF-alpha antibodies to the HTLV-1 carrier PBMC cultures diminished the inhibition of intracellular growth of L. pneumophila. Results suggest that the monocytes are activated in HTLV-1 carriers. These findings may explain why an opportunistic infection by certain intracellular pathogens is rarely seen among HTLV-1 carriers.

Constitutive expression of various chemokine genes in human T-cell lines infected with human T-cell leukemia virus type 1: role of the viral transactivator Tax

We examined the genetic expression of 2 CXC chemokines (IL-8, IP-10), 5 CC chemokines (MCP-1, MIP-lalpha, MIP-1beta, RANTES, 1309) and 1 C chemokine (SCM-1/lymphotactin/ATAC) in various human T-cell lines. By Northern blot analysis, HTLV-1-positive T-cell lines were found to express a number of chemokine genes at variable levels and in different combinations. However, none of the chemokine genes was expressed in HTLV-1-negative T-cell lines. We further confirmed secretion of 3 chemokines (IL-8, MIP-1alpha and RANTES) by some HTLV-1-positive T-cell lines. To examine the role of the HTLV-1-encoded transactivator Tax in the induction of these chemokine genes, we used JPX-9 and JPX-M, which were stably transformed with tax and non-functional tax, respectively, under the control of a metallothionein promoter. Induction of tax in JPX-9 with Cd2+ was accompanied by rapid induction of IL-8, IP-10, MIP-1alpha, MIP-1beta, 1309 and SCM-1 as determined by reverse transcription PCR. No such induction was seen in JPX-M. We thus suggest that Tax is, at least in part, responsible for constitutive expression of certain chemokine genes in HTLV-1-infected T cells. Aberrant production of various chemokines by HTLV-1- infected T cells may impact on the pathophysiology of HTLV-1-associated diseases.

Dependency of antibody titer on provirus load in human T lymphotropic virus type I carriers: an interpretation for the minor population of seronegative carriers

To evaluate the prevalence of seronegative carriers of human T lymphotropic virus type I (HTLV-I), buffy coat samples from 1015 Okinawan high school students were tested by immunoassays and nested polymerase chain reaction (PCR). Among 17 HTLV-I carriers, 1 person who was seronegative and 1 who was PCR-negative were identified. gag and tax/rex PCR titers correlated with each other (r = .92; P < .001). Of the 17 carriers, 14 (82%) had high virus loads (geometric averages, 522 gag and 703 tax/rex copies/micrograms of DNA; 95% confidence intervals, 38-7260 and 75-6594, respectively). Carriers with low virus loads had < or = 2.2 gag copies. In the high-virus-load group, the gag PCR titers correlated with the antibody titers (r = 0.88; P < .001). The regression line intersected the minimum antibody detection level at 35 gag copies/micrograms of DNA. These results suggest that a small percentage of carriers may be seronegative.

Virions released from cells transfected with a molecular clone of human T-cell leukemia virus type I give rise to primary and secondary infections of T cells

The ability of molecular clones of human T-cell leukemia virus type I (HTLV-I) to direct the synthesis of infectious virions has not previously been demonstrated. An HTLV-I provirus originating from an adult T-cell leukemia patient was cloned into a plasmid vector and is designated pCS-HTLV. This molecular clone was shown to direct the synthesis of viral mRNA and proteins in transiently transfected cells; in addition, virus structural proteins were released into the culture medium. Viral proteins were assembled into virions that sedimented at a buoyant density characteristic of retrovirus particles and whose morphology was verified by electron microscopy. Virions concentrated from transiently transfected cell supernatants were incubated with primary cord blood lymphocytes or with transformed T-cell lines to establish that these particles were infectious. Expression of spliced, viral mRNAs in the T-cell cultures after both primary and secondary infections with cell-free virus revealed that pCS-HTLV encodes an infectious provirus.

Virus production and spontaneous cell proliferation in HTLV-I-infected lymphocytes

Cultured peripheral blood lymphocytes (PBL) from HTLV-I-infected individuals proliferate in the absence of added mitogens and/or cytokines. In an attempt to answer questions regarding the activating signals for cells and virus, antibodies that react with cell surface components that are known to regulate cell activation and antibodies reacting with viral proteins were added to cultures of PBL from HTLV-I-infected, disease-free individuals. Spontaneous proliferation and virus production increased in the presence of antibodies reacting with CD3 and alpha/beta T cell receptors (TCR) while antibodies to HLA class II and viral proteins had no effect. Addition of HLA class I antibodies shut down virus production and cell proliferation. These observations indicate that both virus and cell activation may occur through the alpha/beta TCR on the infected cell. Cyclosporin A, however, markedly decreased cell proliferation but had only a modest suppressive effect on virus production. Thus, the uncoupling of cell proliferation from virus production by cyclosporin A suggests the possibility that the signal transduction pathways for these two events are different.

Primate T-lymphotropic virus type I LTR sequence variation and its phylogenetic analysis: compatibility with an African origin of PTLV-I

Due to the low evolutionary rate and the limited horizontal transmission of human T-lymphotrophic virus type I (HTLV-I), its phylogenetic analysis reveals the movements and contacts of ancient populations. Since simian strains cannot be distinguished from human strains by phylogenetic criteria, this virus has appropriately been called primate T-lymphotropic virus type I (PTLV-I). We sequenced the LTR of six PTLV-I strains: three HTLV-I strains from African patients with tropical spastic paraparesis (TSP) (Equateur, Zaire), two laboratory HTLV-I strains of Japanese origin, MT-2 and MT-4, and one STLV-I from a baboon of the primate center in Sukhumi, Georgia. We applied four phylogenetic inference methods: neighbor-joining (NJ), unweighted pair group method using arithmetic averages (UPGMA), Fitch and Wagner parsimony (pars), and maximum likelihood (ML), to these 6 LTR sequences and 18 published LTR sequences (cosmopolitan, African, and Melanesian HTLV-I strains and African and Asian STLV-I strains). Three major HTLV-I subtypes can be identified with all four methods: the cosmopolitan HTLV-Ia, the central African HTLV-Ib, clearly descendant from a STLV-I CH-like African ancestral simian strain, and the Melanesian HTLV-Ic, probably descendant from an Asian STLV-I strain. We observe a segregation of PTLV-I sequences according to their geographical origin and not according to host species. The Zairean strains form a cluster closely related to an STLV-I strain isolated from a chimpanzee (STLV-I CH) and distinct from western African strains, which belong to the cosmopolitan subtype of HTLV-I. The Sukhumi STLV-I strain found in a captive-born baboon was of Asian descent. We experienced rooting problems with UPGMA when using HTLV-II as an outgroup. Concordant results with all four methods were obtained by eliminating HTLV-II LTR sequence fragments with bad alignment to HTLV-I. This resulted in a HTLV-II root node on the African STLV-I TAN90 terminal branch (with bootstrap values above 92% for the NJ and pars methods) and not on the Asian STLV-I PtM3 branch, as has been derived by others based on their use of UPGMA. The results of the analyses also support a higher evolutionary rate of PTLV-I in Asia, implying that the trees obtained with the NJ and ML methods have a higher reliability. These results are more compatible with an ancient African origin of PTLV-I than with an Asian origin.

Regional specificity of HTLV-I proviral integration in the human genome

The location of HTLV-I (human T-cell leukemia virus type 1) proviral sequences in the genome of infected human cells was explored by hybridization of a viral probe with compositional fractions of host-cell DNAs. In the twelve cases examined, HTLV-I sequences were absent from the GC-poorest 40% of the host genome (namely, from isochores that are below 39% GC). Transcriptionally inactive proviral sequences were localized in GC-poor isochores (comprised between 39% and 42-44% GC) of the human genome, which are characterized by a constant and low gene concentration. In contrast, transcriptionally active proviral sequences were found in the GC-rich and very GC-rich isochores, which are gene rich, transcriptionally and recombinationally active, and endowed with an open chromatin structure. Since GC-rich isochores are present in R'-bands and very GC-rich isochores form T-bands, these results also provide information on the location of HTLV-I proviral sequences in human chromosomes. The results obtained with HTLV-I are in agreement with the non-random, compartmentalized integration of animal retroviral sequences that had been previously observed in other viral-host systems. They provide, however, much more detailed information on the regional location of proviral sequences in the host genome and on the correlation between their transcription and their location.

[Detection of HTLV-I proviral DNA by PCR method from bronchoalveolar lavage cells of HTLV-I carriers]

To elucidate whether or not human T-lymphotropic virus type I (HTLV-I) infected cells exist in the lungs of HTLV-I carriers, we examined bronchoalveolar lavage (BAL) cells for the presence of HTLV-I proviral DNA by the polymerase chain reaction (PCR) method. The cells were harvested from HTLV-I seropositive individuals with or without various respiratory diseases. The HTLV-I pX region was detected from separated BAL cells by dot blot hybridization after PCR in all 14 HTLV-I seropositive individuals tested. Four out of these 14 individuals were asymptomatic HTLV-I carriers, while the other ten had symptoms, including those of bacterial pneumonia, chronic respiratory tract infection, interstitial pneumonia, atypical mycobacterial infection, bronchitis, mediastinal lymphadenitis and bronchial asthma. HTLV-I proviral DAN was detected in BAL cells from patients with a normal proportion of lavage lymphocytes and a normal CD4/CD8 ratio. These findings suggest that HTLV-I infected cells may commonly exist in the lower respiratory tract and alveolar space without producing characteristic symptoms/signs, and that any causal relation to the pulmonary lesion must therefore be carefully elucidated, in HTLV-I carriers.

Single amino acid substitution (58Pro-->Ser) in HTLV-I tax results in loss of ras cooperative focus formation in rat embryo fibroblasts

Two tax genes cloned from a healthy HTLV-I carrier in whom the viral genome is clonally integrated into peripheral CD4+CD8+ cells showed a considerable difference in ras cooperative focus forming ability in rat embryo fibroblasts (REF). Sequence analysis revealed differences in two codons of the two genes. SH-1tax and SH-2tax. Studies using recombinants between these two tax genes showed that the deficiency in ability of SH-1tax to cooperate with ras in focus formation in REF was caused by a 58Pro-->Ser substitution. This amino acid substitution did not affect other tax functions such as colony formation in soft agar, focus formation in Rat-1 cells, immortalization of REF, and transcriptional activation through the CREB/ATF and NFkB/rel pathways. These results suggest that the domain of tax required for cooperative focus formation with ras in primary rat fibroblasts may be different from those required for other tax functions.

Expression of human T lymphotropic virus type 1 (HTLV-1) tax/rex gene in fresh bronchoalveolar lavage cells of HTLV-1-infected individuals

Accumulating evidence has suggested the involvement of HTLV-1 in the inflammatory lesions of various organs, including the lung. However, the causal relationship between HTLV-1 and inflammatory responses in the organs remains to be elucidated. In order to evaluate the expression of HTLV-1 and its effects in the lung, we examined the expression of mRNA for the HTLV-1 tax/rex gene in fresh bronchoalveolar lavage cells (BALC) and peripheral blood mononuclear cells (PBMC) of 23 seropositive individuals, including six patients with HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP), by use of an improved method of reverse transcription-polymerase chain reaction (RT-PCR). The tax/rex mRNA was more frequently detected in BALC than in PBMC. All the HAM/TSP patients and eight of 17 carriers without neurological symptoms showed the expression of tax/rex mRNA in the BALC. IgM class antibodies to HTLV-1 were preferentially detected in sera of the tax/rex mRNA-positive individuals. The detection of tax/rex mRNA correlated closely with the presence of lymphocytosis accompanied by an elevated proportion of IL-2 receptor-bearing T cells in the BALC. Our findings indicate the crucial role of viral expression in the inflammatory response in the lung in HTLV-1-infected individuals.

A spontaneous point mutation in the human T-cell leukemia virus type 1 pX gene leads to expression of a novel doubly spliced pX-mRNA that encodes a 25-kD, amino-terminal deleted rex protein

Primary RNA transcripts of the human T-cell leukemia virus type 1 (HTLV-1) are processed into mature mRNA by a complex series of splicing events. In this paper, we report the finding of a novel doubly spliced pX mRNA in two out of eight HTLV-1-infected cell lines and in one out of 13 peripheral blood mononuclear cells from HTLV-1-infected individuals. The second splicing for this novel pX mRNA is different from that for the known doubly spliced pX mRNA. A novel acceptor site in this splicing was generated by a single point mutation (G to A) at nucleotide 7,337 of the pX gene. This mRNA contained a complete open reading frame that encodes an amino-terminal truncated p27rex protein with 189 amino acids. A new 25-kD protein was detected in the cell lines expressing the novel pX mRNA by an antibody against the carboxy-terminal peptide of p27rex and was termed p25rex. Although the function of p25rex is not clear, we clarified that p25rex is a cytoplasmic phosphoprotein and its function is different from the transcriptional regulator function of p27rex. The possibility that the mutated virus is replicable only in cells coinfected with the wild type HTLV-1 may explain why the incidence of the mutants observed here is low.

Evaluation of a p21e-spiked western blot (immunoblot) in confirming human T-cell lymphotropic virus type I or II infection in volunteer blood donors. The Retrovirus Epidemiology Donor Study Group

Current algorithms for the serologic confirmation of human T-cell lymphotropic virus type I and II (HTLV-I/II) antibody reactivity are complicated. We evaluated the performance of an HTLV-I Western blot (immunoblot) spiked with recombinant p21e protein (p21e WB) as an alternative to current confirmatory methods. These methods include the HTLV-I viral lysate Western blot and either a radioimmunoprecipitation assay or a p21e enzyme-linked immunosorbent assay. Five hundred fifty nine blood donations obtained from five U.S. blood centers and classified as HTLV-I/II seropositive (n = 149) or seroindeterminate (n = 410) by routine testing methods were further evaluated by PCR for proviral DNA and by the p21e WB. On the basis of serologic and PCR testing, 155 donations were classified as HTLV-I/II infected. The sensitivity of the p21e WB was 97.4%, slightly exceeding that of routine confirmatory testing. The specificity of the p21e WB was 97.5%, as determined by testing of 404 seroindeterminate samples that were negative in the PCR. The positive predictive value of the p21e WB was 94%. In contrast, the specificity and positive predictive value of routine confirmatory testing were both 100%. Follow-up sampling of presumptive p21e WB false-positive donors substantiated the absence of HTLV-I/II infection. Although the p21e WB used in this study has high sensitivity and may be useful as a confirmatory assay in epidemiologic research studies, it may not be ideal as a confirmatory test for the notification of blood donors.

Microplate-based DNA hybridization assays for detection of human retroviral gene sequences

Nonisotopic, microwell-based DNA hybridization assays for the specific detection of human immunodeficiency virus type 1 (HIV-1) gag, human T-cell lymphotropic virus type I (HTLV-I) pol, and HTLV-II pol DNA sequences were evaluated. The performances of these detection kits (Gene Detective enzyme oligonucleotide assays; Cellular Products, Inc., Buffalo, N.Y.) were assessed by using clinical samples whose infection status were established by amplification by PCR and then liquid hybridization detection by using virus-specific probes. Peripheral blood mononuclear cell lysates from 59 HIV-1-, 35 HTLV-I-, and 19 HTLV-II-infected individuals and from 15 healthy blood donors were used as substrates for PCR amplification. The results of the study demonstrated a clinical sensitivity of 100%. In addition, the enzyme oligonucleotide assays were able to detect 1 to 10 proviral copies subsequent to PCR amplification, indicating an analytical sensitivity comparable to that of liquid hybridization.

Isolation, characterization, and transmission of human T-lymphotropic virus types I and II in culture

Highly sensitive coculture methods were developed both for isolation of human T-lymphotropic virus types I and II (HTLV-1 and HTLV-II) from infected individuals and for productive infection of lymphoid cells. Mitogen-activated peripheral blood mononuclear cells (PBMC) from 13 HTLV-I- and 20 HTLV-II-positive specimens were cocultured with an equal number of mitogen-activated PBMC from HTLV-seronegative individuals, and culture supernatants were tested for the presence of soluble p24gag antigens at weekly intervals for 4 weeks. Eleven of 13 (85%) HTLV-I and 14 of 20 (70%) HTLV-II cultures were positive for p24 antigens. None of the 17 HTLV-seroindeterminate or six HTLV-seronegative specimens were positive for the presence of p24 antigen. The isolation rates for HTLV-I and HTLV-II by an alternative whole-blood lysis procedure were comparable to those obtained by standard PBMC cultures. Furthermore, cocultivation of PHA-stimulated PBMC from healthy donors with lethally irradiated HTLV-I- and HTLV-II-infected cell lines (SP and Mo-T, respectively) resulted in productive viral infection, as reflected by the appearance of p24gag antigens concomitant with specific genomic amplification of HTLV proviral DNA after 3 weeks of cocultivation. Thus, the cocultivation technique provides a highly sensitive and specific procedure both for HTLV isolation and for infection of target cells.

Establishment of HTLV-I-infected cell lines from French, Guianese and West Indian patients and isolation of a proviral clone producing viral particles

Human T-cell leukemia virus (HTLV-I) induces adult T cell leukemia/lymphoma (ATL) and a chronic neurological disease named either tropical spastic paraparesis (TSP) or HTLV-I associated myelopathy (HAM). We report here the establishment and characterization of eight HTLV-I-infected lymphoid cell lines derived either from patients with TSP (5) or from asymptomatic carriers (1). Southern blot analysis of T cell beta chain gene rearrangements indicates that all cell lines are composed of clonal populations. The same type of analysis performed with HTLV-I-specific probes showed that they harbor 1 to 5 copies of full length proviruses often associated with deleted proviruses with a restriction map for BamHI, HindIII, PstI and SacI restriction enzymes resembling those of HTLV-I previously isolated from Japan and Caribbean area. One of the cell lines, 2060, derived from a TSP patient was shown to express a relative large amount of virus easily transmissible to fresh peripheral and cord blood lymphocytes. The full length proviral genome contained in this cell line was cloned and used in transient expression experiments. We showed that the cloned provirus was able to direct the synthesis of the major structural viral proteins, the protease and the tax and rex regulatory proteins. The structural viral proteins could be assembled into free particles detected in the culture medium of transfected cells. Although the infectivity of these viral particles remains to be determined, this new clone can be employed to examine the cell types in which this TSP-derived provirus directs viral protein synthesis and eventually replicates. It should also prove of value in studies on the early cellular events induced by viral products.

Unintegrated two-long terminal repeat circular human T lymphotropic virus DNA accumulation during chronic HTLV infection

Accumulation of unintegrated human T lymphotropic virus (HTLV) DNA was analyzed in long-term T cell lines infected with HTLV type I (HTLV-I) or type II (HTLV-II). By using a polymerase chain reaction-based assay, amplified products of expected size were obtained in all of the HTLV-I-infected (n = 7) and HTLV-II-infected (n = 8) cell lines. The signal intensities of the hybridizing band varied greatly among the cell lines and did not correlate with HTLV p24gag antigen production. Further analysis of HTLV-I-infected clones demonstrated considerable variability in the unintegrated DNA accumulation, suggesting that either the epigenetic status of the host cell or some environmental factor determines the occurrence of unintegrated DNA. The presence of lower levels of unintegrated DNA in most of the HTLV-infected, long-term cell lines presumably results in persistent noncytopathic infection.

Mice transgenic for HTLV-I LTR-tax exhibit tax expression in bone, skeletal alterations, and high bone turnover

HTLV-I infection can result in adult T cell leukemia with accompanying hypercalcemia and increased bone resorption. A viral etiology has also been invoked for Paget's disease, a disease of high bone turnover. Delineation of pathogenetic mechanisms of viral-associated bone diseases has been impeded by the complexity of viral and host factors. In order to consider the relationship of HTLV-I infection to skeletal changes we have evaluated the role of a single viral gene in mice transgenic for HTLV-I tax under the control of the viral promoter. Tax mice exhibited severe skeletal abnormalities characterized by high bone turnover, increases in osteoblast and osteoclast numbers and activity, and myelofibrosis. These changes were apparent as early as two months of age. Tax mRNA and protein were highly expressed in bone but not in bone marrow nor in any other tissues except, as previously reported, salivary gland and neurofibromas when they did develop. Within bone, tax protein was detected in only two cell types, mature osteoclasts and spindle-shaped cells within the endosteal myelofibrosis. These observations suggest that local expression of the tax gene, which encodes a viral regulatory protein known to influence host gene expression, can induce within the bone environment marked changes in bone cell activity, resulting in profound skeletal alterations.

Retroviruses and inflammatory myopathies in humans and primates

The human immunodeficiency virus (HIV), the human T cell lymphotropic virus (HTLV-1), the human foamy retrovirus and the simian immunodeficiency viruses have been associated with the development of an inflammatory myopathy in humans and primates. The myopathy caused by HIV and HTLV-1 is not due to direct infection of the muscle by these viruses, but rather due to an immunopathologic process triggered by the viruses, mediated by autoaggressive CD8+ cells in the context of MHC-class I antigen expression. This has been based on a series of studies utilizing immunocytochemistry, in situ hybridization, polymerase chain reaction, and co-cultivation of human myotubes with the viruses or with HIV-1 and HTLV-1-infected homologous lymphoid cells. Because the clinical, histological and immunological picture of patients with retroviral-associated inflammatory myopathies is identical to that of patients with retroviral-negative inflammatory myopathy, there is a reasonable possibility that retroviruses may be candidate viruses in triggering inflammatory myopathies. In recent years, the antiretroviral drug AZT (Zidovudine), commonly used for the treatment of AIDS, has been shown to cause a distinct mitochondrial myopathy characterized by depletion of the muscle mitochondrial DNA due to AZT's ability to inhibit the gamma-DNA polymerase of the mitochondrial matrix. Distinction of the AZT-myopathy is clinically important because it responds to discontinuation of AZT and to administration of another antiretroviral agent such as ddI or ddC.

Complete sequence conservation of the human T cell leukaemia virus type 1 tax gene within a family cluster showing different pathologies

We have amplified, through PCR, the full-length tax gene of human T cell leukaemia virus type 1 (HTLV-1) derived from proviral DNA of peripheral blood lymphocytes of five first degree relatives of Afro-Caribbean origin. One patient (the father) had adult T cell leukaemia (ATL), one (the mother) tropical spastic paraparesis (TSP), and three (children) were healthy asymptomatic carriers. All five family members had identical tax nucleotide sequences as determined by direct sequencing of PCR products. This sequence was compared with tax gene sequences of an unrelated TSP patient of Afro-Caribbean origin, and of C8166 cells, and found to have one and seven nucleotide differences, respectively. At the amino acid level these three sequences differed from the HTLV-1 prototype Japanese strain (ATK-1). All sequence changes were clustered towards the 3' end of the gene. These data demonstrate the complete conservation of an HTLV-1 gene following, presumably, horizontal and vertical transmission of the virus. Clones of this gene showed more sequence variation within the TSP patient than the ATL patient, mostly consisting of point mutations; there was no conservation of mutations between the two individuals. These mutations occurred only in individual clones of the ATL patient whereas those of the TSP patient were found to be repeated in different clones. A tax-specific cytotoxic T lymphocyte response was observed in two asymptomatic carriers with low antibody titres, whereas none was detected in an individual with a high antibody level. No tax-specific sequence was identified which may have contributed to the apparently high degree of transmission from mother to children (three of five children tested) nor account for the differences between disease symptoms in the parents.

Quantitation of HTLV-I provirus among seropositive blood donors: relation with antibody profile using synthetic peptides

To study the pathophysiological state of HTLV-I carriers and the quantitative aspect of the risk of HTLV-I infection, we measured the absolute amounts of HTLV-I provirus in 39 seropositive blood donors. The amount of provirus varied from less than one to more than 10(4) molecules per 10(5) peripheral-blood mononuclear cells (PBMC). The average amount of HTLV-I provirus among seropositive blood donors was estimated as 3.7 x 10(3) molecules per 10(5) PBMC. The titer of the antibody against only the synthetic peptide (aa 100 to 130) of the gag p19 region of the HTLV-I provirus showed a weak but significant correlation with the amount of the provirus.

HTLV-I maternal transmission in Martinique, using serology and polymerase chain reaction

We have investigated HTLV-I and HTLV-II infection in children born to HTLV-I-seropositive or indeterminate Western blot mothers in Martinique by using the polymerase chain reaction (PCR). Only HTLV-I and no HTLV-II-positive samples were found in this study. All the samples from HTLV-I-seropositive children and adults were PCR positive, whereas the four HIV-I-seropositive and Western blot HTLV-I-negative mothers and their eight children were all PCR negative. Therefore, PCR and serology were in complete agreement in these patients. However, two of the six mothers who were first indeterminate by Western blot, and who later became seronegative, were found positive by PCR. Of the 27 children (ages 2-12 years), born to HTLV-I-seropositive and PCR-positive mothers, 2 were seropositive and PCR positive, 5 were seronegative and PCR positive with 2 primer pairs in gag and pol, and 4 were seronegative and PCR positive with only 1 of the primer pairs. In contrast to an initial rate of transmission of 7% estimated by serology we found a rate of transmission of 28 to 41% (whether or not children who were positive with only one of the primer pairs were included). Thus, our study confirms that PCR is useful in detecting HTLV-I infection in children before seroconversion and underlines the potential lack of sensitivity of serology to detect contaminating HTLV-I blood units in endemic areas.

HTLV-I sequence in lymphoproliferative disorders

Several recent studies reported the detection of partially deleted HTLV-I provirus in biopsies of lesions from patients with mycosis fungoides (MF) and T-cell anaplastic large-cell lymphoma. We studied lesions from 59 patients (21 B-cell lymphomas: 16 diffuse and five follicular; 11 cutaneous T-cell lymphomas, including seven MF; one T-immunoblastic lymphoma; 10 diffuse anaplastic large-cell lymphomas: two B, four T, and four of indeterminate phenotype; three Hodgkin's lymphomas; eight atypical lymphoid proliferations; four other lymphoid lesions, and one squamous-cell carcinoma) using primers to the gag, pol and pX regions of HTLV-I in the polymerase chain reaction (PCR) to detect relevant sequences. A total of 10 patients showed one or more PCR-amplifiable products, including five of 11 patients with cutaneous T-cell lymphomas (45%) as compared with one of 21 patients with B-cell lymphomas (4.3%). We did not find a high incidence of positivity in anaplastic large-cell lymphomas, as reported previously. Detectable HTLV-I sequences were not limited to any subtype of lymphoma, and a pX sequence was detected in a squamous-cell carcinoma. Sequence analysis of one amplified product from each of the three regions studied showed a 94.2, 100, and 98.9% homology to the corresponding prototypical gag, pol, and pX HTLV-I sequences, respectively, indicating that the amplified sequences were derived from HTLV-I or a very closely related virus. HTLV-I sequences were detected in a significant proportion of patients with cutaneous T-cell lymphoma, but their role in the pathogenesis of the neoplasm is still unclear.

Variation in HTLV-I sequences from rabbit cell lines with diverse in vivo effects

Comparison of nucleotide sequences determined for HTLV-I integrated provirus from two rabbit cell lines, RH/K30 and RH/K34, revealed greater than 99% identity to one another. Substitutions encoding amino acid interchanges were observed in the gag, pol, and rex regions whereas the env and tax proteins were identical in the two lines. Comparison with the human prototypic HTLV-I sequence revealed considerably more variation, especially in the viral envelope region where the rabbit sequences are identical. The HTLV-I lines differed in their potential to cause disease in rabbits: injection of the RH/K34 cell line caused human adult T-cell leukemia/lymphoma-like (ATLL) disease which was fatal within 10 days, whereas all rabbits injected with the same or higher doses of RH/K30 survived with a low-grade leukemia that showed evidence of acute rejection. Correlation of lethality with viral sequence was tested by injection of rabbits with two other rabbit cell lines with HTLV-I provirus identical to RH/K34 in LTR, gag, and env regions. The fact that only one of these lines produced fatal disease suggests that pathogenic determinants lie outside of these regions or, alternatively, that the structure of the integrated virus is not the sole factor in the cell lines' ability to cause ATLL-like disease.

Detection of human T-cell lymphotropic virus type 1 infection by the polymerase chain reaction using dried blood specimens on filter papers

A simple method for detection of proviral DNA sequences of human T-cell lymphotropic virus type 1 (HTLV-1) was developed using dried blood specimens on filter papers. The whole blood was blotted onto the Guthrie paper. After the blood has dried, the blotted paper was punched out into small discs. The discs were then boiled to prepare the template for PCR (filter paper-PCR method). The filter paper-PCR method detected even a single HTLV-1-infected cell in three discs. The sensitivity of the filter paper-PCR method was equivalent to that of the method in which DNA was extracted with phenol and used as the template for PCR (DNA extraction-PCR method). In addition, DNA in the blotted filter paper was still utilizable as the template after the storage at 25 degrees C for at least 7 wk. A total of 53 clinical specimens from 30 seropositive and 23 seronegative individuals who were screened by particle agglutination (PA) test were analysed for HTLV-1 DNA by both PCR methods. Of 30 PA-positive specimens, 28 were also positive for HTLV-1 antibody by Western blot (WB) analysis, but two were indeterminate. The twenty eight WB-positive and one of the two indeterminate specimens were positive for HTLV-1 proviral DNA by both PCR methods. Of 23 PA-negative specimens, 22 were negative for HTLV-1 proviral DNA by both PCR methods. However, one PA-negative specimen was positive by both PCR methods. This patient was a 16-mth-old infant who was born to an HTLV-1 carrier mother and fed thereafter without her breast milk. In comparison to DNA extraction-PCR method, the sensitivity and specificity of the filter paper-PCR method was 100%, respectively.

Identification of a type-specific protein that differentiates serologically between human T cell lymphotropic virus types I and II

The 24-kDa band formed when sera of humans infected with human T cell lymphotropic virus type I (HTLV-1) were reacted with HTLV-I lysates in conventional Western blot (WB) assays was found to be composed of two immunologically unrelated proteins of 24- and 23-kDa. p24, but not p23, carries epitopes shared by the major core proteins of the other known transactivating C-type retroviruses. p23 is unrelated immunologically to the env and tax HTLV-I products but partly cross-reacts with HTLV-I p19. All HTLV-I and simian T cell leukemia virus type I sera tested reacted with p23. Reactivity with p23 was seen with some HTLV-I sera that did not react or reacted weakly with HTLV-I p24. No reactivity with p23 was seen among the 51 human HTLV-II sera tested nor among a large panel of control sera. Because of its type-specificity and strong immunogenicity, p23 provides a reliable serologic marker for the diagnosis of HTLV-I infection and for distinguishing between HTLV-I and -II.

Polymerase chain reaction amplified HTLV-I, HIV-1 and HIV-2 DNA fragments in subjects with mixed retroviral infections

Serum and peripheral blood mononuclear cells from eight patients from the Ivory Coast with positive screening test results for retroviral infections were studied by serology (ELISA, Western blot (WB), synthetic peptide test), cell co-culture, and polymerase chain reaction (PCR). Two HIV-2 infections with indeterminate interpretation on HIV-1 WB were detected, two were clear dual HIV-1/HIV-2 infections, three were ambiguous mixed HIV-1/HIV-2 infections, and one was a triple retroviral infection by HTLV-I, HIV-1 and HIV-2. Four slow/low HIV-1 strains were isolated at the expense of HTLV-I and HIV-2 strains. The ELISA tests were found to be very sensitive. Indeterminate WB interpretations were frequent (HTLV-I, four; HIV-1, three; HIV-2, two). PCR provided clear evidence of multiple retroviral infections in three cases and enabled interpretation of indeterminate WB samples in three cases. One sample presented a puzzling pattern with positive PCR results for HIV-1 and HIV-2 associated with negative or indeterminate serological results. Thus, our data emphasise the need to analyse serological as well as virological markers to gain better insight on mixed retroviral infections, especially in endemic areas such as West Africa.

Polymerase chain reaction for diagnosis of infectious diseases

The polymerase chain reaction (PCR) has been utilized and demonstrated to be useful for detecting minute amounts of a wide variety of infectious agents. In such studies, one must keep in mind that the most appropriate conditions for amplification vary with organisms of interest. In this study, PCR was used as a rapid and sensitive method for detecting infectious agents for which three assay systems were devised comprising the method for the amplification of human T cell leukemia virus type I, Mycobacterium tuberculosis and Mycoplasma pneumoniae. The possibility of vertical transmission of human T cell leukemia virus type I through cord blood was demonstrated using cord blood mononuclear cells from carrier mothers of this virus. In the study of Mycobacterium tuberculosis, PCR was shown to be efficient, particularly in detecting this organism in extrapulmonary cases. Evidence of direct invasion into the central nervous system by Mycoplasma pneumoniae and the concomitant occurrence of mycoplasmaemia in the mycoplasmal central nervous system involvement was obtained using PCR. These results validated the potential of PCR in the clinical research of infectious diseases.

Determination of human T lymphotropic virus type by polymerase chain reaction and correlation with risk factors in northern California blood donors

To determine the relative prevalence of human T lymphotropic virus (HTLV) types I and II, type-specific polymerase chain reaction (PCR) was done on seropositive northern California blood donors. From October 1988 through March 1990, 67 (0.055%) of 122,517 blood donors had confirmed HTLV antibody. Seropositive donors were more likely to be middle-aged, female, and nonwhite than the overall donor base. PCR of samples from 30 HTLV-seropositive donors yielded 19 (63%) with HTLV-II and 9 (30%) with HTLV-I; 2 (7%) were repeatedly negative by PCR. HTLV-I-infected subjects had ancestry (n = 3), sexual contact (n = 3), or paternal military service in (n = 1) Japan or the Caribbean. HTLV-II carriers reported past intravenous drug abuse (n = 3) or sex with a drug user (n = 11). Two carriers of each type reported previous blood transfusions, and 1 HTLV-II carrier was a dentist with no other risk factors for retroviral infection.

Tumor viruses in CD30-positive anaplastic large cell lymphomas

CD30+ anaplastic large cell lymphoma (ALCL) represents a novel lymphoma entity at the borderline between Hodgkin's disease and non-Hodgkin's lymphomas. Phenotypic, genotypic, and karyotypic analyses have shown that ALCL are heterogeneous in cellular origin, and may be conceived as malignancies derived from activated, mainly T- or B-lymphoid cells, in some instances with an immature genotype. Epstein-Barr virus genomes and gene products, most notably the transformation-associated latent membrane protein (LMP), have been detected in a proportion of cases, and some cutaneous ALCL proved to harbor complete or incomplete HTLV-1 proviruses. These findings suggest that both EBV and HTLV-I, which are powerful inducers of CD30 expression in lymphoid cells in vitro, may contribute to the pathoetiology of ALCL.

Chronic progressive spinocerebellar syndrome associated with antibodies to human T-lymphotropic virus type I: clinico-virological and magnetic resonance imaging studies

The relationship between HTLV-I infection and the development of spinocerebellar degeneration (SCD) in adulthood was studied. The frequency of anti-HTLV-I antibodies among patients with SCD (8 of 43, 19%) was found to be higher than the seroprevalence rate in the northern part of Kyushu island (6%). All HTLV-I carriers with SCD showed chronic progressive cerebellar ataxia as a predominant feature and cerebellar atrophy was evident in 6 of 8 patients on magnetic resonance imaging (MRI) of the brain. However, SCD patients with anti-HTLV-I antibodies showed a significantly higher frequency of cerebral white matter lesions on brain MRI (6 of 8) and pyramidal tract signs in lower extremities (6 of 8) than did those without the antibodies (35%, P < 0.05 and 26%, P < 0.01, respectively). Moreover, the HTLV-I carriers with SCD exceeded 14 HTLV-I carriers having neither SCD nor HTLV-I-associated myelopathy (HAM)/tropical spastic paraparesis (TSP) (21%, P < 0.05), and 59 HTLV-I seronegative patients without brain disorders (19%, P < 0.001) in the frequency of white matter lesions. On the other hand, the HTLV-I carriers with SCD were distinct to the HAM/TSP patients in the predominance of cerebellar involvement. Therefore, the peculiar features of cerebellar, pyramidal and white matter involvement in the HTLV-I-seropositive SCD patients as well as the increased frequency of HTLV-I infection among SCD patients suggest that this syndrome may be a distinct subtype of HTLV-I-associated neurologic diseases.

Incidence of HTLV-I/II infection in seronegative high-risk individuals

The frequency of human T-cell lymphotropic virus types I and II (HTLV-I/II) polymerase chain reaction (PCR) reactivity was studied in two groups of high-risk individuals in Amsterdam: hard drug users and heterosexual outpatients of the sexual transmitted diseases (STD) clinic. Both groups were seronegative as determined by enzyme-linked immunosorbent assay (ELISA), Western blot (WB), and radioimmuno-precipitation assay (RIPA). Detection of HTLV-I and HTLV-II in peripheral blood mononuclear cells (MNC) was performed by PCR, using primer sets indicative for the pol and tax genes. In the hard drug users group (n = 25) no evidence of HTLV-I/II infection was found whereas in the STD group (n = 21) one individual was identified with HTLV-II proviral DNA. Positive reactions in PCR were confirmed only for three seropositive controls after in vitro culture of MNC but not for the PCR-positive, seronegative individual. Virus production in vitro could not be detected by a sensitive HTLV-I antigen capture assay for viral p24gag proteins after in vitro T-cell stimulation of MNC, either from PCR-positive or PCR-seronegative individuals. This suggests again a low viral production rate. It is concluded that infection with HTLV-II can be detected among high-risk seronegative individuals.

Discrimination of human T-lymphotropic virus type-I and type-II infections by synthetic peptides representing structural epitopes from the envelope glycoproteins

Synthetic peptides representing the immunodominant structural motifs of the envelope region of human T-lymphotropic virus types I (HTLV-I) (Env-1(191-214) and Env-5(242-257)) and II (HTLV-II) (Env-20(85-102 and Env-2(187-209)) were used to develop an enzyme immunoassay that could discriminate between HTLV-I and HTLV-II. Serum specimens from individuals whose infections were confirmed and typed by means of the polymerase chain reaction (PCR) were used to determine the sensitivity and specificity of the new assay. When 73 PCR-confirmed HTLV-I specimens were tested with the HTLV-I peptides, the absorbance values for 71 (97.3%) were at least two times higher than the values obtained with the HTLV-II peptides; these samples thus were classified as HTLV-I. Two specimens reacted with all the peptides and, therefore, could not be typed. Conversely, when 59 PCR-confirmed HTLV-II specimens were tested with the HTLV-II peptides, 55 (93%) produced high absorbance values and were typed as HTLV-II; 4 specimens could not be typed. None of the specimens was incorrectly typed; hence, the specificity of this assay was 100%. When this assay was compared with other HTLV immunoassays, the degrees of sensitivity and specificity were similar. The main advantage of this new assay is that synthetic peptides representing variant sequences can easily be added as new variant HTLV strains are identified.

Combined treatments with interferon (alpha,beta) plus PGA1 to control early infection with HTLV-I in primary cord blood-derived mononuclear cells

Interferon (IFN) alpha and beta can activate an antiviral and immunomodulating response in primary cord blood-derived mononuclear cells (CBMC) exposed to infection with Human T-cell Leukemia Virus type I (HTLV-I), resulting in partial inhibition of early infection in vitro. On the other hand, PGA1, a PGE1-derived cyclopentenone prostaglandin, can inhibit in vitro the proliferation of virus-infected CBMC, preventing the emergence of the potentially transformed clone. In order to achieve a complete control of HTLV-I infection in this experimental model, we evaluated whether the antiviral activity of IFNs and the antiproliferative activity of PGA1 could be preserved in a combination therapy scheme. Recipient CBMC were treated with IFN alpha or beta (1000 IU/ml) at the onset of the co-culture with lethally irradiated virus-donor MT-2 cells, followed by multiple treatments with PGA1 (4 micrograms/ml every 4 days, starting on day 0) for 6 weeks post infection (p.i.). In PGA1-treated co-cultures the percentage of virus-positive CBMC was constantly doubled during culture time as well as the amount of viral transcripts and p19 virus core protein production were increased. The antiviral effects of IFNs, resulting in about a 50% reduction of the percentage of virus-positive CBMC and consequently in a partial inhibition of virus expression (HTLV-I transcription and p19 production) until 4 weeks p.i., were suppressed by multiple PGA1 treatments. However, the antiproliferative effect of PGA1 was enforced in IFN-treated co-cultures, leading to earlier control of proliferation of virus-infected cells. Interestingly, infection of CBMC with HTLV-I was associated with persistent expression of 70 kDa heat shock protein (HSP70), for at least 4 weeks p.i. IFNs and PGA1 showed antagonistic effects on HSP70 production in infected CBMC. In fact, production of HSP70 was suppressed (or prevented) in IFN-treated co-cultures, tested 2 and 4 weeks p.i. The fact that the expression of HSP70 is apparently suppressed (or prevented) by IFN treatment is surprising, since expression of this protein family has been associated with antiviral immunity. PGA1 could totally reverse the IFN-mediated suppression of HSP70 expression in these co-cultures. It is presently unclear whether HSP70 expression is directly involved in the control of proliferation exerted by PGA1 against virus-infected CBMC or is an epiphenomenon associated with inhibition of cell growth.

HTLV-1 sequences in lymphocytes of a patient with non-tropical spastic tetraparesis and her asymptomatic husband

We describe a 65-year-old woman born and living in Northern Italy affected by non tropical spastic tetraparesis and her asymptomatic husband presenting HTLV-1 sequences in their lymphocytes detected by polymerase chain reaction (PCR). We discuss the significance of the case and the mechanism involved in HTLV-1 infection and the relationship with neurological disorders, stressing that this case is the first reported in Italy.