HTLV-I and HTLV-II world-wide distribution: reanalysis of 4,832 immunoblot results

Epidemiology and Etiopathology of Human T-Lymphotropic Viruses: Diagnostic and Clinical Implications for Non-Endemic Areas

Human T-lymphotropic viruses (HTLV) type I and II were first described more than a decade ago. HTLV-I epidemiology and etiopathology are more defined than those of HTLV-II, but conflicting results have been obtained in seroepidemiologic surveys, mainly for difficulties in the discrimination between the two infections. The introduction of advanced serologic and molecular assays has recently provided sensitive and specific tools for diagnosis, and the epidemiologic and etiopathologic patterns linked to these retroviruses are being more precisely defined. Moreover, extensive nucleotide sequence analyses performed so far have mainly focused on HTLV-I isolates. The recent discovery of new HTLV-II endemic areas and the isolation of HTLV-II strains from intravenous drug users have finally provided the material for the molecular characterization of HTLV-II isolates, which is now a rapidly envolving field. We review the diagnostic strategies available and the etiologic associations reported so far for both viruses and also discuss the occurrence and significance of indeterminate serologic reactivities observed in both endemic and non-endemic areas.

Human T-lymphotropic virus 1aA circulation and risk factors for sexually transmitted infections in an Amazon geographic area with lowest human development index (Marajó Island, Northern Brazil)

BACKGROUND

This cross-sectional study evaluated the prevalence of infection with human T-lymphotropic virus 1 and 2 (HTLV-1 and HTLV-2) in a population from the municipalities of Anajás, Chaves, São Sebastião da Boa Vista (SSBV) and Portel in the Marajó Archipelago and correlated these data with the epidemiological characteristics of the study population.

METHODS

A total of 1899 biological samples were evaluated. The samples were screened for the presence of anti-HTLV antibodies using an enzyme-linked immunosorbent assay (ELISA), and infection was confirmed using conventional polymerase chain reaction (PCR), real-time PCR and nucleotide sequencing.

RESULTS

Eleven samples (0.58%) were seropositive for HTLV, but molecular analysis confirmed positivity in only two samples (0.11%). Nucleotide sequencing and phylogenetic analysis indicated that the two samples positive for HTLV-1 that were isolated in Chaves belonged to the Cosmopolitan subtype 1 (HTLV-1a) and Transcontinental subgroup (A).

CONCLUSION

Our results confirmed the presence of Cosmopolitan Transcontinental HTLV-1 in the Marajó Archipelago, Amazon region, and the majority of the population revealed a lack of knowledge about sexually transmitted infections, which increases the risk of dissemination of HTLV and other agents.

Relative frequency of Human T-cell Lymphotropic Virus I/II in HIV/AIDS patients

Background:

Human T-cell lymphotropic virus HTLV-I/II is a retrovirus that has been associated with different diseases. HTLV-I/II routes of transmissions are exposure to contaminated blood, blood transfusion, needle sharing, breast feeding, and sexual contact. The seroprevalence of HTLV-I/II in HIV infected patients has not been well characterized in Iran. We conducted a serological survey to determine the relative frequency of HTLV-I/II in HIV+/AIDS and healthy blood donors in Isfahan.

Materials and Methods:

In this cross-sectional study, we compare the relative frequency of HTLV-I/II in HIV+/AIDS group (56 persons) with asymptomatic blood donors (57 persons) in Isfahan. Participant completed the questionnaires that include demographic information, age, sex, and sexual partnership during last 6 months, sexual behavior and past history of blood transfusion or other blood products. We confirm the HIV+ status in patients group with western blot test. Evaluation of HTLV-I/II were done using ELISA test with DRAPIO third generation kit. Questionnaire data and laboratory results were analyzed by SPSS18.

Results:

During the period of 2010-2011, a total of 56 HIV-infected patients and 57 healthy persons participated in this study. Among HIV positive patients, one person had positive test for HTILV-I/II representing the relative frequency of 1.8%, and in healthy individuals none of them were positive.

Conclusion:

In our survey, relative frequency of HTLV-I/II was 1.8% in HIV+ patients. This study reveals that relative frequency of HTLV-I/II in HIV positive patients is considerable but determining the need for screening of HTLV-I/II requires further investigation.

Epidemiological analysis of HTLV-1 and HTLV-2 infection among different population in Central China

Background

HTLV-1 and HTLV-2 are retroviruses linked etiologically to various human diseases, and both of them can be transmitted by vertical route, sexual intercourse, blood transfusion and intravenous drug use. Recently, some HTLV-infected cases have been reported and this virus is mainly present in the Southeast coastal areas in China, but has not been studied for the people in Central China.

Objectives

To know the epidemiologic patterns among different population samples in Central China and further identify risk factor for HTLV-1 and HTLV-2 infection.

Methods

From January 2008 to December 2011, 5480 blood samples were screened for HTLV-1/2 antibodies by using enzyme immunoassay, followed by Western Blot.

Results

The prevalence of HTLV-1 and HTLV-2 was found with infection rates 0.13% and 0.05% among all population samples for HTLV-1 and HTLV-2, respectively. The highest percentages of infection, 0.39% and 0.20%, were found in the high risk group, while only 0.06% and 0.03% in the blood donor group. There was only one case of HTLV-1 infection (0.11%) among patients with malignant hematological diseases. Of seven HTLV-1 positive cases, six were co-infected with HBV, two with HCV and one with HIV. Among three HTLV-2 positive individuals all were co-infected with HBV, one with HCV.

Conclusions

HTLV-1 and HTLV-2 have been detected in the Central China at low prevalence, with the higher infection rate among high risk group. It was also found that co-infection of HTLV-1/2 with HIV and HBV occurred, presumably due to their similar transmission routes. HTLV-1/2 antibody screen among certain population would be important to prevent the spread of the viruses.

HTLV infection among foreign pregnant women living in Spain

BACKGROUND

The overall seroprevalence of HTLV infection among pregnant women in Spain is below 0.02% and accordingly universal antenatal screening is not recommended. However, as the number of immigrants has significantly increased during the last decade, this population might warrant specific considerations.

OBJECTIVE

To evaluate the seroprevalence of HTLV infection among immigrant pregnant women living in Spain.

METHODS

From January 2009 to December 2010 a cross-sectional study was carried out in all foreign pregnant women attended at 14 Spanish clinics. All were tested for HTLV antibodies using a commercial enzyme-immunoassay, being reactive samples confirmed by Western blot or PCR.

RESULTS

A total of 3337 foreign pregnant women were examined. Their origin was as follows: Latin America 1579 (47%), North Africa 507 (16%), East Europe 606 (18%), Sub-Saharan Africa 316 (9%), North America and West Europe 116 (3.5%) and Asia and Australia 163 (5%). A total of 7 samples were confirmed as HTLV positive, of which 6 were HTLV-1 and 1 HTLV-2. HTLV-1 infection was found in 5 women coming from Latin America and 1 from Morocco. The only woman with HTLV-2 came from Ghana. The overall HTLV seroprevalence was 0.2%, being 0.3% among Latin Americans and 0.2% among Africans. It was absent among women coming from other regions.

CONCLUSIONS

The seroprevalence of HTLV infection among foreign pregnant women in Spain is 0.2%, being all cases found in immigrants from Latin America and Africa. Given the benefit of preventing vertical transmission, antenatal screening should be recommended in pregnant women coming from these regions.

Seroprevalence of HTLV-1/2 infection among native and immigrant pregnant women in Spain

HTLV-1=2 antenatal screening is not mandatory in European countries. The rapid increase in immigrants coming from areas endemic for HTLV-1 infection has compelled a review of this policy in Spain. From February 2006 to December 2007, a cross-sectional study was carried out in all pregnant women attended at 10 different Spanish hospitals. An enzyme immunoassay (EIA) was used to test serum HTLV-1=2 antibodies; reactive samples were further confirmed by Western blot and=or polymerase chain reaction. A total of 20,518 pregnant women were examined, of whom 18,266 (89%) were native Spaniards. Overall, 946 (4.6%) of the immigrants came from HTLV-1 endemic areas (mainly Central and South America and sub-Saharan Africa). Four samples were EIA seroreactive for HTLV-1=2, two of them in women infected with HTLV-1 coming from endemic areas. The other two women were infected with HTLV-2; one was an immigrant from Bolivia and another was a native Spaniard who admitted prior injection drug use and was HIV-1 positive. The overall HTLV-1=2 seroprevalence was 0.19 per 1000 (95% CI: 0.05-0.49=1000). For HTLV-1, the seroprevalence was 2.11 per 1000 (95% CI: 0.26-7.62=1000) in pregnant women from endemic areas. The seroprevalence of HTLV-1=2 infection is below 0.02% among pregnant women in Spain, and therefore universal screening for HTLV-1=2 infection in antenatal clinics is not warranted. However, HTLV-1=2 screening could be considered in pregnant women coming from endemic areas, in whom the rate of infection is nearly 1000-fold higher than in native Spaniards and are the only group infected with the more pathogenic HTLV-1.

Subacute progression of human T-lymphotropic virus type I-associated myelopathy/tropical spastic paraparesis

Although human T-lymphotropic virus type I (HTLV-I)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is usually described as a chronic disabling disease, a rapid course over months or even weeks has been reported in some patients. The authors describe the clinical features of HAM/TSP in a Brazilian cohort and evaluate the prevalence of patients with a subacute progression of the disease. This was defined as the requirement of a wheelchair during the first 2 years after the onset of symptoms. Patients with this subacute course and patients with the chronic clinical course were compared in terms of their HTLV-I proviral loads (PLs) using real-time polymerase chain reaction (PCR). Seven out of 88 patients (7.9%) had a subacute progression. All patients were women and 5/7 acquired HTLV-I through sexual contact. There was no significant difference in the real-time PLs between the group with subacute evolution (mean 8.5 copies/100 cells, range 6.03 to 12.09) and those patients with a typical course of disease (mean 11.34 copies/100 cells, range 0.4 to 67.72) (P = .68), suggesting that factors other than the number of infected cells are implicated in the development of such an aggressive course of disease. Early recognition of this subgroup is important because immunosuppressive treatment might be beneficial if instituted promptly.

[HTLV-1 and HTLV-2 proviral load: a simple method using quantitative real-time PCR]

When the human T cell lymphotropic virus (HTLV) is integrated with the host cell genome (provirus), its proviral DNA is a replication marker. Proviral load appears to be an important factor in the development of diseases related to these retroviruses. In this study, a methodology for absolute quantification of the HTLV-1 and HTLV-2 proviral load using real-time PCR was developed. Fifty-three blood donor samples with positive ELISA test result were subjected to this methodology, which utilized the TaqMan system for three target sequences: HTLV-1, HTLV-2 and albumin. The absolute proviral load was quantified using the relative ratio between the HTLV genome and the host cell genome, taking into consideration the white blood cell count. The method presented is sensitive (215 copies/ml), practical and simple for proviral quantification, and is efficient and appropriate for confirming and discriminating infections according to viral type.

Epidemiological survey of intraocular inflammation in Japan

PURPOSE

To report the frequency and trend of intraocular inflammation based on a survey of new ophthalmology patient visits to university hospitals throughout Japan during 2002.

METHODS

A questionnaire was sent to the departments of ophthalmology in 110 university hospitals nationwide to survey the total number of new patients who visited the outpatient clinics for the first time between 1 January and 31 December 2002, and also the number of patients diagnosed with intraocular inflammation during this period.

RESULTS

The surveys completed by 41 university hospitals were analyzed in this study. During 2002, a total of 151 299 new ophthalmological patients presented at the 41 institutions, and 3060 (2.2%) of the new patients were diagnosed as having intraocular inflammation. The most frequent intraocular inflammatory disease identified was sarcoidosis (13.3%), followed by Vogt-Koyanagi-Harada (VKH) disease (6.7%), Behçet disease (6.2%), bacterial endophthalmitis (3.8%), herpetic iridocyclitis (3.6%), diabetic iritis (1.6%), human leukocyte antigen-B27-associated uveitis (1.5%), acute retinal necrosis (1.3%), ocular toxoplasmosis (1.1%), ocular toxocariasis (1.1%), uveitis associated with human T lymphotropic virus-1 (also known as HAU) (1.1%), and others. Infectious intraocular inflammation accounted for 16% of all uveitis cases.

CONCLUSIONS

Through the collaboration of a large number of institutions, some aspects of the epidemiology of intraocular inflammation in Japan were elucidated. However, the disease concept and diagnostic criteria remain ambiguous for a considerable number of diseases within the spectrum of intraocular inflammation, and the possibility that such factors may bias the present findings cannot be denied. In the future, a prospective survey based on well-defined, common diagnostic criteria is required to obtain more precise epidemiological data.

Peripheral blood mononuclear cells from individuals infected with human T-cell lymphotropic virus type 1 have a reduced capacity to respond to recall antigens

Evidence indicates that human T-cell lymphotropic virus type 1 (HTLV-1) infection leads to chronic immunosuppression and a greater susceptibility to infectious diseases. Spontaneous in vitro proliferation of peripheral blood mononuclear cells (PBMC) is an important immunological feature of HTLV-1-infected individuals. However, the association between spontaneous proliferation and immunosuppression is not clear. In this study, we evaluated the cellular immune responses of PBMC from 58 asymptomatic HTLV-1-infected individuals with PBMC showing or not showing spontaneous proliferation. Individuals with PBMC that spontaneously proliferated had increased proportions of CD4 T cells expressing CD45RO and dramatically reduced responses to recall antigens. In addition, frequencies of positive responses to recall antigens were also decreased in HTLV-infected individuals without spontaneous proliferation of PBMC. There was a polyclonal expansion of multiple T-cell receptor Vbeta families of CD4+ T lymphocytes in patients with spontaneous proliferation. We observed that HTLV-1 induced an immunosuppression characterized by a decrease in the stimulation index to a recall antigen, even in individuals who did not present spontaneous proliferation. On the other hand, only patients with PBMC presenting spontaneous proliferation showed polyclonal activation and increased proportion of CD4 T cells expressing CD45RO.

[Dermatologic lesions in patients infected with the human T-cell lymphotropic virus type 1 (HTLV-1)]

Human T-cell Lymphotropic virus type I (HTLV-1) was the first human retrovirus described. Some time after its discovery a group of diseases were related to this virus, such as, adult T-cell leukemia lymphoma (ATLL), HTLV-1 associated myelopathy/tropical spastic paraparesis (HAM/TSP) and HTLV-1 associated uveitis (HAU). In the nineties, HTLV-1 was associated to a severe eczema of children, called infective dermatitis (ID). Since then, several other skin manifestations have been observed in HTLV-1-infected individuals, particularly in patients with ATLL or HAM/TSP. However, according to some reports, dermatologic lesions are also common in asymptomatic HTLV-1 carriers. Besides ID, all other skin lesions reported are nonspecific. The aim of this review is to outline the dermatologic manifestations reported in HTLV-1 infected patients, emphasizing the clinical and epidemiological value of these findings.

Prevalência da infecção pelo vírus linfotrópico humano de células T e fatores de risco associados à soropositividade em doadores de sangue da cidade de Rio Branco, AC, Brasil (1998-2001)

Para cada doador de sangue soropositivo (ELISA, Abbott®) para HTLV-I/II, de dezembro de 1998 a março de 2001, também foram selecionados dois soronegativos. As amostras séricas foram re-testadas pelo ELISA (Murex®) e aquelas que permaneceram soropositivas foram testadas pelo Western Blot e pela PCR. Das 11.121 amostras séricas, 73 (0,66%) foram positivas (Abbott®), mas somente 12 (0,11%) permaneceram positivas (Murex®), enquanto que as 146 soronegativas foram confirmadas, apesar de ser sofrível o índice de concordância entre os dois ELISA. O Western Blot confirmou as 12 amostras como soropositivas: 8 (0,07%) HTLV-I; duas (0,02%) HTLV-II e duas (0,02%) indeterminadas - sendo pela PCR uma pelo HTLV-I e a outra pelo HTLV-II. Em conclusão, nessa população da Amazônia Ocidental foi muito baixa a soroprevalência de HTLV-I/II, apesar de ser esperada maior prevalência do HTLV-II devido a grande miscigenação racial indígena.

Detection of human T-lymphotropic virus (HTLV) tax sequences in New York City blood donors seronegative for HTLV types 1 and 2

A potential public health concern is the reported detection of the human T-lymphotropic virus (HTLV) tax gene in the lymphocytes of up to 11% of a low-risk group of New York City blood donors (NYBD). This study aimed to independently confirm the prevalence of HTLV tax sequences in 293 NYBD. All NYBD tested negative for antibodies to HTLV types 1 and 2 and HTLV Tax. HTLV tax sequences were not detected in the NYBD lymphocytes. These data demonstrate the lack of HTLV-1 tax in this group of NYBD at low risk for HTLV infection.

Advances in interleukin 2 receptor targeted treatment

T cell activation and cellular immune responses are modulated by interleukin 2 (IL2) through binding to its corresponding cell surface receptor. Three forms of the receptor are recognised based on IL2 binding affinity. The high affinity receptor is a heterotrimer composed of alpha, beta, and gamma(c)-polypeptide chains. The 55 kDa alpha-chain also known as the Tac (T cell activation) antigen or CD-25 is a unique subunit of the high affinity IL2 receptor (IL2Ralpha). Resting T cells express few IL2Ralpha, however, when activated, the expression of ILR2alpha rapidly increases. The IL2Ralpha is shed from the cell surface and is measurable in the serum as a 45 kDa soluble form (s-Tac or s-IL2Ralpha). Serum concentrations of s-Tac can be used as a surrogate marker for T cell activation and IL2Ralpha expression. IL2Ralpha is over expressed by T cells in a number of autoimmune diseases, allograft rejection and a variety of lymphoid neoplasms. IL2 induced proliferation of T cells can be inhibited by the murine monoclonal antibody (anti-Tac) directed against the alpha-chain of the IL2R. Through molecular engineering, murine anti-Tac has been humanised reducing its immunogenicity without changing its specificity. Humanised anti-Tac (HAT) has been shown to reduce the incidence of renal and cardiac allograft rejection as well as decrease the severity of graft versus host disease in patients undergoing HLA matched allogeneic bone marrow transplantation. IL2Ralpha targeted treatment with radioimmunoconjugates of anti-Tac and immunotoxins has shown promise in the treatment of CD25 expressing lymphomas.

Human T-lymphotropic virus type I infection

Human T-cell lymphotropic virus type I (HTLV-I) is the first human retrovirus to be associated with malignant disease--namely, adult T-cell leukaemia/lymphoma. HTLV-I has also been associated with several non-malignant conditions, notably the chronic neurodegenerative disorder, HTLV-I associated myelopathy (also known as tropical spastic paraparesis), infective dermatitis of children and uveitis. More recent evidence points to disease associations not previously linked to HTLV-I. Thus, the disease spectrum of HTLV-I is not fully known. HTLV-I has a worldwide distribution with major endemic foci in the Caribbean and southern Japan. The public health importance is confirmed by the major routes of transmission, which are mother-to-child, blood transfusion, and sexual activity. Unfortunately, no vaccine is available yet and there is no proven treatment for advanced HTLV-I disease.

Assessment of a new immunoassay for serological confirmation and discrimination of human T-cell lymphotropic virus infections

The present study evaluated a new confirmatory assay for antibodies to human T-cell lymphotropic virus type 1 and 2 (HTLV-1 and HTLV-2) proteins performed with serum samples from various commercial sources. The new test is a line immunoassay (LIA) with a nylon membrane sensitized with the most relevant antigens of HTLVs: the envelope gp46 and gp21 as well as the gag p24 and p19 antigens, represented by either recombinant proteins or synthetic peptides. A total of 176 serum or plasma samples were tested, of which 66 were HTLV-1 positive, 72 were HTLV-2 positive, and 38 were HTLV negative; of the 38 HTLV-negative samples 23 were indeterminate by Western blotting (WB). Serially diluted samples (n = 33) from HTLV-1- and HTLV-2-infected patients were also analyzed to determine the sensitivity of the new assay. The new confirmatory assay (INNO-LIA HTLV) performed markedly better than WB assays for those samples reactive by screening. Accurate confirmation of the presence of HTLV-1 and HTLV-2 antibodies and accurate discrimination of HTLV-1 and HTLV-2 antibodies were obtained for all the HTLV-seropositive samples. Due to its enhanced specificity and sensitivity, the new assay not only improves the ability to confirm and discriminate HTLV infections but also eliminates the vast majority of WB-indeterminate and false-positive specimens.

Evaluation of a new HTLV-I/II polymerase chain reaction

AIM

Evaluation of a qualitative HTLV-I/II DNA polymerase chain reaction (PCR) test for the detection of HTLV-I/II DNA (Roche Diagnostic Systems, Branchburg, N.J., USA) in various panels.

METHODS

The panels consisted of fresh EDTA blood samples from blood donors who were anti-HTLV-I/II ELISA repeatably reactive: 53 were Western blot (WB) positive, 228 were WB indeterminate and 15 were WB negative. Elevent ELISA-negative blood donors were used as negative controls. Furthermore, specimens from 1 HTLV-II-infected intravenous drug user and from 1 HTLV-II-infected blood donor were included in the panel. Peripheral blood lymphocytes were prepared by red blood cell lysis with the Roche washing solution and stored at < -23 degrees C until processing. Amplification products were analyzed with the HTLV-I/II detection kit.

RESULTS

All 53 anti-HTLV-I/II ELISA- and WB-positive samples and both HTLV-II-positive samples tested positively by PCR. All 228 anti-HTLV-I/II ELISA-positive and WB-indeterminate, all 15 ELISA-positive and WB-negative and all II ELISA-negative control samples tested negative by PCR.

CONCLUSION

The Roche Amplicor HTLV-I/II test is a simple test, suitable for the confirmation of HTLV-I and-II infection in individuals with indeterminate or positive WB patterns.