Surveillance of human retroviruses in blood samples from patients with hepatitis B and C in São Paulo, Brazil

INTRODUCTION

Human retroviruses and the hepatitis B and C viruses (HBV and HCV, respectively) share routes of transmission; thus, coinfections occur and could alter subsequent disease outcomes. A preliminary study on human T-lymphotropic virus types 1 and 2 (HTLV-1/2) in serum samples from HBV- and HCV-infected individuals in São Paulo revealed 1.3% and 5.3% rates of coinfection, respectively. These percentages were of concern since they were detected in HTLV-endemic regions and in high-risk individuals in Brazil. The present study was conducted to extend and confirm these data.

METHODS

HTLV-1/2 and human immunodeficiency virus (HIV) infection status were identified in 1,984 sera for HBV and HCV viral load quantification - 1,290 samples from HBV-infected individuals (53.3% men, mean age: 47.1 years) and 694 samples from HCV-infected individuals (56.3% men, mean age: 50.1 years). HTLV-1/2 antibodies were detected by enzyme immunoassay, followed by western blotting and line immunoassay; HIV infection was detected by enzyme immunoassay.

RESULTS

HTLV-1/-2 infection was detected in 1.9% HBV-infected individuals (0.7% HTLV-1 and 1.2% HTLV-2) and in 4.0% (2.4% HTLV-1 and 1.6% HTLV-2) HCV-infected individuals; HIV infection was detected in 9.2% and 14.5%, respectively. Strong associations with HTLV and HIV, male sex, and older age were found in HBV/HTLV and HCV/HTLV-coinfected individuals (p<0.05).

CONCLUSIONS

HTLV-1 and HTLV-2 were confirmed to be prevalent in individuals with HBV and HCV in São Paulo; coinfected individuals deserve further clinical and laboratory investigation.

The prevalence and significance of HTLV-I/II seroindeterminate Western blot patterns

Human T-lymphotropic virus type I (HTLV-I) infects an estimated 15–20 million persons worldwide. A number of diseases have been associated with the virus including adult T-cell leukemia (ATL), HTLV-associated myelopathy/tropical spastic paraparesis (HAM/TSP), HTLV-I uveitis, and HTLV-I-associated infective dermatitis. Once it was shown that there is an increased risk for developing HAM/TSP associated with blood transfusion, screening for HTLV-1 among blood banks was implemented in Japan, United States, France, and the Netherlands. This process includes detection by an enzyme immunoassay (EIA) followed by a confirmatory Western blot (WB) in which recombinant proteins specific for HTLV-I Env glycoproteins are incorporated into WB strips. HTLV-I seropositive results are defined by the presence of antibodies against either gp46 or gp62/68 (both Env protein bands) and either p19, p24, or p53 (one of the gag bands). HTLV-II seropositivity is confirmed by the presence of rgp46-II. However, numerous cases have been documented in which serum samples are reactive by EIA, but an incomplete banding pattern is displayed by subsequent confirmatory WB. Although the significance of these HTLV-I/II seroindeterminates is unclear, it may suggest a much higher incidence of exposure to HTLV-I/II than previously estimated.

[Investigation of anti-HTLV I/II seroprevalence in healthy blood donors in Izmir region, Turkey]

Almost 10-20 million people in the world are thought to be infected by human deltaretroviruses, namely human T-cell lymphotropic virus (HTLV) type I and II, recently. HTLV-I is endemic in southwestern Japan, the Caribbean and sub-Saharan Africa, whereas HTLV-II is more prevalent in intravenous drug addicts, and in American indian populations, endemically. HTLV-I is mainly responsible for adult T-cell leukemia (ATL) and HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP), however, HTLVII is not clearly associated with a known clinical disease. Both viruses may be transmitted by sexual contact, parenteral route, whole blood transfusion and breast-feeding. In most of the countries [USA, Canada, South America, Caribbean, Japan, Taiwan and some Europe countries (France, UK, Ireland, Sweden, Denmark, The Netherlands, Portugal, Romania, Greece)] routine screening of anti-HTLV-I/II in blood donors is mandatory, however, there is no such practice in Turkey since seroepidemiologic data on HTLVI/II infections is insufficient. In this study, the seroprevalence of HTLV-I/II in healthy blood donors admitted to the blood bank of Ege University Medical Faculty Hospital, Izmir (located at Aegean region), was investigated to support data on the decision making process on routine screening of anti-HTLV-I/II in blood centers. Serum samples from 10.000 healthy blood donors (mean age: 32.6 years; 87.8% were male), who succeeded the donor history questionnaire, were included to the study, and HTLV-I/II antibodies were screened by a commercial enzyme immunoassay (ELISA) (Murex HTLVI-II, Murex Diagnostics, UK) method. Serum samples which were yielded reactive and borderline results were retested by ELISA, and repeated reactive/borderline results were then confirmed by HTLV-I/II confirmation test (INNO-LIA HTLV-I/II, Innogenetics, Belgium). Seven samples yielded reactive/borderline reactive results by both ELISA lots, however, all of them were found negative by confirmatory test. According to our data HTLV-I/II infections are not endemic in Izmir region, and anti-HTLV-I/II screening of blood donors is not required in our blood center currently. Nevertheless, screening HIV which is very rare in prevalence among the donor population, is mandatory for blood donors in our country. Thus, even its prevalence is very low, much more comprehensive and multi-centered studies are necessary for making the decision of integrating HTLV-I/II in routine blood bank screening tests in Turkey.

Difficulties in the diagnosis of HTLV-2 infection in HIV/AIDS patients from Brazil: comparative performances of serologic and molecular assays, and detection of HTLV-2b subtype

The current diagnosis of human T-lymphotropic virus type-2 (HTLV-2) infection is based on the search of specific antibodies; nevertheless, several studies conducted in Brazil pointed deficiencies of the commercially available kits in detecting HTLV-2, mostly in HIV/AIDS patients. This study searched for the presence of HTLV-1 and -2 in 758 HIV/AIDS patients from Londrina, Paraná, Brazil. Serum samples were screened for HTLV-1/2 antibodies using two EIA kits (Vironostika and Murex), and confirmed by WB (HTLV Blot 2.4, Genelabs). The results obtained by EIA disclosed 49 (6.5%) reactive sera: 43 positive by both EIA kits, and six with discordant results. WB confirmed HTLV-1 infection in seven samples (0.9%) and HTLV-2 in 21 sera (2.8%). Negative and indeterminate results were detected in four (0.5%) and 16 (2.1%) sera, respectively. Blood from 47 out of 49 HTLV seroreactive patients were collected and analyzed for the presence of env, LTR and tax genomic segments of HTLVs by PCR. PCR confirmed six cases of HTLV-1 and 37 cases of HTLV-2 infection (14 out of 16 that were found to be WB indeterminate). Restriction analysis of the env PCR products of HTLV-2 disclosed 36 isolates of HTLV-2a/c subtype, and one of HTLV-2b subtype. These results emphasize the need of improving serologic tests for detecting truly HTLV-2 infected patients from Brazil, and confirm the presence of HTLV-2b subtype in the South of this country.

Hospital-based surveillance for HTLV-1/2 infections in Spain

In Western countries, HTLV-1 infection is recognized mainly among foreigners coming from endemic areas. In contrast, HTLV-2 is found predominantly in native intravenous drug users (IDUs). Spain has experienced a large wave of immigration, which could have influenced the current prevalence and distribution of HTLV-1 and HTLV-2 infection. A 1-day cross-sectional survey was carried out in May 2005 in 13 hospitals distributed across Spain. A total of 2873 outpatient subjects were screened for HTLV-1/2 antibodies. Although the majority of the study population consisted of native Spaniards, 206 (7.2%) were immigrants. Two cases of HTLV-1 and one of HTLV-2 infection were found (overall prevalence, 0.1%). The two individuals with HTLV-1 were immigrants from endemic areas and the single case of HTLV-2 infection was a former Spaniard IDU coinfected with HIV-1. In summary, the current prevalence of HTLV-1/2 infection in Spain is low, with no evidence of spread beyond the classical risk groups. However, a rapidly growing population of immigrants from HTLV-1-endemic areas in Spain could modify this pattern and periodic surveillance studies including both natives and immigrants are warranted.

High seroprevalence of anti-HTLV-I/II antibodies among solid organ donors necessitates confirmatory testing

BACKGROUND

Human T-cell lymphotrophic virus (HTLV) type I has been linked to adult T-cell leukemia/lymphoma (ATL) and HTLV-I associated myelopathy (HAM). Transmission of HTLV by blood and organ transplantation has been documented, with some infections leading to clinical disease. Organ donors are tested for anti-HTLV antibodies and donor suitability is determined primarily by results from enzyme immunoassays (EIA). Confirmatory testing is not routinely performed, and the number of false positive organ donors is unknown.

METHODS

In order to investigate the contemporary seroprevalence of anti-HTLV I/II antibodies among solid organ donors and determine the number of false positive samples, we tested 1,408 specimens from prospective organ donors in 2002 and 2003. All specimens were tested for anti-HTLV antibodies by a commercial EIA. Repeatedly reactive specimens underwent confirmatory testing using a commercial Western blot.

RESULTS

There were 22 repeatedly EIA reactive donor specimens (1.56%). Five specimens did not undergo further testing because of case shutdown or insufficient sample quantity. HTLV I/II western blot confirmed six positives, whereas five were negative and six were indeterminate. The majority of confirmed specimens were positive for antibodies to HTLV-II.

CONCLUSIONS

Our data shows that 29% of initially reactive specimens were false positives. With the increasing demand for organs, the unnecessary rejection of organs that are falsely positive for HTLV antibodies becomes of tremendous importance and stresses the need for timely confirmatory testing for HTLV.

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.

Molecular evidence for infection by HTLV-2 among individuals with negative serological screening tests for HTLV antibodies

Previous serological studies on the Arara do Laranjal Indian group revealed extensive HTLV-2 infections. A collection of 97 new samples from the Arara were found repeatedly negative using three different commercial enzyme immunoassays. Eight samples that exhibited optical density readings close to the cut-off value were re-evaluated using Western blot (GeneLab 2.4, Singapore) assay. One sample was found to be non-reactive, five exhibited indeterminate patterns, one was classified as HTLV, and one was confirmed as HTLV-2. Peripheral blood mononuclear cell DNA of the eight samples were subjected to nested PCR and restriction fragment length polymorphism (RFLP) analysis of the pX and env regions, and nucleotide sequencing of the 5'-LTR region. All produced amplification products of pX, but env could be amplified in only one sample with the commonly used primers. RFLP analysis of the pX region using TaqI confirmed HTLV-2 infection. Nucleotide sequencing of the 5'-LTR region was performed in three samples (HTLV-2, HTLV and indeterminate based on Western blot pattern). Phylogenetic analysis of a 449-nt fragment using the Neighbour-Joining method clearly demonstrated that the three samples clustered within the HTLV-2c molecular subtype. The present study confirms the wide dissemination of the HTLV-2c subtype among linguistically and culturally distinct Amazonian Indian groups, and emphasizes the unique occurrence of infection by this subtype in Brazil. Moreover, it emphasizes the limitation of employing the present serological screening assays in blood banks, epidemiological studies, and the importance of molecular assays in the confirmatory procedures for the primary detection of HTLV-2 infections.

Effectiveness of human T-lymphotropic virus (HTLV) recipient tracing (lookback) and the current HTLV-I and -II confirmatory algorithm, 1999 to 2004

BACKGROUND

This study reports on the efficacy of an investigational human T-lymphotropic virus (HTLV)-I and -II lookback program in the context of differing confirmatory testing algorithms.

STUDY DESIGN AND METHODS

The results of testing approximately 35 million donations for anti-HTLV-I and -II were evaluated for two recent periods reflecting the use of two different confirmatory algorithms. The number of seroconverting donors was established for the entire period, and the results of lookback on their prior donations were investigated.

RESULTS

The dual enzyme immunoassay (EIA) strategy was used throughout both study periods and resulted in a 57 to 76 percent reduction in the number of samples requiring confirmatory testing. From May 2000 to February 2002, a total of 9138 samples were repeatedly reactive by the primary screening test; of the concordant EIA-reactive samples, 461 (12%) were confirmed by Western blot, whereas 3083 (79%) were indeterminate. From March 2002 to December 2004, a total of 21,291 samples were repeatedly reactive; of the concordant EIA-reactive samples, 1099 (22%) were confirmed by the State of California's reference laboratory and only 273 (5%) were equivocal. Overall, 38 or 1 in 921,000 donations were from a seroconverting donor with 32 prior donations within the lookback period. Of those 32, components from only 11 were transfused to recipients who survived; of these, 4 were tested and all were nonreactive for HTLV-I and -II antibodies.

CONCLUSION

Use of creative algorithms can increase the efficacy of anti-HTLV-I and -II confirmatory testing and reduce the number of indeterminate results. Currently, lookback for HTLV-I and -II has a very low yield, and its public health benefit is questionable.

HTLV infection among young injection and non-injection heroin users in Spain: Prevalence and correlates

BACKGROUND

Although some studies have described the epidemiology of infection with HIV or hepatitis B and C in young users in Spain - one of the European countries with the highest prevalences - there are no studies of the prevalence of HTLV infection and the most important associated factors.

OBJECTIVES

To evaluate the prevalence and main determinants of HTLV-1 and HTLV-2 infection in young heroin users (including both injection (IDUs) and non-injection drug users (NIDUs)) recruited outside health care services in three of Spain's principal cities.

STUDY DESIGN

Cross-sectional cohort study. All participants (981) were street-recruited by chain referral procedures between April 2001 and December 2003. Face-to-face interviews were conducted using a structured questionnaire and dried blood spot samples were collected for serological testing.

RESULTS

No sample was positive for HTLV-1 and 27 samples were positive for HTLV-2; all of these were found only in Spanish IDUs in the cities of Madrid (17, 6.2%) and Barcelona (10, 3.5%). The only two factors significantly associated with HTLV infection in the logistic regression analysis were HIV infection (OR 5.7; 95% CI 2.2-14.8) and having injected in the last 30 days (OR 6.5; 95% CI 1.4-29.8). Having been in prison (OR 2.4; 95% CI 0.9-6.4) and HCV infection (OR 3.8; 95% CI 0.5-30.7), which were strongly and significantly associated in the bivariate analysis, were no longer significant in the logistic analysis. Almost the same variables were selected in the tree analysis, in which subjects could be classified into three groups: high prevalence (28.5%, HIV+ and HBV+ who had injected in the last 30 days), medium prevalence (17.8%) and low (<3%) or zero prevalence (HIV-, HCV- and HBV-).

CONCLUSIONS

HTLV-1 was not detected among young Spanish heroin users. HTLV-2 was not found in NIDUs (perhaps due to the low rate of sexual transmission); it was found only in IDUs from Madrid and Barcelona, but not in those from Seville. Its prevalence is very low and the main correlates of infection were HIV infection and injection as the usual route of heroin administration.

Human T Lymphotropic Virus Types I and II Western Blot Seroindeterminate Status and Its Association with Exposure to Prototype HTLV‐I

Human T lymphotropic virus types I and II (HTLV-I/II) Western blot (WB) seroindeterminate status, which is defined as an incomplete banding pattern of HTLV protein Gag (p19 or p24) or Env (GD21 or rgp46), is commonly observed. To investigate the significance of this finding, we examined HTLV-I/II serostatus and HTLV-I proviral load in 2 groups of individuals with WB seroindeterminate status. Low proviral loads were detected in 42% of patients with neurologic symptoms and 44% of voluntary blood donors. These data suggest that a subset of WB seroindeterminate individuals may be infected with prototype HTLV-I. To confirm this hypothesis, we evaluated HTLV-I/II serostatus and proviral load in prospectively collected specimens from 66 WB seronegative patients who had received HTLV-I-infected blood products by transfusion. Eight individuals developed WB seroindeterminate profiles after the transfusion. In addition, using a human leukocyte antigen type A*201-restricted HTLV-I Tax11-19 tetramer, we detected virus-specific CD8(+) T cells in peripheral blood mononuclear cells from WB seroindeterminate patients. These CD8(+) T cells were effective at targeting HTLV-I-infected cells. Collectively, the results suggest that HTLV-I/II WB seroindeterminate status may reflect a history of HTLV-I exposure. Our findings warrant further investigation of the possible clinical outcomes associated with WB seroindeterminate status.

Human T-cell lymphotropic virus type II in Guaraní Indians, Southern Brazil

Human T-cell lymphotropic virus type II (HTLV-II) is found in many New World Indian groups on the American continent. In Brazil, HTLV-II has been found among urban residents and Indians in the Amazon region, in the North. Guaraní Indians in the South of Brazil were studied for HTLV-I/II infection. Among 52 individuals, three (5.76%) showed positive anti-HTLV-II antibodies (enzyme-linked immunosorbent assay and Western blot). This preliminary report is the first seroepidemiological study showing HTLV-II infection among Indians in the South of Brazil.

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.

Molecular characterization of human T-cell lymphotropic virus type 2 (HTLV-II) from people living in urban areas of Sao Paulo city: Evidence of multiple subtypes circulation

BACKGROUND

In Brazil, human T-cell lymphotropic virus type I and type II (HTLV-I and HTLV-II) are co-circulating and possess approximately 65% homology, which results in high cross-reactivity in serological tests. Based on the detection of EIA and Western blot (WB) tests, HTLV serodiagnosis yields indeterminate results in high-risk population, with the true determination of HTLV-II prevalence requiring a combined serological and molecular analysis. Molecular analysis of HTLV-II isolates has shown the existence of four distinct subtypes: IIa, IIb, IIc, and IId. The aim of this study was to evaluate the routine EIA and WB used in Sao Paulo city, as well as molecular methods for confirmation of infection and HTLV-II subtype distribution.

RESULTS

Two hundred ninety-three individuals, who were enrolled in the HTLV out-clinic in Sao Paulo city, Brazil, between July 1997 and May 2003, were tested by EIAs, and positive sera 232 (79%) reactive by one of the tests. When these sera were tested by WB revealed 134 were HTLV-I, 28 HTLV-II, 4 HTLV-I/II, and 48 were indeterminate. Polymerase chain reaction (PCR) on the indeterminate group showed that 20 (42%) were HTLV-II and 28 were negative. From a total of 48 HTLV-II subjects with DNA available, restriction fragment length polymorphism (RFLP) of the env region revealed 47 HTLV-IIa and 1 HTLV-IIb. The phylogenetic analysis was performed on 23 samples, which identified 19 as subtype a, Brazilian subcluster, and 4 as subtype b. This is the first time HTLV-II subtype b has been described in Brazil. However, further studies, such as a complete nucleotide DNA sequencing, need to be done to confirm these findings.

HTLV-2 horizontal and vertical transmission in a family from a Brazilian urban area: seroepidemiological, clinical and molecular study

Human T cell lymphotropic virus type 2 (HTLV-2) has been shown to be endemic in Brazilian Indians and among intravenous drug users in urban areas, but transmission of this infection seems to be infrequent in the general population living in urban areas in Brazil. Six persons in three generations of a Brazilian family were evaluated to assess HTLV-2 transmission and its molecular features in the positive cases. The index was detected during screening (HTLV EIA) of donated blood in Fundação Hemominas, Belo Horizonte, Brazil. Confirmatory serological test and viral typing were performed by Western blotting and polymerase chain reaction. The family consisted of husband, wife (index case), three daughters, and the mother of the index case. The husband and one daughter were found positive, thus pointing to horizontal and vertical transmission. The husband was a truck driver, who reported casual sex during frequent traveling. The positive daughter was breast-fed for 3 months, as opposed to the remaining two (seronegative), who breast-fed for 1 month. The index case's mother was negative. To identify HTLV-2 subtype(s), phylogenetic analysis of the noncoding long terminal repeat region and part of the env and tax coding regions was performed. These new isolates from Belo Horizonte are related to subtype IIa but present a molecular variant with extended tax, previously reported in subtype IIc. Analyzing both LTR and env regions, the family's sequences clustered with isolates of Brazilian intravenous drug users and transfusion transmitted virus.

Seroprevalence of Human T Cell Leukemia Virus in HIV Antibody-Negative Populations in Rural Cameroon

Seven hundred forty-seven serum samples collected from humans in 4 separate rural village areas in Cameroon were examined for antibody to human T cell leukemia viruses (HTLVs) by use of an enzyme immunoassay followed by a Western blot assay. Of the 88 serum samples that the enzyme immunoassay found to be repeatedly reactive, the HTLV status of 49 samples was confirmed by Western blot assay to be HTLV type I, and the status of 6 samples was confirmed to be HTLV type II.

Heterogeneous geographic distribution of human T-cell lymphotropic viruses I and II (HTLV-I/II): serological screening prevalence rates in blood donors from large urban areas in Brazil

Brazil may have the highest absolute number of HTLV-I/II seropositive individuals in the world. Screening potential blood donors for HTLV-I/II is mandatory in Brazil. The public blood center network accounts for about 80.0% of all blood collected. We conducted a cross-sectional study to assess the geographic distribution of HTLV-I/II serological screening prevalence rates in blood donors from 27 large urban areas in the various States of Brazil, from 1995 to 2000. Enzyme immunoassay (EIA) was used to test for HTLV-I/II. The mean prevalence rates ranged from 0.4/1,000 in Florianopolis, capital of Santa Catarina State, in the South, to 10.0/1,000 in São Luiz, Maranhão State, in the Northeast. EIA prevalence rates are lower in the South and higher in the North and Northeast. The reasons for such heterogeneity may be multiple and need further studies.

Prevalence and molecular characterization of human T cell leukemia virus type 2 in a group of intravenous drug users coinfected with HIV type 1 in Portugal

Human T cell lymphotropic virus type 2 infections can be found in the large urban areas of the United States and Europe, where Spain and Italy are the most affected countries. The population most affected by the epidemic is characterized by high-risk behavior groups, mainly the sharing of needles between intravenous drug users (IDUs) with contaminated cellular blood products. It is also described that HTLV-2 infection appears as a coinfection with HIV-1. We have selected samples corresponding to 583 IDUs infected with HIV and screened for the presence of HTLV-1/2 antibodies. We have performed the molecular characterization of HTLV-2 in three confirmed positive cases on the basis of the long terminal repeat region. We can observe the Portuguese sequences (PortHl, PortNn, and PortVs) in the HTLV-2b cluster, grouping with the Spanish sequences, showing close phylogenetic relatedness. We may assume that HTLV-2 infection was introduced in Portugal from Spain. These results update previous reports that mentioned Portugal as being free of HTLV- 2 infections, and allow the identification of the subtype that is present, giving a first-hand description of the prevalence of HTLV-2 infection in a particular high-risk behavior group and justifying the importance of epidemiological surveillance in order to prevent dissemination of the infection.

Low prevalence of antibodies to human T-lymphotropic virus-I/II among blood donors in eastern Saudi Arabia

The seroprevalence of human T-lymphotropic virus (HTLV)-I/II was assessed in 13,443 consecutive blood donors in eastern Saudi Arabia between 1998 and 2001. Screening by enzyme-linked immunosorbent assay (ELISA) and confirmation by Western blot resulted in 8 (0.060%) positive cases, of which 5 (0.056%) belonged to Saudi and 3 (0.113%) to non-Saudi donors. The majority of the HTLV-positive donations (6/8) were for patients, and none had a history of known risk factor for HTLV-I/II transmission. Although the very low prevalence of HTLV-I/II among Saudi donors does not support routine screening, screening of donors from other nationalities may be initiated, especially those from HTLV-I/II endemic areas.

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.

Serologial screening of human T cell lymphotropic virus I and II (HTLV I/II) in blood banks by immunoblotting and enzyme-immuno assays: to demand or to defeat?

Human T cell lymphotropic virus I and II (HTLV I/II) has been recommended to be screened for blood donors since 1988, and it become a mandatory test to get college of american Pathologists (CAP) accreditation. The present study aimed at investigating the prevalence rate of HTLV I/II among Arab blood donors, to revise whether is its screening mandatory? Thirty-thousand (30,000) Arab donors along two years attending two central hospital blood banks in Jeddah. Antibodies to HTLV I/II have been screened using enzyme immunoassay (E.I.A) and immunoblotting assay (Western blot). Results revealed zero prevalence rate. Based upon this finding, no potential risk of HTLV I/II transmission among blood donors population exist. As screening for HTLV I/II is still mandatory, it could be done on pools of sera rather than on individual serum samples, after standardization of a pooling protocol, to fulfill coast-effectiveness and reduce the coasts by 90-95%.

High prevalence of HTLV-I and HTLV-II among blood donors in Argentina: a South American health concern

After an HTLV-I endemic area was discovered in Jujuy, a northwestern province in Argentina, to detect other possible foci of HTLV-I/II we started in 1997 a multicentric study to estimate the seroprevalence of HTLV-I/II including blood banks from different regions of the country. Out of 123,233 samples from nine different provinces, 68 proved seropositive with a final prevalence of 0.05% (95% CI = 0.0432-0.0704%). The seroprevalence ranged from 0.03 to 0.16% depending on the geographic location. An HTLV-I [odds ratio (OR) 12.7, 95% confidence interval (CI), 3.43-47.60] prevalence significantly greater was found in the northwest (Salta Province) and a nonsignificant but higher prevalence of HTLV-II in the North (Chaco). Two (0.001%) of the seropositive blood donors reported risk factors due to receiving transfusions and 19 (0.01%) were born in HTLV-I/II South American endemic areas. Although Argentina has been considered a nonendemic country for HTLV-I/II, the need for systematic screening for such infection became imperative based on the present study.

Antigenic mixture of synthetic peptides for the immunodiagnosis of HTLV I/II infection

Monomeric and chimeric synthetic peptides were used as coating antigens in four different mixtures in a solid phase immunoassay to select an optimal combination for the detection of antibodies to human T-cell lymphotropic virus (HTLV) in serum samples. The peptides, P-13 (gp21 I), Q5 (gp21 II)-GG-(gp46 II), and Q (gp46 I)-GG-(p19 I), represent immunodominant sequences from transmembrane protein (gp21), envelope protein (gp46), and core protein (p19) of HTLV I/II viruses; they were the most antigenic and specific peptides in previous studies. The sequences of the chimeric peptides were separated by two glycine residues. An indirect UltramicroEnzyme-linked immunosorbent assay (UMELISA) was used to evaluate the antigenicity of these peptide mixtures by using samples from anti-HTLV I/II PRP205(M), (n = 20), HTLV I-infected individuals from Cuba (n = 7), and HTLV I-positive sera from Colombia and Chile (n = 9). The specificity was evaluated with healthy blood donor sera (n = 300), anti-HIV 1-positive samples (n = 10), and other seropositive samples to different infectious agents. The highest sensitivity and specificity was obtained with mixture 1, which could be very useful in the immunodiagnostic of HTLV infection.

[Sero-epidemiological study on the human T-cell leukaemia virus type I/II infection in the east coastal areas of Fujian province]

OBJECTIVE

To study the seroprevalence of human T-cell leukaemia virus type I/II (HTLV-I/II) infection in adult population in the east coastal areas of Fujian and to explore the possible risk factors of HTLV-I/II.

METHODS

A total number of 3259 blood samples from drug users, sexually transmitted disease (STD) patients, prostitutes and blood donors for serologic assays during 1999 to 2002, were collected. All samples were screened for HTLV-I/II antibody, using enzyme linked immunosorbent assay (ELISA) kits. All of the positive samples were confirmed by western blot (WB) kits. Statistical analysis was done by Epi software, and chi(2) test by Fisher's exact test. P value < 0.05 was considered statistically significant.

RESULTS

The overall seroprevalence rate of HTLV-I/II in healthy populations was 0.06% including, 0.32% in drug users, 0.58% in STD patients and prostitutes respectively. HTLV-II had not been found. The seropositive rates for HTLV-I in STD patients and prostitutes were significantly higher than the findings among healthy populations (P < 0.05). There were no different seroprevalence rates between drug users and healthy populations (P > 0.05). No significant changes in HTLV-I prevalence rates were found in the different age groups as well as in Fuzhou and Linde cities (P > 0.05).

CONCLUSION

The result suggested that in the east coastal areas of Fujian province, HTLV-I was the main prevalent virus. The seroprevalence of HTLV-I was very low, with no HTLV-II. Neither age nor gender seemed to be HTLV-I risk factor in the east coastal areas of Fujian province, but the increase of exposure to sex might be one.

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.