Accuracy of supplementary serologic testing for human T-lymphotropic virus types I and II in US blood donors. Retrovirus Epidemiology Donor Study

Blood donations in the United States have been screened for antibody to human T-lymphotropic virus type I (HTLV-I) by HTLV-I enzyme immunoassay (EIA) since November 1988. Specimens repeatedly found to be reactive by EIA undergo confirmation by supplementary serologic tests. We assessed the accuracy of blood center testing of 994 HTLV-I EIA repeat-reactive specimens in five US blood centers between November 1988 and December 1991. Of 410 confirmed HTLV-I/II donations, 407 (99.3%) were infected with HTLV-I/II, as determined by polymerase chain reaction (PCR) (403 cases) and by repeat serologic testing (4 cases). The three false- positive results occurred in the first year of testing. Of 425 HTLV- indeterminate specimens, 6 (1.4%) were found to be infected by PCR (5 with HTLV-II and 1 with HTLV-I). None of 159 confirmatory test-negative donations was PCR positive. Of HTLV-I/II-seropositive specimens, 80.2% to 95.4% could be typed as HTLV-I or HTLV-II by type-specific serologic assays. These results support recommendations that HTLV-I/II- seropositive donors should be advised that they are infected with HTLV- I, HTLV-II, or HTLV-I/II (depending on results of type-specific assays). HTLV-indeterminate donors should be advised that their results only rarely indicate HTLV infection. HTLV confirmatory test-negative donors should be reassured that they are not infected with HTLV-I or HTLV-II.     

HTLV-1/2 Infection in Blood Donors from a Non-Endemic Area (Catalonia,Spain) between 2008 and 2017: A 10-Year Experience

Human T-cell lymphotropic virus type 1 and 2 (HTLV-1/2) screening is not mandatory in Spanish blood banks. In Catalonia, selective screening was introduced in 2008, followed by universal screening in 2011. We present herein a 10-year experience of HTLV testing in blood donors. HTLV-1/2 selective screening was performed using Ortho-Clinical Diagnostics HTLV-I/HTLV-II Ab-Capture ELISA between February 2008 and May 2009, then Abbott Prism HTLV-I/ HTLV-II assay until December 2010. Abbott Architect rHTLV-I/II assay was then used for HTLV-1/2 universal screening in pooled samples. INNO-LIA HTLV I/II Score (Fujirebio) and in-house HTLV-1/2 proviral DNA real-time PCR were used in reactive samples. Follow-up was offered to confirm HTLV-1/2 donors in Vall d’Hebron Hospital. Between 2008 and 2017, 51 blood donors were confirmed HTLV positive (46 HTLV-1, 4 HTLV-2 and 1 HTLV) out of 2,114,891 blood donations (1 in 41,468). Sixty-nine percent were female, median age was 40 years and most were born in Latin America (69%), followed by Europe (25%), Africa (4%) and Asia (2%). Screening of relatives and partners identified 12 additional HTLV-1 cases. Lookback studies did not show any HTLV-1/2 transmission. HTLV infections found in blood donors mirror epidemiological changes in the population of Spain. Consequently, HTLV should be considered a potential risk for recipients and calls for the design of optimal strategies to ensure transfusion safety.     

Coexistence of human T-lymphotropic virus types I and II among the Wayuu Indians from the Guajira Region of Colombia.

High prevalences of human T-lymphotropic virus type II (HTLV-II) infection have been found recently among certain Amerindian groups in North, Central, and South America. To determine if the Amerindians of Colombia are similarly affected, 523 sera, collected between 1987 and 1990 from nine culturally distinct Indian groups from widely separated regions, were tested for IgG antibodies against HTLV-I/II using enzyme-linked immunosorbent assay (ELISA) and Western blot. In addition, 243 sera from five non-Indian (black) and mixed-Indian (mestizo) populations were studied. Of the 766 individuals tested, 44 were ELISA positive, but of these, only four were Western blot positive. Three of the individuals confirmed positive by Western blot were infected with HTLV-II and one was infected with HTLV-I, as determined by differential ELISA. All four seropositive individuals belonged to a group of 62 Wayuu Indians, giving overall HTLV-I and HTLV-II seroprevalences of 1.6% and 4.8%, respectively. The coexistence of HTLV-I and HTLV-II in this Amerindian group provides an opportunity to study the factors governing transmission of these retroviruses.     

High prevalence of HTLV-II among intravenous drug abusers: PCR confirmation and typing

The polymerase chain reaction (PCR) was used to confirm the presence of human T-cell lymphotropic viruses (HTLV) in intravenous drug users (IVDU) whose sera were reactive by immunofluorescence assay (IFA) for HTLV-1/-II antibody. Peripheral blood mononuclear cells from 41 IFA-positive and 19 IFA-negative individuals were analyzed. HTLV sequences were detected in 39/41 IFA-positive samples; 36 were HTLV-II positive and 3 were HTLV-I positive. Two IFA antibody-positives were negative by both PCR and by enzyme immunoassay (EIA). One IFA and EIA antibody-negative sample was positive for HTLV-II by PCR. This study indicates a high prevalence of HTLV-II among IVDUs and further demonstrates the feasibility of using PCR to differentiate between HTLV-I and -II.     

Human T-cell leukemia virus type II infection frequently goes undetected in contemporary US blood donors

Serologic screening for human T-cell leukemia virus type I (HTLV-I) infection was begun in US blood banks with the licensure of enzyme- linked immunosorbent assays (ELISA) in December 1988. We examined the donation histories of the first 60 Western blot (WB)-confirmed HTLV- I/II positive donors to one blood center and found 8 had made 16 previous donations that scored negative on the screening ELISA. All 16 donations had ELISA absorbance below the cutoff for a positive assay, but still well above that of the average donation (17.6% +/- 5.7% of the cutoff). In a more extensive study, 17 donations from a total of 61,752 at six blood centers were both ELISA-positive and WB-positive for HTLV-I (4) or HTLV-II (13), and 218 samples had ELISA absorbance greater than 50% of the ELISA cutoff. One hundred seventy-eight of the 218 were tested further by WB and 11 were found positive. All 11 positives were confirmed by polymerase chain reaction; 10 had HTLV-II and 1 had HTLV-I. Thus, the HTLV-I-based screening ELISA missed at least 10 of 23, or 43% (95% confidence interval, 23% to 66%), of HTLV- II infections, compared with 1 of 5, or 20%, of HTLV-I infections.     

HTLV-I的分离研究

目的建立从HTLV-I感染者中分离HTLV-I的方法。方法采集HTLV-I感染者的肝素抗凝血,分离外周血单核细胞(PBMCs),与健康供者PBMCs或BJAB细胞共培养进行HTLV-I的分离,用P19抗原ELISA试剂盒检测共培养上清,提取培养细胞的基因组DNA,用HTLV-I的Gag、Tax两引物进行PCR扩增,对扩增产物进行琼脂糖凝胶电泳,并进行测序确定病原分离结果。结果从5例经WB确认的HTLV-I感染者中分离到4株HTLV-I毒株,P19抗原显示阳性结果,PCR法也扩增出HTLV-I前病毒DNA,对扩增产物的Gag区进行测序,亦证实该片段为HTLV-I Gag区序列。结论HTLV-I已首次在国内成功分离。     

Failure to detect evidence of human T-lymphotropic virus (HTLV) type I and type II in blood donors with isolated gag antibodies to HTLV-I/II.

Of the 267,650 blood donations from members of the US armed forces, 72 (0.027%) were serologically confirmed to be positive for human T-lymphotropic virus type I/II (HTLVpos) and 379 (0.14%) were Western blot (WB)-indeterminate with banding pattern restricted to the proteins encoded by the gag gene only (HTLVind). To determine whether these apparently healthy HTLVind blood donors are infected with HTLV-I or HTLV-II, coded specimens from randomly selected military blood donors (n = 73) were tested for antibodies to HTLV by WB and radioimmunoprecipitation assay (RIPA) using HTLV-I (MT-2) antigens, by enzyme immunoassay using synthetic peptides representing the immunodominant epitopes of HTLV, and for sequences of proviral HTLV DNA by the polymerase chain reaction (PCR). Of the 73 HTLVind donors, none showed presence of env reactivity by HTLV WB and RIPA. Minimal reactivity was observed with synthetic immunodominant motifs derived from the env protein of HTLV-I (Env-1(191-214) and Env-5(242-257)) or HTLV-II (Env-2(187-209) and Env-20(85-102)) and gag protein (Gag-1a(102-117) and Gag-10(364-385)). A peptide corresponding to the endogenous retroviral sequence with structural homologies to the gag protein of HTLVs (RTVLgag) reacted with antibodies not only in HTLVpos (88%) and HTLVind (42% to 66%) specimens, but also reacted with normal control subjects (60%). Furthermore, none of the 73 HTLVind specimens demonstrated presence of the HTLV genome when amplified with primers for the pol and tax/rex region. Six to 23 months from the initial test, 27 subjects still gave indeterminate WB patterns, and 13 of these repeat specimens were still negative for the presence of HTLV genome. We conclude that individuals at low risk for HTLV infection who have HTLVind WB reactivity are rarely, if ever, infected with HTLV-I or HTLV-II.     

Detection of human T-cell leukemia/lymphoma virus, type II, in a patient with large granular lymphocyte leukemia.

We studied a patient with large granular lymphocyte (LGL) leukemia for evidence of human T-cell leukemia/lymphoma virus (HTLV) infection. Serum from this patient was positive for HTLV-I/II antibodies by enzyme-linked immunosorbent assay (ELISA) and was confirmed positive in Western blot and radioimmunoprecipitation assays. Results of a synthetic peptide-based ELISA showed that the seropositivity was caused by HTLV-II and not HTLV-I infection. Analyses of enzymatic amplification of DNA from bone marrow sections using the polymerase chain reaction (PCR) were positive for HTLV-II specific gag, pol, env, and pX gene sequences. Cloning and sequencing of amplified products showed that the HTLV-II pol and pX sequences in patient DNA differed from the sequences of 17 other HTLV-II isolates examined in our laboratory. HTLV infection may have a role in some patients in the pathogenesis of LGL leukemia.     

Transmission of retroviruses from seronegative donors by transfusion during cardiac surgery. A multicenter study of HIV-1 and HTLV-I/II infections.

OBJECTIVE: To evaluate the effectiveness of serologic testing of blood donors for human immunodeficiency virus type 1 (HIV-1) and human T-cell lymphotropic virus types I and II (HTLV-I/II) infections and to estimate the risk for transmission of HIV-1 and HTLV-I/II by transfusion of seronegative blood from screened donors. DESIGN: A prospective multicenter cohort study of cardiac surgery patients who received multiple transfusions between 1985 and 1991. SETTING: Cardiac surgery services of three large tertiary care hospitals. PATIENTS: The study included 11,532 patients in three hospitals who had cardiovascular surgery. MEASUREMENTS: Incident HIV-1 and HTLV-I or HTLV-II infection. RESULTS: We detected two new HIV-1 infections among patients transfused with 120,312 units of blood components from seronegative donors. In each case a donor was detected on follow-up who had seroconverted since the donation. The HIV-1 infection rate was 0.0017% with an upper limit of the 95% CI of 0.0053%. Before donor screening for HTLV-I, transfusion of 51,026 units resulted in two HTLV-I infections (0.0039%) and four HTLV-II infections (0.0078%). After HTLV-I screening was instituted, one recipient was infected with HTLV-II among participants exposed to 69,272 units, a rate of 0.0014%. A corresponding HTLV-I/II-infected donor was found for this patient. CONCLUSION: Serologic screening of donors for antibodies to HIV-1 and HTLV-I coupled with exclusion of donors from groups having a relatively high risk for infection has led to a low incidence of transfusion-transmitted HIV-1 and HTLV-I/II infection in the United States. A small risk remains, however, despite these measures. We estimate the residual risk for HIV-1 and HTLV-II infection from transfusion of screened blood during the time of this study to be about 1 in 60,000 units.     

Progressive spastic myelopathy in a patient co-infected with HIV-1 and HTLV-II: autoantibodies to the human homologue of rig in blood and cerebrospinal fluid.

OBJECTIVE: Human T-cell leukemia virus types I (HTLV-I) and II (HTLV-II) are closely related human retroviruses. HTLV-I has been implicated in a chronic progressive myelopathy, known as tropical spastic paraparesis (TSP) or HTLV-I-associated myelopathy (HAM). We sought to determine whether autoantibodies to brain antigens were present in the cerebrospinal fluid (CSF) of a patient with chronic progressive spastic myelopathy with evidence of both HIV-1 infection and HTLV-I/II seropositivity. DESIGN: A 54-year-old bisexual man with clinical features of HAM/TSP of over 20 years' duration was followed. METHODS: We applied discriminatory DNA amplification (polymerase chain reaction) to distinguish HTLV-I from HTLV-II and to verify co-infection with HIV-1. The patient's CSF was used to screen a human brain cDNA expression library to identify antibodies directed against brain antigens. Autoreactive bacteriophage clones were isolated and sequenced. RESULTS: The patient was found to be co-infected with both HIV-1 and HTLV-II, but not with HTLV-I. HTLV-II proviral levels in the peripheral blood remained relatively constant, despite therapy with zidovudine. Prominent oligoclonal banding of immunoglobulins was present in the patient's CSF. A single repeatedly reactive cDNA clone was identified, by screening with CSF antibody, sequenced, and found to be the human homologue of the rat insulinoma gene, rig. CONCLUSIONS: HTLV-II infection may predispose to development of a HAM/TSP-like illness. Autoimmune mechanisms, such as autoantibody formation, may play a role in pathogenesis.     

A prospective study of sexual transmission of human T lymphotropic virus (HTLV)-I and HTLV-II

BACKGROUND: Cross-sectional studies support sexual transmission of human T lymphotropic virus (HTLV)-I/II; however, prospective incidence data, particularly for HTLV-II, are limited. METHODS: A cohort of 85 HTLV-positive (30 with HTLV-I and 55 with HTLV-II) blood donors and their stable (>or=6 months) heterosexual sex partners were followed biannually over the course of a 10-year period. RESULTS: Four of 85 initially seronegative sex partners of HTLV-I and -II carriers seroconverted, for an incidence rate (IR) of 0.6 transmissions/100 person-years (py) (95% confidence interval [CI], 0.2-1.6). This includes 2 HTLV-I transmissions/219 py (IR, 0.9 transmissions/100 py [95% CI, 0.1-3.3]) and 2 HTLV-II transmissions/411 py (IR, 0.5 transmissions/100 py [95% CI, 0.06-1.8]), with no significant difference by HTLV type. There were 2 male-to-female (IR, 1.2 transmissions/100 py [95% CI, 0.1-4.3]) and 2 female-to-male (IR, 0.4 transmissions/100 py [95% CI, 0.05-1.6) transmissions. HTLV-I or -II proviral load was 2 log10 lower in newly infected partners than in index positive partners who transmitted HTLV (P=.007). CONCLUSIONS: The incidence of sexual transmission of HTLV-II may be similar to that of HTLV-I, and female-to-male transmission may play a more important role than previously thought. HTLV-I and -II proviral load may be lower in sexually acquired infection, because of a small infectious dose.     

Low risk of mother-to-child transmission of human T lymphotropic virus type II in non-breast-fed infants. The NYC Perinatal HIV Transmission Collaborative Study.

The transmissibility of human T lymphotropic virus (HTLV) type II from mother to child was investigated. Of 236 women enrolled during pregnancy in a study of mother-to-child transmission of human immunodeficiency virus in 1986-1988, 21 (8.9%) were seropositive for HTLV-I/II. All 21 mothers were infected with HTLV-II by synthetic peptide testing and polymerase chain reaction (PCR). HTLV-II-infected women were older (median age, 34 vs. 28 years), more likely to be black (70% vs. 38%), and more likely to report past or current intravenous drug use (85% vs. 56%) than HTLV-II-uninfected women. Of 20 non-breast-fed infants born to 19 of these HTLV-II-infected women, none had detectable HTLV-II by PCR done on peripheral blood mononuclear cells obtained at birth to 36 months of age. Serologic testing of these infants revealed gradual disappearance of HTLV-I/II antibody. While this study does not rule out the possibility of perinatal HTLV-II transmission, the data suggest that it occurs rarely in the absence of breast-feeding.     

Prevalence of HTLV-I-associated T-cell lymphoma.

In order to assess the prevalence rate of HTLV-1-associated T-cell lymphomas and human retrovirus infection in general, approximately 21,000 individuals representing various patient populations, retroviral risk groups, and blood donors were examined for HTLV-I, HTLV-II, HIV-1, or HIV-2 infection using serologic and PCR assays. The prevalence rates among volunteer blood donors were 0.02% and 0% for HTLV and HIV, respectively. Significantly increased HTLV prevalence rates were observed among paid blood donors, African American health care clinic patients, Amerindians, recipients of HTLV-positive cellular blood products, intravenous drug users, sexual contacts and family members of HTLV-positive people, and patients with primary thrombocytosis and other-than-low-grade non-Hodgkin's lymphoma (NHL). Among some of these groups there were significant differences in the prevalence of HTLV-I versus HTLV-II. The eight HTLV-positive NHL patients all had mature, high-grade, CD4+ T-cell lymphomas with clonally integrated HTLV-I, for a prevalence of 4% among other-than-low-grade NHL patients. Seven of the eight died from their disease within 2 years despite treatment. Interestingly, two groups at risk for HTLV infection, namely needle stick victims and recipients of HTLV-infected and/or pooled plasma products, showed no evidence for infection. Significantly increased HIV-1 prevalence was observed among paid blood donors, African Americans, homosexuals, female prostitutes, hemophiliacs, and other-than-low-grade NHL patients. Only one patient was infected with HIV-2. Of the nine HIV-positive, other-than-low-grade NHL patients, seven HIV-1 positives had B-cell lymphomas, one HIV-1 positive had an HTLV-I-positive CD4+ T-cell lymphoma, and one infected with HIV-2 had a CD4+ T-cell lymphoma that was HTLV negative. The data indicate that HTLV-I lymphoma, while uncommon, is not necessarily rare among other-than-low-grade NHL cases in the United States and, given its poor prognosis, should probably be studied separately in clinical trials.     

Molecular analysis of human T cell lymphotropic virus type 1 and 2 (HTLV-1/2) seroindeterminate blood donors from Northeast Iran: evidence of proviral tax, env, and gag sequences

Human T cell lymphotropic virus type 1 and 2 (HTLV-1/2) Western blot indeterminate results are a problem for blood banks in endemic areas. To determine the prevalence of HTLV-1/2 infection among indeterminate donors, we analyzed 130 cases from Mashhad, an HTLV-1/2 endemic area in Northeast Iran. The most frequent Western blot bands were GD21 alone (37.2%) followed by rgp46-2 alone (32.1%). We further tested 40 available DNA samples of these cases by PCR for viral sequences, tax, gag, and pol, and found five cases (12.5%) to be positive for two or three HTLV-1 genes. There were no significant age, sex, and blood group differences between PCR-positive and PCR-negative cases. Among PCR-positive individuals, the most prevalent Western blot bands were variable combinations of rgp46-1, GD21, and gp21. The mean of the optical density (OD) of the enzyme-linked immunosorbent assay (ELISA) test was significantly higher in PCR-positive individuals. The frequency of the rgp46-1 band was also significantly higher in PCR-positive cases compared to PCR-negative ones. In conclusion, the majority of HTLV-indeterminate donors lack the HTLV provirus and therefore are not considered infected. However, in some cases with higher ODs in the ELISA test and seroreactivity to env proteins, rgp46-1 and GD21 in particular may be indicative of infection and need further evaluation by molecular methods.     

Clinical and epidemiological aspects of HTLV-II infection in São Paulo, Brazil: presence of tropical spastic paraparesis/HTLV-associated myelopathy (TSP/HAM) simile diagnosis in HIV-1-co-infected subjects

In this study, the epidemiological and clinical features observed in solely HTLV-II-infected individuals were compared to those in patients co-infected with HIV-1. A total of 380 subjects attended at the HTLV Out-Patient Clinic in the Institute of Infectious Diseases "Emilio Ribas" (IIER), S?o Paulo, Brazil, were evaluated every 3-6 months for the last seven years by infectious disease specialists and neurologists. Using a testing algorithm that employs the enzyme immuno assay, Western Blot and polymerase chain reaction, it was found that 201 (53%) were HTLV-I positive and 50 (13%) were infected with HTLV-II. Thirty-seven (74%) of the HTLV-II reactors were co-infected with HIV-1. Of the 13 (26%) solely HTLV-II-infected subjects, urinary tract infection was diagnosed in three (23%), one case of skin vasculitis (8%) and two cases of lumbar pain and erectile dysfunction (15%), but none myelopathy case was observed. Among 37 co-infected with HIV-1, four cases (10%) presented with tropical spastic paraparesis/HTLV-associated myelopathy (TSP/HAM) simile. Two patients showed paraparesis as the initial symptom, two cases first presented with vesical and erectile disturbances, peripheral neuropathies were observed in other five patients (13%), and seven (19%) patients showed some neurological signal or symptoms, most of them with lumbar pain (five cases). The results obtained suggest that neurological manifestations may be more frequent in HTLV-II/HIV-1-infected subjects than those infected with HTLV-II only.     

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.     

HTLV-II down-regulates HIV-1 replication in IL-2-stimulated primary PBMC of coinfected individuals through expression of MIP-1alpha

The influence of human T-cell leukemia/lymphoma virus type II (HTLV-II) in individuals also infected with HIV-1 is poorly understood. To evaluate the reciprocal influence of HTLV-II and HIV-1 infection, primary peripheral blood mononuclear cell (PBMC) cultures from coinfected individuals were established in the presence of interleukin 2 (IL-2). In these cultures, the kinetics of HTLV-II replication always preceded those of HIV-1. Noteworthy, the kinetics of HIV-1 production were inversely correlated to the HTLV-II proviral load in vivo and its replication ex vivo. These observations suggested a potential interaction between the 2 retroviruses. In this regard, the levels of IL-2, IL-6, and tumor necrosis factor-alpha (TNF-alpha) were measured in the same coinfected PBMC cultures. Endogenous IL-2 was not produced, whereas IL-6 and TNF-alpha were secreted at levels compatible with their known ability to up-regulate HIV-1 expression. The HIV-suppressive CC-chemokines RANTES, macrophage inflammatory protein-1alpha (MIP-1alpha), and MIP-1beta were also determined in IL-2-stimulated PBMC cultures. Of interest, their kinetics and concentrations were inversely related to those of HIV-1 replication. Experiments were performed in which CD8(+) T cells or PBMCs from HTLV-II monoinfected individuals were cocultivated with CD4(+) T cells from HIV-1 monoinfected individuals separated by a semipermeable membrane in the presence or absence of antichemokine neutralizing antibodies. The results indicate that HTLV-II can interfere with the replicative potential of HIV-1 by up-regulating viral suppressive CC-chemokines and, in particular, MIP-1alpha. This study is the first report indicating that HTLV-II can influence HIV replication, at least in vitro, via up-regulation of HIV-suppressive chemokines. (Blood. 2000;95:2760-2769)     

Human T lymphotropic virus type II (HTLV-II) infection in a cohort of New York intravenous drug users: an old infection?

To identify risk factors for human T lymphotropic virus type II (HTLV-II) infection in intravenous drug users (IVDUs), participants in a longitudinal study of human immunodeficiency virus (HIV) infection in a New York methadone maintenance program were studied. Of 270 participants tested for HTLV-I/II, 21 (8%) were seropositive. Of those, 15 (71%) had HTLV-II-specific sequences by polymerase chain reaction (PCR) and 1 (5%) had both HTLV-I- and -II-specific sequences; 3 persons with indeterminate serologic results were also PCR-positive for HTLV-II. HTLV-II infection was significantly associated with older age but was not predicted by sex, race, socioeconomic status, transfusion history, or HIV infection status. Behavioral factors since 1978, such as duration and frequency of intravenous drug use, needle sharing, visits to shooting galleries, or number of sex partners, were also not associated with HTLV-II infection. These findings are in contrast with the association of these risk factors with HIV in this group and suggest that, among IVDUs, HTLV-II is an older endemic infection that is less efficiently transmitted than HIV.     

HIV-2 and HTLV-I/II infections in Spain

Up to December 2002, a total of 56, 566 and 109 cases of human T-lymphotropic virus type 1 (HTLV-I), HTLV-II and human immunodeficiency virus type 2 (HIV-2) infection, respectively, were identified in Spain. Most HTLV-I- and HIV-2-infected subjects were immigrants from endemic areas or Spaniards who had traveled to, or had sexual contacts with natives from, these areas. In contrast, HTLV-II infection was mainly limited to Spanish intravenous drug users (IDU) who were frequently coinfected with HIV-1. Among HTLV-I-infected patients, 12 developed subacute myelopathy and 4 adult T-cell leukemia. As for the HIV-2-positive subjects, only 20 (18.3%) developed AIDS. There was no evidence of an increase in the incidence of HIV-2 and HTLV-I infections over time. In contrast, HTLV-II infection has spread in recent years among the HIV-1-positive IDU population in prisons, with a rate of 18% in some regions of Spain. Nevertheless, the prevalence of HTLV-II infection in HIV-1-positive IDU outpatients is still low (4.7%).