Human T-cell lymphotropic virus type I infection in Barbados: results of a 20-year follow-up study

Forty-one human T-cell lymphotropic virus type I (HTLV-1)-seropositive individuals were identified among 1,012 subjects with stored serum samples from a health and seroepidemiological survey conducted in Barbados in 1972. These 41 subjects plus 79 HTLV-1 seronegative household members were targeted in a follow-up study 20 years later. Sixteen seropositive subjects and 22 seronegative subjects were interviewed, examined, and phlebotomized. There were no changes in HTLV-1 serostatus between the 1972 and follow-up serum samples. Three (19%) of the seropositive subjects had HTLV-1-associated disorders: two with dermatitis and one with "smoldering" adult T-cell leukemia. Neurologic and immunologic function was similar in HTLV-1-seropositive and HTLV-1-seronegative subjects. HTLV-1 antibodies persist over many years, and the risk for seroconversion of household contacts is low.

Prevalence of HTLV type I infection in Iran: a serological and genetic study

Several publications describe the presence of the human T cell lymphotropic virus type I (HTLV-I) in Jewish individuals born in Mash-had, Iran. We report here the results of HTLV-I serological and genetic studies in the non-Jewish population of Mash-had as well as a neighboring area: Gonbad-Kavous. Seven hundred and seven serum samples from Mash-had (694 healthy individuals and 13 patients with lymphoma) and 90 from Gonbad-Kavous were tested for HTLV antibodies by gelatin particle agglutination assay (PA) and confirmatory Western blots (WBs). Seropositive rates of 3.0% (21 of 694) in Mash-had, 0% (0 of 90) in Gonbad-Kavous, and 100% (13 of 13) in lymphoma cases were observed. HTLV-I DNA sequence were amplified by polymerase chain reaction directly from the fresh PBMCs of seropositive individuals. Phylogenetic analysis of the viral DNA sequence indicated that the HTLV-I present in Mash-had belong to the HTLV-I cosmopolitan clade. Altogether, these data indicate that Mash-had, located in northeastern Iran, is a newly recognized endemic center for HTLV-I.

Prevalence of HIV-1, HIV-2 and HTLV antibody, in Fortaleza, Ceara, Brazil, 1993-1994

To evaluate the respective part of HIV-1, HIV-2, and human T lymphotropic virus (HTLV) infection in Fortaleza, the principal city of the Ceara state (Northeast of Brazil), a cross-sectional seroepidemiological survey was conducted from July 1993 to February 1994 in 6 selected groups: pregnant women, tuberculosis (Tb) patients, sexually transmitted disease (STD) patients, female and male commercial sex workers (CSWs) and prisoners. Sera were screened by Mixt HIV-1/HIV-2 commercial enzyme immunoassay and ELISA HTLV I/II. Each serum found positive by ELISA was confirmed by Western blot. A total of 2917 persons were interviewed, of whom 2754 (94.4%) agreed to participate and gave a blood sample. Twenty-eight were found to be HIV-1 antibody positive. The prevalence ranged from 0.25% in pregnant women to 2.9% in male CSWs. The prevalence was 1% in STD patients and 0.44% in Tb patients. None of the sera was found positive for HIV-2. The prevalence of antibodies to HTLV-1 varied from 0.12% in pregnant women to 1.21% in female CSWs. Five sera were positive for HTLV-II. These results confirm the hypothesis that the HIV epidemic in Northeastern Brazil is still limited to high risk groups. Repeated cross-sectional surveys of this type should be performed as a surveillance tool to study the dynamics of this epidemic in low prevalence areas. Defining risk factors should allow targeting of intervention strategies.

[Serological and molecular-biological study of T-cell leukemia virus in Turkmenistan]

Seroepidemiological and molecular-biological screening of 1510 donor blood samples, collected from the residents of the town of Ashgabat (Turkmenistan), for lymphotropic virus of human T-cellular leukemia (HTLV) virus revealed one donor with a high level of immune response to a wide spectrum of viral proteins. Three donors were serologically assessed as dubious, for their sera contained antibodies to gag gene protein but no antibodies to env gene protein. Screening of family members of the donor infected with HTLV-1 revealed four more highly reactive carriers of HTLV-1 virus. The presence of proviral sequences of HTLV-1 in the lymphocyte DNA of infected donor and her relatives was confirmed by polymerase chain reaction and subsequent Southern-blot hybridization of specific amplification products. Proviral sequences of gag, pol, and LTR genes were detected in all the cases. Short-term culturing of peripheral blood lymphocytes of all seropositive subjects was associated with expression of HTLV-1 structural proteins. Analysis of the possible routes of transmission of HTLV-1 isolated in Turkmenistan permits us to hypothesize an Iranian origin of the isolated virus strain.

Mother-to-child transmission of human T-cell lymphotropic virus types I and II (HTLV-I/II) in Gabon: a prospective follow-up of 4 years

SUMMARY

For 4 years. we determined the mode and risk of mother-to-child transmission of HTLV-I in a prospective cohort of 34 children born to seropositive mothers in Franceville, Gabon. We also determined the prevalence of antibodies to HTLV-I/II in siblings born to seropositive mothers. Antibodies to HTLV-I/II were detected by Western blot, and the proviral DNA was detected by the polymerase chain reaction (PCR). The risk of seroconversion to anti-HTLV-I for the 4 years of follow-up was 17.5 percent. Anti-HTLV-I/II and proviral DNA were only detected after age 18 months. We observed a seroprevalence rate of 15 percent among the siblings born to HTLV-I/II seropositive mothers. Furthermore, we report a case of mother-to-child transmission of HTLV-II infection in a population of HTLV-II-infected pregnant women that is emerging in Gabon. The lack of detection of HTLV-I/II proviral DNA in cord blood and amniotic fluid and, furthermore, the late seroconversion observed in the children indirectly indicate that mother-to-child transmission occurred postnatally, probably through breast milk.

Human T-lymphotropic virus type II seroprevalence among emergency department and clinic patients

To determine the seroprevalence of human T-lymphotropic virus types I and II (HTLV-I and HTLV-II) among emergency department and clinic patients at a San Francisco, California, hospital, consecutive patients from 4 outpatient settings-emergency department, medical clinic, antenatal clinic, and neighborhood health centers-were tested for antibody to 1 of the viruses using an enzyme-linked immunosorbent assay and Western blot test. Of 4,019 patients, 169 (4.2%) had antibody to HTLV-I or -II; the seroprevalence of HTLV-II (3.5%) was greater than that of HTLV-I (0.7%). Seroprevalence for HTLV-II was highest in the emergency department (6.9%) and neighborhood clinics (3.9%) and in those aged 30 to 59 years (5.9%). Crude HTLV-II prevalence was higher in men (5.2%) than in women (2.2%), but sex was not an independent risk factor after age and location were controlled for. This study showed a higher seroprevalence of HTLV-I and HTLV-II among outpatients than did previous studies, probably because of a high proportion of injection-drug users. In view of the recent description of HTLV-II-associated myelopathy, studies of neurologic disease in this population may be warranted. HTLV-II should be included in the list of occupationally transmitted infections for hospitals with many injection-drug-using patients.

[Low incidence of non-Hodgkin lymphoma but high seroprevalence of HTLV-I in Curaçao]

OBJECTIVE

To determine whether the low incidence of non-Hodgkin's lymphoma (NHL) in Curaçao has changed in comparison with the increase in incidence in many western countries, and to investigate the role of the HTLV-I infection that is endemic in the Caribbean area.

DESIGN

Retrospective.

SETTING

Curaçao, Netherlands Antilles.

METHOD

Retrospective file analysis in the only hospital in Curaçao.

RESULTS

During the period 1987-1992, 31 patients had a histologically confirmed diagnosis of NHL resulting in an annual incidence rate of 4.9/100,000 adults. There was a strong age-related increase in NHL incidence rate (0.5 for patients < 30 years to 17.8 for patients > or = 70 years), with a male to female ratio of I. (In the western world the incidence is 12-14, in the seventies it was 4.5 in Curaçao.) Seven of 12 patients (58%) tested were seropositive for HTLV-I. Median survival was 6 months, despite conventional therapy.

CONCLUSION

While HTLV-I infection can often be demonstrated in NHL patients in Curaçao, NHL incidence has remained low over the past 25 years.

HTLV infection in ELISA-negative blood donors

Human T lymphotropic viruses (HTLVs) have a limited spread in the general populations of Western countries. Consequently, the transfusional risk for HTLV is consider to be low in Italy and the screening for anti-HTLV-I/II antibodies has not yet been introduced. In 1992, 1087 blood donors attending a transfusional center in northern Italy underwent anti-HTLV-I/II screening carried out by means of two different ELISA tests. Eleven individuals who were negative at the first test were borderline at the second, eight of them showing reactivity to Western blot (WB). Polymerase chain reaction (PCR) for the detection of HTLV DNA, subsequently performed on the peripheral blood mononuclear cells of these 11 subjects, was positive in the same 8 WB-reactive donors. Five of them were infected by HTLV-II, and three by HTLV-1. Our results confirm that the sensitivity of the ELISA tests actually used for the detection of HTLV-I/II antibodies is low, and that HTLV-infected blood donors may be frequently undetected. Moreover, in our study population, the prevalence of HTLV infection (0.73%) was greater than that which might be expected from the existing seroepidemiological data in Italy.

HIV and infections of similar transmission patterns in a drug injectors community of Santos, Brazil

To study the prevalence of HIV and infections with related transmission patterns, we interviewed and obtained blood samples from 220 injecting drug users (IDUs), sampled by snowballing, from the city of Santos in the state of São Paulo, Brazil, where the estimated number of IDUs (10,000) comprises approximately 2% of the entire population. Seroprevalence of HIV, hepatitis B and C, syphilis, and HTLV (1 and 2) was assessed and compared with that in 197 blood donors from the same city, matched for age and gender. Risk behavior related to HIV was assessed by a standard questionnaire applied to the IDU sample. Univariate and multivariate analyses of the risk factors were performed. Seroprevalences found were 62% for HIV, 75% for HCV, 75% for HBV, 34% for syphilis, and 25% for HTLV (1 and 2) among IDUs, which compare with 0.0%, 2%, 23%, 12%, and 1% for blood donors, respectively. The risk for parenterally transmitted infections in this IDU community was higher than that for sexually transmitted infections (odds ratio for syphilis, 3.57; hepatitis B, 10.0; and hepatitis C, 100). The results of the mutivariate risk analysis showed that daily rate of ID use >5 times/day (OR = 6.73), not changing behavior to avoid AIDS (OR= 3.28), ID use >15 days/month (OR = 2.72), and ID use in the last 2 months (OR = 2.23) were the risk behaviors significantly associated with HIV infection.

Seroepidemiological study of retroviruses (HTLV-I/II, HIV-1, HIV-2) in the Department of Atacora, northern Benin

A seroepidemiological survey to determine the prevalence of retrovirus infection (HTLV-I/II, HIV-1, HIV-2) by representative sampling of the general population in the Department of Atacora in north-western Benin is reported. The seroprevalence rate of HTLV-I in this sample was at 1.86% (95% CI 1.20-2.52%). This is in agreement with prevalence rates reported from neighbouring countries of the sub-region. No sera were found positive for HTLV-II. Seropositivity to HIV-1 was 0.3%; HIV-2 seropositivity was not encountered.

Expression of CD26/dipeptidyl peptidase IV in adult T cell leukemia/lymphoma (ATLL)

The association of CD26/dipeptidyl peptidase IV (DPPIV) and human T lymphotropic virus type I (HTLV-I) was studied by two approaches. First, we examined the expression of CD26 in peripheral blood mononuclear cells (PBMC) from the patients with adult T cell leukemia/lymphoma (ATLL), an HTLV-I-related malignancy. The expression of CD26 on the surface of PBMC was decreased in all 20 patients with ATLL compared with those from normal individuals (P < 0.01) and the expression of the CD26 gene transcript was not detectable in seven out of eight patients with ATLL. Then we compared the quantity of viral DNA in CD26-negative (CD26-) and CD26-positive (CD26+) cells obtained from 17 HTLV-I healthy carries by using a polymerase chain reaction method. The CD26-cells had a higher copy number of viral DNA than CD26+ cells. These findings indicate that HTLV-I has in vivo tropism to CD26- cells, suggesting that some phenotypes of ATLL cells reflect the in vivo cellular tropism of HTLV-I.

Epidemiology of HTLV-I infection in Spain. HTLV Spanish Study Group

BACKGROUND

The human T-lymphotropic virus type I (HTLV-I) has been implicated in the genesis of tropical spastic paraparesis (TSP), adult T-cell lymphoma (ATL), and some cases of uveitis, subacute arthropathies, chronic dermatitis and lymphocytic alveolitis. The virus is endemic in some areas of the Caribbean basin, Japan, subSaharan Africa, Central and South America, Middle East and Melanesia. Given that HTLV-I is transmitted through similar ways to HIV, screening in blood donors is recommended in some countries.

MATERIALS AND METHODS

The clinical, epidemiological and virological characteristics of 27 patients with HTLV-I infection were identified in Spain up to September 1995.

RESULTS

Eighteen cases were Spanish natives and 9 were immigrants from endemic areas. Fifteen were male and 12 were female. The majority (12/18; 66.7 percent) of subjects born in Spain had resided in endemic areas or had had sexual partners from these regions. Four patients had TSP, three had ATL and one developed lymphomatous granulomatosis and T-cell lymphoma. The remaining HTLV-I subjects were asymptomatic at the time of diagnosis. Four cases were identified from screening of blood donors.

CONCLUSION

HTLV-I is present in Spain, affecting natives and, less frequently, immigrants from endemic areas. Both neurological and lymphoproliferative diseases have been recognized in a quarter of patients.

HTLV-I and HTLV-II infections in subjects at risk for HIV-I infection from southeastern Italy (Apulia region)

To assess the prevalence of HTLV-I and HTLV-II infections in different groups at risk for HIV-I infection, a study on 867 subjects was carried out by means of serological and PCR analyses. Serum specimens were collected from 268 intravenous drug users (IVDU), 66 homosexual men, 248 subjects with sexually transmitted diseases (STD), 105 thalassemics and 180 hemophiliacs. Sera from 3 IVDU and a sample from an STD patient were confirmed as HTLV-II seropositive; a thalassemic patient was seropositive for HTLV-I; a homosexual man, though confirmed as HTLV-I/II-seroreactive, could not be typed by serological methods. No hemophiliac was found to be HTLV-I/II-reactive. All 3 HTLV-II-seroreactive IVDU and the HTLV-I-infected thalassemic were confirmed by PCR; an additional sample from an IVDU, indeterminate by Western blot, was confirmed to be positive for HTLV-II by PCR. Subtyping of HTLV-II samples indicated the presence of II/b subtype in all 4 cases. Up to now, the reservoir for HTLV-II infection in southeastern Italy is mainly represented by IVDU, while HTLV-I infection seems to be sporadic.

A population-based epidemiological study of human T-cell leukemia virus type I infection in Kin-Hu, Kinmen

Kinmen is a group of small islands located between Taiwan and Fu-Kien Province of mainland China. The general population in Kinmen are descendants of immigrants from mainland China who began arriving around 317 A.D. Since it has been reported that 0.48% of adults in Taiwan have HTLV-I infection, the decision was made to conduct a community-based epidemiological study in Kinmen to understand the origin and dissemination of HTLV-I in north-east Asia. Over 68% of residents of Kin-Hu township in Kinmen over 30 years of age participated in this study. Eight of 1,425 males and 14 of 1,595 females had HTLV-I infection. Antibody reactivities were further tested by Western blot assays with HTLV-I or HTLV-II type-specific recombinant envelope glycoproteins, and it was determined that all of those infected had HTLV-I and none had HTLV-II. Logistic regression was used for multivariate analysis. The final model indicated that the significant factors associated with HTLV-I infection in Kinmen were age and coastal residency. Age was positively correlated with HTLV-I infection. The eastern coastal area had a rate of HTLV-I infection 3.1 times higher than other areas in Kin-Hu. Further genetic analysis in Kinmen is needed to elucidate a relationship with other HTLV-I isolates in the world.

HTLV-I infection in the Free State region of South Africa: a sero-epidemiologic study

Human T-lymphotropic virus type I (HTLV-1) is associated with tropical spastic paraparesis (TSP) and adult T-cell leukemia/lymphoma. HTLV-I infection is endemic in certain parts of the Natal/KwaZulu region of South Africa. No studies on the seroprevalence of HTLV-I infection in the Free State (FS) have been published. This study was designed to determine the prevalence of HTLV-I antibodies among different patient groups in the FS. Sera from 863 patients were analyzed. There were: 178 asymptomatic rural Blacks, 200 asymptomatic urban Blacks, 50 asymptomatic Whites, 60 patients with spastic myelopathy, 70 patients with other neurologic disorders, 12 patients with T-cell haematologic malignancies and 293 human immunodeficiency virus (HIV) seropositive patients. Sera were tested for the presence of HTLV-I/II antibodies using an enzyme linked immunosorbent assay (ELISA). Positive results were confirmed using a modified Western blot assay. None of the asymptomatic Whites were HTLV-I antibody positive (95 pc confidence interval (CI): 0 to 7 pc), while 2 pc (95 CI: 0.5 to 5 pc) of asymptomatic urban Blacks and 1.1 pc (95 pc CI: 0.14 to 4 pc) of asymptomatic rural Blacks had HTLV-I antibodies. Of the group of patients with spastic myelopathy 33.3 pc (95 pc CI: 21.7 to 46.7 pc had HTLV-I antibodies, while none of the patients with T-cell haematologic malignancies (95 pc CI: 0 to 26.5 pc) or other neurologic disorders (95 pc CI: 0 to 5 pc) had HTLV-I antibodies. Of the HIV seropositive patients 6.1 (95 pc CI: 4 to 9.5) were co-infected with HTLV-I. HTLV-I infection is present in the Free State. It is strongly associated with spastic myelopathy in this region. HIV seropositive patients have a high rate of HTLV-I co-infection.

HTLV infection in a group of prostitutes and their male sexual clients in Brazil: seroprevalence and risk factors

Sera from 653 female prostitutes and 153 male sexual clients living in the city of Santos, São Paulo, Brazil, were tested for the presence of antibodies to human T cell lymphotropic virus types I and II. Seroprevalence for HTLV-I in the females was 2.8% and in the males 2.0%. Infection by HTLV-II could not be demonstrated. Seropositivity to HTLV-I was not associated with intravenous drug use, modality of sexual behaviour or a history of sexually transmitted disease. Among the prostitutes, the prevalence of anti-HTLV-I antibodies was 3 times higher in those with a history of blood transfusion (P = 0.01).

Performance of HTLV-1 screening assays in Brazil

In recent years a variety of studies have been carried out to compare the accuracy (generally expressed in terms of sensitivity and specificity) of commercially available anti-HTLV tests. None of these studies were performed in Brazil or in any other South American country. During the characterization of our Brazilian reference panel we evaluated the sensitivities and specificities of the Abbott HTLV EIA (100%; 89.7%) and the Biochrom HTLV-1/-2 ELISA (100%; 42.4%). Our conclusion was that both assays may be problematic in terms of correctly identifying HTLV-negative sera. We therefore adjusted the cut-off values using receiver operating characteristics (ROC). ROC analysis, which involves calculating sensitivity and specificity for several cut-off values, can be used to ascertain the co-variation in the specificity and sensitivity of any assay giving quantitative results. The optimum cut-off value for the assay in a given study population is the point that gives highest possible sensitivity in conjunction with a small false-positive fraction. Using the HTLV-1/-2 Western blot as the "gold standard", we were able to improve the specificity of the Biochrom HTLV-1/-2 assay to 95% without affecting its sensitivity of 100%. However, it seems that when using the Biochrom HTLV-1/-2 ELISA, there may be problems in separating positive and negative sera. In the case of the Abbott HTLV EIA, our ROC analysis revealed that the cut-off value suggested by the manufacturer was nearly identical to the optimum cut-off value. Adjustment will affect neither sensitivity nor specificity. However, a slight adjustment of the cut-off value result in a clearer separation of the positive and negative populations. Furthermore, we assume that this adjustment will help to avoid false-positive results when larger serum panels are investigated. Further investigations will show whether or not this problem is linked to the geographical regions where the test is performed (e.g. polyclonal stimulation due to parasitic infections in tropical countries).