Epidemiology of human T-lymphotropic virus type II (HTLV-II) infection in Spain

The human T-lymphotropic virus type II (HTLV-II) has recently been associated with the genesis of some subacute neurological syndromes and, rarely, with atypical T-lymphoid malignancies. The virus is endemic in some Amerindian and African tribes, and among intravenous drug users (IDUs) in North America and Europe. Given that HTLV-II is transmitted by the same routes as other human retroviruses, the screening of antibodies to HTLV-II in blood donors has became a matter of controversy in some countries. Herein, we describe the clinical, epidemiological and virological features of 113 individuals with HTLV-II infection identified in Spain up to September 1995. Most of them (94/113; 83%) were male, and all but seven were natives. Four were African immigrants living in Madrid and 3 had been born in other European countries. All but six subjects were IDUs, and sexual transmission of HTLV-II and transfusion were involved in five and one individual, respectively. Eighty-four percent of the IDUs infected with HTLV-II were co-infected by HIV-1 (93/107). Clinical manifestations potentially linked to HTLV-II were absent, although an IDU male co-infected by HIV-1 and HTLV-II developed a severe non-inflammatory proximal myopathy. In conclusion, HTLV-II infection is present in Spain, mainly among IDUs, with a growing incidence and a current overall prevalence of 2.0 percent.The members of the HTLV Spanish Study Group are listed in the Appendix.     

Human T-Lymphotropic Virus Type II in Japan

Serum specimens were assayed for human T-lymphotropic virus type II (HTLV-II) infection in 1,500 individuals known to be seropositive for HTLV-I and 30,000 blood donors in Japan. All HTLV-I-positive individuals were negative for HTLV-II. However, one of the blood donors was clearly seropositive for HTLV-II. Further, the donor was shown to be positive for HTLV-IIb. Here we report at least one case with HTLV-II in Japan and discuss the origin of the infection.     

Lack of evidence of circulating retroviral antibodies in patients with classic Hodgkin's disease

Because of the T-cell abnormalities observed in Hodgkin's disease and the growing number of Hodgkin's disease cases observed in association with the acquired immunodeficiency syndrome (AIDS), concern has been expressed that a retrovirus may be the primary cause of Hodgkin's disease. We examined plasma specimens from 17 patients with Hodgkin's disease that were drawn in 1979. Because serum containing antibodies to either human T-lymphotropic virus type I (HTLV-I) or HTLV-II precipitate the major core protein, p24, of HTLV-I, lack of reactivity to HTLV-I p24 in all the specimens demonstrated absence of antibodies to HTLV-I or -II. None of the specimens was reactive to human immunodeficiency virus type 1 (HIV-1) by ELISA. None of the specimens were reactive on Western blot assays for HTLV-I or -II or HIV-1. Lack of evidence of cross-reacting antibodies to prototype strains of those retroviruses in specimens drawn before the AIDS epidemic suggests that classic Hodgkin's disease is not the result of infection with one of the known human lymphocytotropic retroviruses or a closely related agent.     

A rapid and sensitive method of identification of HTLV-II subtypes

There are 2 subtypes of human T-cell lymphoma/ leukemia virus type II (HTLV-II), A and B. HTLV-II is increasingly associated with rare forms of lymphocytic neoplasia and a neurodegenerative disorder, characterized by hyperspasticity and ataxia. We have used PCR to amplify, clone and sequence 140 bp of the pol gene from many isolates of HTLV-IIA and HTLV-IIB from around the world. Analysis of these and other published sequences established that all HTLV-IIA sequences contained a unique Hinf I site and all HTLV-IIB sequences a unique Mse I site. A rapid and specific oligomer restriction (OR) assay was developed utilizing the primer pair SK110/SK111 and subsequent digestion with these enzymes. Concordance between sequenced and OR-based subtyping of DNA amplified by PCR was absolute among 22 HTLV-II isolates tested. Further OR or sequence analyses on an additional 30 other isolates indicated that the majority of North American non-indian HTLV-II isolates were subtype A, while all Paleo-Amerindian samples, including those from the Seminole of Florida; the Guaymi from Panama; and the Toba, Chorote, Wichi, and Chulupe of Argentina, belonged to subtype B. The SK110/SK111 PCR-OR format should facilitate molecular epidemiology studies of HTLV-II infection and allow for subtype stratification in assessing the sensitivity and specificity of HTLV detection formats and HTLV-II disease association. © 1995 Wiley-Liss, inc.     

Low prevalence of flower cells in U.S.A. blood donors infected with human T-lymphotrophic virus types I and II

Large lymphocytes with basophilic cytoplasm and cleaved/cerebriform nuclei called flower cells have been described in human T-lymphotrophic virus type I (HTLV-I) seropositive individuals and may be precursors of adult T-cell leukaemia (ATL). A cohort of 546 HTLV-seropositive former blood donors, 32 HTLV-positive sexual partners of these donors and 799 HTLV-seronegative controls has been followed as part of the Retrovirus Epidemiology Donor Study. A novel methodology was developed to systematically review peripheral blood slides from these subjects for HTLV-related lymphocyte abnormalities, using an algorithm based on morphologic features to objectively identify flower cells. The algorithm included: absence of azurophil granules; nuclear chromatin condensation; cell size >1.5 small lymphocytes; nuclear to cytoplasmic ratio >80%; and presence of nuclear folding/lobulation. Peripheral slides from subjects were screened by a medical technologist blinded to HTLV status. 6.8% of HTLV-I subjects (P = 0.0001 versus seronegatives), 0.9% of HTLV-II subjects and 1.1% of seronegatives were confirmed to have cells classified as flower cells by two haematologists using objective criteria, and blinded to serostatus. Despite the higher prevalence of flower cells in HTLV-I positives, no clinical correlations were found. Longitudinal follow-up may yield higher rates of cellular abnormalities as the sequelae of HTLV infection develop.     

Transformation of Animal Cells with Human T-Cell Leukemia Virus Type II

Human T-cell leukemia virus type II (HTLV-II) was tested for its ability to transform normal animal cells. The HTLV-II-infected human T-cell line, HTLV-IIA was lethally X-irradiated and cocultivated with normal leukocytes of rabbit and crab-eating monkey and spleen cells of hamster. The transformed cell lines, designated Ra-IIA, Si-IIA and Ham-IIA, were established. These cell lines were shown to be infected with HTLV-II by the polymerase chain reaction method combined with the digoxigenin-enzyme-linked immunosorbent assay method. These cell lines were examined for viral antigens by the indirect immunofluorescence method. Although the cytoplasma of over 90% of the cells of Si-IIA cell line was brilliantly stained, Ra-IIA and Ham-IIA cells were not stained. Electron microscopy of cells of the Si-IIA line revealed C-type virus particles in the extracellular spaces.     

Nucleotide Sequence Variation of Human T-Lymphotropic Virus Type II in Vietnam

A high rate of human T-lymphotropic virus type II (HTLV-II) infection has been documented in intravenous drug abusers (IVDAs) in South Vietnam. We have investigated the molecular characteristics of the virus and have shown that one HTLV-II subtype is predominant in Ho Chi Minh City. This molecular subtype, HTLV-IIb, was identified in a number of South Vietnamese by nucleotide sequence analysis of the long terminal repeat (LTR) region. HTLV-IIa was not found. These findings suggest that HTLV-IIb is endemic in IVDAs in South Vietnam, although IVDAs in urban areas in North America are predominantly infected with HTLV-IIa.     

Development of a supersensitive polymerase chain reaction method for human T lymphotropic virus type II (HTLV-II) and detection of HTLV-II proviral DNA from blood donors in Japan

A supersensitive polymerase chain reaction procedure was developed to detect human T-lymphotropic virus type II (HTLV-II) proviral genome. Six primer pairs covering the various regions of HTLV-II were compared and selected on the basis of specificity and sensitivity. Among them, one primer pair of the pol region of HTLV-II (II pol) was able to amplify and detect even 0.1 fg of the cloned plasmid HTLV-II DNA (seven copies) by regular ethidium bromide staining on polyacrylamide gel. By using this procedure, we screened 189 HTLV-I seropositive blood donors from Yamaguchi and Fukuoka Red Cross Blood Centers, Japan. There were four positive samples detectable with the HTLV-II-specific pol primer pair, as well as with the HTLV-I tax primer pair. The amplified DNAs of two specimens were cloned and sequenced. The sequences of the HTLV-I tax region from both specimens were identical to that of HTLV-I. On the other hand, those of the HTLV-II pol region were identical to that of HTLV-II, except for one base substitution in a clone from one subject. These results indicate that dual infection of HTLV-I and HTLV-II in the same persons occurs among Japanese blood donors.     

Detection of HTLV-II-seropositive Blood Donors in South Vietnam but Not in North Vietnam

Approximately 1% (4/500) of blood donors exhibited seropositivity for HTLV-II in South Vietnam, but none (0/500) did in North Vietnam. Further, all individuals seropositive for HTLV-II were intravenous drug abusers who were seronegative for HIV-1 and HTLV-I. These findings suggest that HTLV-II infection may be specifically prevalent in drug abusers in South Vietnam.