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Biomedical subjects

A Vallejo

Publications and source records attributed to A Vallejo.

At least 37 records · Page 2Linked to original sources
PubMed1996

Epidemiology of human T-lymphotropic virus type II (HTLV-II) infection in Spain. HTLV Spanish Study Group.

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-I (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.

Adult↗
PubMed1996

Development of a multiplex PCR assay for the simultaneous detection and discrimination of HIV-1, HIV-2, HTLV-I and HTLV-II.

BACKGROUND: Multiplex polymerase chain reaction (PCR) has been established as a general technique for the simultaneous amplification of different target sequences. Uses of multiplex include pathogens identification, linkage analysis and genetic disease diagnosis. The high sensitivity of PCR may produce false-positive results due to contamination with previously amplified material. OBJECTIVES: To develop a multiplex PCR technique that can simultaneously detect and discriminate human immunodeficiency virus types 1 and 2 (HIV-1/2) and human T-lymphotropic virus types 1 and 2 (HTLV-I/II) proviral sequences. Such a method should incorporate a system that prevents the occurrence of false-positive results. STUDY DESIGN: Combinations of four primer pairs, one for each retrovirus, were assayed in order to determine the combination of oligonucleotides as well as the PCR conditions that yield the most specific and sensitive coamplification of proviral sequences. To prevent contamination with DNA from previous PCR amplifications, the uracil N-glycosylase (UNG) system was incorporated into the coamplification format. RESULTS: A combination of primer pairs from the gag region of HIV-1, env of HIV-2, pol of HTLV-I and tax of HTLV-II yielded specific and sensitive coamplification of proviral sequences. The UNG system was incorporated and shown to be efficient in the degradation of contaminating DNA. In the evaluation of a serologically well established panel of singly and dually infected individuals, the assay detected 20/22 HIV-1, 8/10 HIV-2, 8/8 HTLV-I and 8/8 HTLV-II infections.

Cell Line↗
PubMed1996

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.

Adolescent↗
PubMed1995

[HTLV-I infection in Spain. Analysis of 24 cases identified until November, 1994. Spanish Group for the Study of HTLV-I/II)].

BACKGROUND: HTLV-I is a human retrovirus which has been implicated in the genesis of tropical spastic paraparesia (TSP), adult T-cell leukemia (ATL) and some patients with uveitis, subacute arthropathies and lymphocytary alveolitis. The virus is endemic in some zones of the Caribbean countries, Japan, subsaharian Africa, Middle East and Melanesia. Given that HTLV-I is transmitted by similar routes as HIV, anti-HTLV-I antibody screening is carried out in blood donors in some countries. METHODS: The clinical, epidemiologic and virologic characteristics of the patients with HTLV-I infection identified in Spain up to November 1994 are described. RESULTS: Twenty-four Spanish residents have been identified with HTLV-I infection including 16 Spaniards and 8 immigrants from endemic areas. Thirteen (53%) are males and 11 (47%) females. Most of the persons born in Spain (12/16; 75%) have lived in endemic areas or have maintained sexual relations with natives of them. Four patients were diagnosed with TSP, three with ATL and another with lymphomatoid granulomatosis and angiocentric T-cell lymphoma. The remaining patients were asymptomatic at the time of diagnosis. Two HTLV-I carriers were identified on blood donation. CONCLUSIONS: HTLV-I infection is present in Spain being found in Spanish natives and, to a lesser degree, in immigrants from endemic areas. It is therefore recommendable to analyze the cost-benefit of anti-HTLV-I screening in blood donors.

Adult↗
PubMed1995

[HTLV-II infection in Spain. Analysis of 113 cases identified until November, 1994. Spanish Group for the Study of HTLV/I/II].

BACKGROUND: HTLV-II is a human retrovirus considered to be responsible for the genesis of some lymphoproliferative and neurologic syndromes. The virus is endemic in some Amerindian and African tribes as well amongst injecting drug addicts (IDA) in North America and Europe. METHODS: The clinical, epidemiologic and virologic characteristics of the patients with HTLV-II infection identified in Spain up to November 1994 are described. RESULTS: One hundred thirteen subjects have been identified with HTLV-II infection in Spain with 4 being African immigrants residing in Madrid and the remaining being IDA from other European countries. Most were males (94/113; 83%). All were IDA except six (5 had acquired the infection by sexual contact and one by blood transfusion). Most of the IDA infected with HTLV-II were coinfected with HIV-1 (93/113; 83%). No patient showed clinical manifestations attributable to HTLV-II infection although one drug addict male coinfected with HIV-1 and HTLV-II developed a non-inflammatory proximal myopathy. CONCLUSIONS: Infection by HTLV-II is present in Spain and affects with preference to injecting drug addicts. It has been shown to be of growing incidence with a current global prevalence of 2% in IDA.

Adult↗
PubMed1995

Typing human T-cell lymphotropic virus (HTLV-I and HTLV-II) by nested polymerase chain reaction: application to clinical specimens.

Human T-cell lymphotropic virus type I and II provirus DNA was detected by polymerase chain reaction (PCR). MT-2 (HTLV-I infected), C3/44 Mo (HTLV-II infected) cell lines and peripheral blood mononuclear cells (PBMNC) from HTLV seropositive samples were used. The procedure consists of first amplification which detects both HTLV-I and HTLV-II, and a second amplification (nested-PCR) to discriminate between the two viruses and to improve sensitivity. Optimal conditions of MgCl2 concentration and annealing temperature were found for maximal amplification and specificity. This method was used for the amplification of conserved regions of pol and env genes. 1.5 pg of MT-2 and 5 pg of C3/44 Mo cell line DNAs were detected using nested-PCR and liquid hybridization in the pol system. The env system could detect 1.5 pg of MT-2 and 1.5 pg of C3/44 Mo cell lines DNAs using nested-PCR and liquid hybridization. The pol system can type both HTLV-I and HTLV-II in only two steps without the use of type-specific radiolabeled probes. Furthermore, this method can detect and discriminate the two viruses in one step PCR using the primers used in the nested-PCR. Nevertheless, there is a decrease in sensitivity of 100-fold. The results of five seropositive samples confirmed by Western blot are compared with PCR. PCR typed one of these samples as HTLV-I and the rest as HTLV-II. This technique is useful in cases such as window period, perinatal studies and when serologic results are not satisfactory.

Base Sequence↗
PubMed1994

[Isolation, sequencing and ultrastructure of HTLV-I and HTLV-II retroviruses. Presence of the HTLV-II subtype b among Spanish intravenous drug addicts].

BACKGROUND: Six cases of HTLV-I/II infection were selected for isolation and characterization of these retrovirus. METHODS: Detection of anti-HTLV antibodies was carried out by enzyme immunoassay (EIA), immunofluorescence (IFI), and Western blot (WB). Analysis of proviral DNA was performed by PCR. Viral culture and partial sequencing of the pol and pX genes were carried out. Electron microscopy morphologically characterized the viral particles. RESULTS: Serologic study demonstrated four cases of HTLV-II, one of HTLV-I, and one non-typeable HTLV infections. This last case was confirmed as positive for HTLV-II by PCR. Five new HTLV-II and one HTLV-I infected cell lines have been established by co-culture. Electron microscopy allowed morphologic characterization of the viral particles found in the infected cells. The sequence of the five strains of HTLV-II was identical demonstrating a divergence of 0.49% in the pX region and of 4.5% in the pol region compared with the HTLV-II Mo prototype. Comparison of these sequences with those corresponding to different strains of HTLV-II isolates from American Indians (subtypes b) suggest that these Spanish strains are more closely related with the subtype b than with the subtype a (HTLV-II Mo). Genetic variability study did not reveal any change in the sequence of these stains suggesting that the variability of these retroviruses in very infrequent in the regions studied. The analysis of the pol region of the HTLV-I strain demonstrated a divergence of 3.4% with respect to the sequence of the ATK-1 prototype (Japan) and of 1.7% of the strain HS-35 (Caribbean) showing a greater relation with the Caribbean strains than with those from Japan. CONCLUSIONS: The presence of HTLV-II subtype has been confirmed among intravenous drug addicts in Spain. Isolation and characterization of the HTLV-I strain demonstrated that this also circulating around Spain despite its South American origin.

Base Sequence↗