Development of a novel multiplex digital PCR-based method for the detection of HTLV-1 proviral deletion.

The human T-cell leukemia virus type 1 (HTLV-1), a retrovirus, integrates into host DNA and causes adult T-cell leukemia/lymphoma (ATL) in some individuals. Two types of defective proviruses, Type 1 and Type 2, are often observed in ATL cells. Here, we developed a 3-plex digital PCR (dPCR) method to detect HTLV-1 proviral deletions by comparing the ratios of copy numbers quantified using specific primer-probes for the LTR, pol, and pX regions.

Plasma vitamin D levels are correlated with the pathogenesis of human T-cell leukemia virus type 1-associated diseases.

The active form of vitamin D (VD) exerts hormonal effects by regulating the expression of genes involved in T-cell activity, cell differentiation, and proliferation. Human T-cell leukemia virus type 1 (HTLV-1) is a causative agent of life-threatening diseases, adult T-cell leukemia (ATL) and HTLV-1-associated myelopathy (HAM). Among ATL patients, hypercalcemia is one of the most serious complications due to bone resorption.

Repeated apheresis donations cause important iron deficiency in male Japanese donors.

Background And Objectives: In Japan, apheresis donation of plasma is allowed to a maximum of 24 times a year, and plateletpheresis are counted as two plasmapheresis donations. Diversion of the initial blood flow is conducted for all donations, and additionally, blood remaining in apheresis machine circuit is lost. Here, we aimed to investigate on the health impact of frequent apheresis donations, as measured by the serum ferritin (sFer).

Iron deficiency among Japanese whole-blood donors measured by serum ferritin.

Background And Objectives: A more restrictive blood donation criterion has been applied in Japan, with a maximum volume of whole blood (WB) donation of 400 mL, allowing twice a year for female donors and thrice a year for male donors. However, iron deficiency was as high as 20.5% among female donors prior to donation, increasing to 37.

Detection of early phase human T-cell leukemia virus type 1 and 2 infection with an improved confirmatory test.

Background: Human T-cell leukemia virus type 1 (HTLV-1) is a blood-borne virus, and mandatory testing of donated blood for HTLV-1 antibodies has been adopted by Japanese Red Cross blood centers since 1986. A confirmatory line immunoassay was initiated in 2019 for individuals who were seroreactive in the screening test. This decreased the incidence of indeterminate individuals, however, donors with indeterminate results are not informed of their HTLV-1 seroreactivity and they can continue to donate blood.

Selection of Cord Blood Unit by CD34 Cell and GM-CFU Numbers and Allele-Level HLA Matching in Single Cord Blood Transplantation.

In Japan, only single-unit cord blood transplantations (CBTs) are typically performed, and their number has increased over the last 23 years, with ongoing improvement in results. In most cases, CBTs with multiple HLA mismatches are used, owing to a low HLA barrier, and lower engraftment rate is a problem that must be overcome. Here, as part of an effort to improve guidelines for the selection and processing of CB units for transplantation, we sought to assess the present status of CBT in Japan and to elucidate factors contributing to the favorable outcomes, focusing in particular on selection by cell components of CB unit and HLA allele matching.

A decrease in newly diagnosed patients with adult T-cell leukemia/lymphoma in Kagoshima, a highly endemic area of HTLV-1 in southwestern Japan.

Adult T-cell leukemia/lymphoma (ATL) is a peripheral T-cell malignancy caused by human T-cell leukemia virus type-I (HTLV-1). This study investigated whether the number of newly diagnosed patients with ATL is decreasing in the background of a declining number of individuals infected by HTLV-1 in Kagoshima, Japan, one of the most endemic areas of HTLV-1 in the world. We retrospectively analyzed the number of newly diagnosed patients with ATL between January 2001 and December 2021 in three major hospitals.

Increasing horizontal transmission of human T-cell leukemia virus type 1 in adolescents and young adults in Japan.

Background: Human T-cell leukemia virus type 1 (HTLV-1) is a causative agent of the life-threatening diseases, adult T-cell leukemia/lymphoma and HTLV-1-associated myelopathy. Following implementation of antenatal screening in Japan, novel transmission of HTLV-1 in adolescent and adult generations is expected to replace vertical transmission as the main route for transmission.

Objectives: To obtain the current status of HTLV-1 horizontal infection and to assess the fluctuation of transmission occurring among adolescents and adults in Japan.

High Prevalence of HTLV-1 Carriers Among the Elderly Population in Kagoshima, a Highly Endemic Area in Japan.

Japan is one of the world's highly endemic areas for human T cell leukemia virus type 1 (HTLV-1), and it is known that the infection rate of HTLV-1 increases with age. The infection rate among the elderly has been estimated based on data from blood donors under the age of 65, and the actual number and rate of infection among the elderly are unknown. Data of 26,090 preoperative HTLV-1 screening tests conducted at Kagoshima University Hospital from 2001 to 2020, including 2726 HTLV-1-positive patients, were used for calculating the decadal infection rates for the year of birth.

Human T-Cell Leukemia Virus Type 1 Infection Is a Risk Factor for Atherosclerosis.

Background: Infection, such as by human immunodeficiency virus (HIV), has been reported to cause atherosclerosis by inducing inflammation. Because human T-cell leukemia virus type 1 (HTLV-1) is a retrovirus, as is HIV, we investigated the possible influence of HTLV-1 on the pathogenesis of atherosclerosis by use of established atherosclerosis parameters.

Methods: The study was done on Iki Island, Fukuoka, an area endemic for HTLV-1.

Estimation of the window period of human T-cell leukemia virus type 1 and 2 tests by a lookback study of seroconverters among Japanese voluntary blood donors.

Background: Japan is endemic for human T-cell leukemia virus type 1 (HTLV-1), and the horizontal transmission of HTLV-1 is often reported. However, the window period (WP) for serologic or molecular screening is unclear.

Study Design And Methods: Results for anti-HTLV-1 screening and confirmatory tests obtained from 648 591 repeated blood donors in the Kyushu district, one of the most endemic areas of HTLV-1 in the world, were evaluated.

Establishment of a novel diagnostic test algorithm for human T-cell leukemia virus type 1 infection with line immunoassay replacement of western blotting: a collaborative study for performance evaluation of diagnostic assays in Japan.

Background: The reliable diagnosis of human T-cell leukemia virus type 1 (HTLV-1) infection is important, particularly as it can be vertically transmitted by breast feeding mothers to their infants. However, current diagnosis in Japan requires a confirmatory western blot (WB) test after screening/primary testing for HTLV-1 antibodies, but this test often gives indeterminate results. Thus, this collaborative study evaluated the reliability of diagnostic assays for HTLV-1 infection, including a WB-based one, along with line immunoassay (LIA) as an alternative to WB for confirmatory testing.

Clinical significance of soluble CADM1 as a novel marker for adult T-cell leukemia/lymphoma.

Adult T-cell leukemia/leukemia (ATLL) is an aggressive peripheral T-cell malignancy, caused by infection with the human T-cell leukemia virus type 1 (HTLV-1). We have recently shown that cell adhesion molecule 1 (CADM1), a member of the immunoglobulin superfamily, is specifically and consistently overexpressed in ATLL cells, and functions as a novel cell surface marker. In this study, we first show that a soluble form of CADM1 (sCADM1) is secreted from ATLL cells by mainly alternative splicing.

Erythrocytes lacking the Langereis blood group protein ABCB6 are resistant to the malaria parasite .

The ATP-binding cassette transporter was recently discovered to encode the Langereis (Lan) blood group antigen. Lan null individuals are asymptomatic, and the function of ABCB6 in mature erythrocytes is not understood. Here, we assessed ABCB6 as a host factor for malaria parasites during erythrocyte invasion.

Development of reference material with assigned value for human T-cell leukemia virus type 1 quantitative PCR in Japan.

Quantitative PCR (qPCR) of human T-cell leukemia virus type 1 (HTLV-1) provirus is used for HTLV-1 testing and for assessment of risk of HTLV-1-related diseases. In this study, a reference material was developed for standardizing HTLV-1 qPCR. Freeze-dried TL-Om1 cells diluted with Jurkat cells were prepared and an assigned value for proviral load (PVL) of 2.

Fine-scale geographic clustering pattern of human T-cell leukemia virus type 1 infection among blood donors in Kyushu-Okinawa, Japan.

Human T-cell leukemia virus type I (HTLV-1) infection is endemic in Japan, particularly clustered in the southwestern district, Kyushu-Okinawa, which consists of eight prefectures that further consist of 274 municipalities. However, no information is available about the fine-scale distribution of HTLV-1 infection within Kyushu-Okinawa. To assess the municipal-level distribution of people with HTLV-1 infection in Kyushu-Okinawa, we performed a cross-sectional study using a fine-scale geographic information system map based on HTLV-1 screening test results from the Japanese Red Cross database from September 2012 to February 2014.

The B allele with a 5·8 kb deletion in intron 1 of the ABO gene is the major allele in Japanese individuals with B and A B phenotypes.

B and A B phenotypes are the most frequent ABO variants in the Japanese population. The B antigen on B red blood cells is only detectable by adsorption and elution tests, and plasma B-transferase activity is usually detected at half or less levels compared with that of common B. Recently, a B allele lacking an erythroid cell-specific transcription enhancer in intron 1 of the ABO gene was identified from individuals with B and A B phenotypes, which could explain the unique serologic properties of B .

Proviral Features of Human T Cell Leukemia Virus Type 1 in Carriers with Indeterminate Western Blot Analysis Results.

Western blotting (WB) for human T cell leukemia virus type 1 (HTLV-1) is performed to confirm anti-HTLV-1 antibodies detected at the initial screening of blood donors and in pregnant women. However, the frequent occurrence of indeterminate results is a problem with this test. We therefore assessed the cause of indeterminate WB results by analyzing HTLV-1 provirus genomic sequences.

Interactions between inflammatory gene polymorphisms and HTLV-I infection for total death, incidence of cancer, and atherosclerosis-related diseases among the Japanese population.

Background: An increased risk of total death owing to human T-lymphotropic virus type-I (HTLV-I) infection has been reported. However, its etiology and protective factors are unclear. Various studies reported fluctuations in immune-inflammatory status among HTLV-I carriers.

Standardization of Quantitative PCR for Human T-Cell Leukemia Virus Type 1 in Japan: a Collaborative Study.

Quantitative PCR (qPCR) analysis of human T-cell leukemia virus type 1 (HTLV-1) was used to assess the amount of HTLV-1 provirus DNA integrated into the genomic DNA of host blood cells. Accumulating evidence indicates that a high proviral load is one of the risk factors for the development of adult T-cell leukemia/lymphoma and HTLV-1-associated myelopathy/tropical spastic paraparesis. However, interlaboratory variability in qPCR results makes it difficult to assess the differences in reported proviral loads between laboratories.

Malaria. A forward genetic screen identifies erythrocyte CD55 as essential for Plasmodium falciparum invasion.

Efforts to identify host determinants for malaria have been hindered by the absence of a nucleus in erythrocytes, which precludes genetic manipulation in the cell in which the parasite replicates. We used cultured red blood cells derived from hematopoietic stem cells to carry out a forward genetic screen for Plasmodium falciparum host determinants. We found that CD55 is an essential host factor for P.