Although the mortality rate due to hepatocellular carcinoma (HCC) has been gradually decreasing in Japan, approximately 30 000 people died of HCC in 2016. In 2007, the dominant etiology was ...persistent hepatitis C virus (HCV) infection, which accounted for 65% of total HCC deaths, and 15% of cases were due to chronic hepatitis B virus (HBV) infection. In managing chronic HBV and HCV infection, it is critically important to know the exact number of infected individuals in a particular country, which then assists in evaluating medical and financial needs in the foreseeable future. Therefore, from an epidemiological perspective, we estimated the numbers of HBV and HCV carriers in four categories: (i) undiagnosed carriers; (ii) carriers who were already hospitalized as patients or were receiving outpatient medical attention; (iii) diagnosed carriers who had not consulted any medical facility, or had discontinued consultation; and (iv) newly infected carriers. From these estimates we determined the current HBV and HCV burden and then reviewed the existing countermeasures for their prevention and control in Japan. While continuing the surveillance on the dynamics of hepatitis virus infections linked with preventive measures against hepatitis virus infection, it is crucially important to promote appropriate measures for each of the four groups of hepatitis virus carriers in society.
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BFBNIB, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK
Summary Background Human T-lymphotropic virus 1 (HTLV-1) infection has an especially high prevalence in Japan. Transmission has been confirmed in infancy through breastfeeding; however, little is ...known about the epidemiological aspects of new HTLV-1 infections later in life. We aimed to estimate the nationwide annual number of new HTLV-1 infections among adolescents and adults in Japan. Methods In this retrospective cohort analysis, we assessed new HTLV-1 infections of repeat blood donors aged 16–69 years between Jan 1, 2005, and Dec 31, 2006, in the Japanese Red Cross Blood Centres database. We used results of antibody tests done in repeat blood samples collected until Dec 31, 2011, to assess the number who seroconverted to HTLV-1. We calculated the incidence density by dividing the number of seroconverters by the number of person-years of follow-up, and then extrapolated densities to regional populations to estimate the annual number of new HTLV-1 infections. Findings We included 3 375 821 HTLV-1-seronegative blood donors (2 100 915 men and 1 274 906 women). Within a median follow-up of 4·5 years (IQR 2·3–5·8), 532 people (204 men and 328 women) had seroconverted. The incidence density was significantly higher in women (6·88 per 100 000 person-years; 95% CI 6·17–7·66) than in men (2·29 per 100 000 person-years; 95% CI 1·99–2·62; p<0·0001). The estimated annual number of new HTLV-1 infections was 4190 (95% CI 4064–4318) with 975 (914–1038) infections in men and 3215 (3104–3328) in women. Interpretation New HTLV-1 infections in adolescents and adults are an important public health concern in Japan and preventive strategies are needed to reduce new transmission. Funding Ministry of Health, Labour, and Welfare of Japan; Japan Agency for Medical Research and Development.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Abstract
Tetanus is a fatal disease caused by tetanus neurotoxin (TeNT). TeNT is composed of a light chain (Lc) and a heavy chain, the latter of which is classified into two domains, N-terminus Hn ...and C-terminus Hc. Several TeNT-neutralizing antibodies have been reported, but it remains unclear which TeNT domains are involved in neutralization. To further understand the mechanism of these antibodies, we isolated TeNT-reactive human antibody clones from peripheral blood mononuclear cells. We then analyzed the reactivity of the isolated antibody clones to each protein domain and their inhibition of Hc-ganglioside GT1b binding, which is critical for TeNT toxicity. We also investigated the TeNT-neutralizing ability of isolated antibody clones and showed that an Hn-reactive clone protected strongly against TeNT toxicity in mice. Furthermore, combination treatment of Hn-reactive antibody clones with both Hc-reactive and TeNT mix (the mixture of Hc, Hn, and Lc proteins)–reactive antibody clones enhanced the neutralizing effect. These results indicated that antibody clones targeting Hn effectively neutralized TeNT. In addition, the use of a cocktail composed of Hc-, Hn-, and TeNT mix–reactive antibodies provided enhanced protection compared to the use of each antibody alone.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
This study was aimed to precisely estimate the prevalence of hepatitis B surface antigen (HBsAg) and anti-hepatitis C virus antibody (anti-HCV) stratified by sex and birth year in Japan.
Three ...large-scaled cohorts: first-time blood donors, periodic health check-up, and comprehensive health check-up with lifestyle education (Ningen dock) were used for pooled prevalence of HBsAg and anti-HCV using meta-regression.
Trends of birth year-specific prevalence of HBsAg and anti-HCV among the three cohorts were similar to one another, while birth year-specific pooled prevalence of HBsAg peaked in the 1941-1950 birth cohort. Prevalence of anti-HCV showed a decreasing trend by birth year.
We could estimate the pooled prevalence of HBsAg and anti-HCV based on nationwide data. The results can be used as reference data for various countermeasures for hepatitis eradication.
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FFLJ, NUK, ODKLJ, UL, UM, UPUK
The incidence of hepatitis A virus (HAV) infection has declined significantly worldwide, including in Japan. A nationwide seroepidemiological study on hepatitis A in Japan has taken place almost ...every 10 years since 1973, and the last study was performed in 2003. In the present study, we describe the latest seroepidemiological pattern of hepatitis A in Japan using 7867 serum specimens obtained from healthy individuals collected between 2013 and 2017, approximately 10 years after the last study. Among them, 223 were anti‐HAV positive. About 68% of individuals aged 60 years and older had anti‐HAV antibodies, whereas only 1.1% of those aged below 60 years old had immunity; thus, almost all individuals younger than 60 years of age were HAV susceptible. In comparison with previous investigations, the susceptible population has increased and aged. According to data from the National Epidemiological Surveillance of Infectious Diseases (NESID) program, between 1989 and 2016, the proportion of patients with hepatitis A aged 60 years and older continuously increased with each year. The NESID data also suggested that recently, typical large foodborne outbreaks of hepatitis A have become rare, and cases tend to be reported among at‐risk groups; overseas travelers contributed to 25% of hepatitis A cases, and in 2018, the first nationwide hepatitis A outbreak that affected mostly men who have sex with men was reported. The purpose of this study was to determine the current status of HAV infection in Japan, based on both seroepidemiology and the national surveillance data from the NESID.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Background
The current prevalence of cytomegalovirus (CMV) in Japan and the risk of CMV transfusion transmission are unknown in the era of seronegative leukoreduced blood components.
Study Design and ...Methods
We measured CMV‐specific immunoglobulin (Ig)M and IgG in 2400 samples of whole blood collected from 12 groups of blood donors categorized by sex and age at 10‐year intervals from their teens to their 60s. We also tested for CMV DNA using polymerase chain reaction in the cellular fractions of all samples.
Results
We found that 76.6% of blood donors were CMV seropositive. The seroprevalences among donors in their 20s and 30s were 58.3 and 73.3%, respectively. We detected CMV DNA in the cellular fraction of 4.3% of samples from donors in their 60s and in 1.0% of samples from donors younger than 60 years. None of the 562 seronegative samples was DNA positive. Furthermore, 14% of DNA‐positive samples also contained DNA in the plasma fraction, and two of five such samples were derived from donors in their 60s. Leukoreduced plasma components derived from donations with CMV DNA in plasma samples also contained a relevant amount of CMV DNA.
Conclusion
The seroprevalence of CMV among Japanese blood donors of child‐bearing age has not changed over the past 15 years. Latent CMV becomes reactivated more frequently among elderly donors than among younger donors. A proportion of them have free CMV DNA in their plasma fraction, which could not be diminished by leukoreduction. The risk of transfusion‐transmitted CMV infection in blood with plasma CMV DNA should be determined.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
BACKGROUND
Transfusion‐transmitted bacterial infections (TTBIs) often have serious consequences for patients. The Japanese Red Cross (JRC) has not implemented culture screening for platelet ...concentrate (PC), but it has maintained a shelf life of 85 hours for PC.
STUDY DESIGN AND METHODS
The JRC collected reports of suspected TTBI and investigated causal relationships using PC samples and patient blood samples. PCs showing apparent abnormalities were retrieved and cultured and analyzed for bacterial growth.
RESULTS
The JRC analyzed 86 samples available from 135 transfused PCs with suspected TTBIs that were collected over the past 12 years; 17 (19.8%) were culture‐positive. One, 6, and 10 TTBIs developed in patients on Days 1, 2, and 3 after PC collection, respectively. Assuming that PC is transfused on the day of issue, the TTBI risk was fourfold higher on Day 3 than on Day 2, after adjusting the TTBI incidence for the number of PCs issued per day. Compared with the model of issuing all PCs on Day 3, issuing PCs with the current distribution of storage time could have decreased the TTBI incidence by 56%. During the past 8 years, the JRC retrieved 960 PC units because of apparent abnormalities, 2.8% of which were culture‐positive.
CONCLUSION
The short shelf life of PC is associated with a low incidence of reported TTBIs, more than half of which occurred on Day 3 relative to earlier time points. Visual inspection of PC before transfusion is crucial in detecting bacterially contaminated PC despite its low positive predictive value.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
BACKGROUND
Our previous study showed that ultraviolet C (UVC) from xenon (Xe) flash without any photoreactive compounds inactivated bacteria in platelet concentrates (PCs) with less damage to ...platelets (PLTs) as compared with Xe flash containing ultraviolet A, ultraviolet B, and visible light. Here, we report a UVC irradiation system for PCs under flow conditions consisting of a flow path–irradiation sheet, a peristaltic pump, and a collection bag.
STUDY DESIGN AND METHODS
Platelet concentrates containing Ringerʼs solution (R‐PCs) inoculated with bacteria were injected into a flow path sheet using a peristaltic pump, being irradiated with UVC from Xe flash. The quality of the irradiated PCs containing platelet additive solution (PAS‐PCs) was assessed based on PC variables, PLT surface markers, and aggregation ability.
RESULTS
Streptococcus dysgalactiae (12 tests) and Escherichia coli (11) were all negative on bacterial culture, while Staphylococcus aureus (12) and Klebsiella pneumoniae (14) grew in one and two R‐PCs, respectively. Bacillus cereus spores were inactivated in 7 of 12 R‐PCs. PC variables became significantly different between irradiated and nonirradiated PAS‐PCs. P‐selectin, first procaspase‐activating compound (PAC‐1) binding, and phosphatidylserine increased by irradiation. Aggregability stimulated by adenosine diphosphate, collagen, or thromboxane A2 increased in the irradiated PAS‐PCs, while that by thrombin became smaller compared with nonirradiated controls.
CONCLUSION
This newly developed system inactivated bacteria including spores in R‐PCs. PAS‐PCs irradiated by this system retained acceptable in vitro quality and aggregability. Usage of a peristaltic pump instead of agitator during irradiation may enable this system to be directly combined with an apheresis blood cell separator.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
BACKGROUND
The classification of many new cases of hepatitis virus infection as overt hepatitis does not reflect the true incidence of infection because the disease takes an asymptomatic course in ...some cases. In this retrospective cohort study, we aimed to estimate the incidence rates of new hepatitis C virus (HCV) infections among the blood donors.
STUDY DESIGN AND METHOD
A 5‐year retrospective cohort study was conducted to estimate the incidence rates by using the medical records of the blood donors between 2008 and 2013 for HCV infection. HCV seroconversions were investigated using a chemiluminescent enzyme immunoassay and then confirmed by nucleic acid amplification tests.
RESULTS
The incidence rate of HCV infection was 0.40 per 100,000 person‐years (95% confidence interval, 0.27–0.57) for HCV RNA seroconversion only and 7.32 per 100,000 person‐years (95% confidence interval, 6.73–7.95) if either HCV RNA or anti‐HCV seroconversion were taken into consideration. No significant difference of new HCV infections was found between the sexes.
CONCLUSION
The incidence rate of HCV infection of this study was lower than that detected in a previous 1994–2004 study in which HCV incidence was 1.86 per 100,000 person‐year, which reflects the presence of an effective blood screening system and health strategies targeting hepatitis control and prevention.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
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