Measurement of allergen-specific IgE antibodies to inhaled allergens is important for the diagnosis and risk evaluation of allergic diseases such as asthma and allergic rhinitis. This study aimed to ...elucidate the prevalence of allergen sensitization among the healthy population in Japan using serum samples stocked in the Japanese Red Cross for blood donation.
Age- and gender-stratified serum samples (n = 800) from residents in Tokyo aged 20–59 years were randomly selected from the stocked serum obtained for blood donation in 2005. Total and specific IgE antibodies to 17 inhaled allergens were measured by the ImmunoCAP method. Individuals with positive (≥0.35 UA/mL) specific IgE antibodies to at least one inhaled allergen were defined as atopic. Stocked serums from donors aged 20–29 years in Sapporo, Osaka, Fukuoka, and Okinawa (n = 200 each) were also obtained for the measurement of IgE to six common inhaled allergens, to evaluate regional differences in the rate of positivity.
Among residents in Tokyo, the prevalence of atopy was 78.0% and highest in men aged 20–29 years (94.0%), which decreased with age. The prevalence of specific IgE antibodies was highest for Japanese cedar pollen (66.8%), followed by cypress pollen (46.8%), Dermatophagoides pteronyssinus (38.3%), and moths (30.1%). Examination of IgE to Japanese cedar pollen, D. pteronyssinus, and moths identified 97.6% of atopic subjects in Tokyo. There were substantial regional differences in the prevalence of pollen IgE positivity.
This study demonstrated an extremely high prevalence of positivity in inhaled allergen-specific IgE antibodies among healthy adults in Japan.
The presence of IgG antibodies (Abs) to Aspergillus fumigatus (Af) is a crucial diagnostic criterion for allergic bronchopulmonary aspergillosis (ABPA). Although precipitation is traditionally used ...to document IgG Abs, anti-Af serum IgG levels can also be measured by enzyme immunoassay (EIA). However, there are insufficient data on the optimal cut-offs to assess diagnostic performance of the EIA method. This study aimed to determine cut-off levels of IgG binding crude Af extracts or recombinant Asp f 1 (by ImmunoCAP®) and to compare their efficacy for ABPA diagnosis with Af-precipitating Abs.
The age distribution of levels of IgG to crude extracts of Af (Af-IgG) and recombinant Asp f 1 (Asp f 1-IgG) was established using sera from 694 healthy controls (HC). Receiver operating characteristic analysis for Af-IgG and Asp f 1-IgG levels for the purpose of ABPA diagnosis was performed in 306 Af-sensitized asthma patients (including 49 ABPA), and cut-offs were determined.
An age-dependent decline in the levels of Af-IgG was observed in HC. Thus, cut-offs for Af-IgG levels were determined separately by age as 60 mg/L for patients aged <55 years, and 45 mg/L for those aged ≥55 years. For Asp f 1-IgG, 6.6 mg/L was set as the cut-off regardless of age. Although such IgG testing by EIA allowed a sufficiently good diagnostic performance, Af-precipitating Abs had better diagnostic applicability for ABPA.
We determined cut-offs for Af-IgG and Asp f 1-IgG measured by EIA, which can be useful in clinical settings where precipitating Abs are unavailable.
Objectives
Increasing numbers of reports have described hematopoietic improvement after iron chelation therapy in iron‐overloaded patients. These observations indicate that excess iron could affect ...hematopoiesis unfavorably. To investigate how excess iron affects hematopoiesis in vivo, we generated iron‐overloaded mice and examined hematopoietic parameters in these mice.
Methods
We generated iron‐overloaded mice by injecting 200 mg of iron dextran into C57BL/6J mice, and immature hematopoietic cells in the bone marrow were evaluated by flow cytometric analyses, colony‐forming assays, and bone marrow transplantation analyses. We also examined changes in molecular profiles of the hematopoietic microenvironment.
Results and Conclusions
Iron‐overloaded (IO) mice did not show significant defects in the hematopoietic data of the peripheral blood. Myeloid progenitor cells in the bone marrow were increased in IO mice, but the number and function of the erythroid progenitors and hematopoietic stem cells were not significantly affected. However, bone marrow transplantation from normal donors to IO recipients showed delayed hematopoietic reconstitution, which indicates that excess iron impacts the hematopoietic microenvironment negatively. Microarray and quantitative RT‐PCR analyses on the bone marrow stromal cells demonstrated remarkably reduced expression of CXCL12, VCAM‐1, Kit‐ligand, and IGF‐1 in the iron‐overloaded mice. In addition, erythropoietin and thrombopoietin levels were significantly suppressed, and increased oxidative stress was observed in the IO bone marrow and liver. Consequently, our findings indicate that excess iron can damage bone marrow stromal cells and other vital organs, disrupting hematopoiesis presumably by increased oxidative stress.
We conducted a prospective randomized study to assess the optimal postremission therapy for adult acute myeloid leukemia in patients younger than 65 years in the first complete remission. A total of ...781 patients in complete remission were randomly assigned to receive consolidation chemotherapy of either 3 courses of high-dose cytarabine (HiDAC, 2 g/m2 twice daily for 5 days) alone or 4 courses of conventional standard-dose multiagent chemotherapy (CT) established in the previous JALSG AML97 study. Five-year disease-free survival was 43% for the HiDAC group and 39% for the multiagent CT group (P = .724), and 5-year overall survival was 58% and 56%, respectively (P = .954). Among the favorable cytogenetic risk group (n = 218), 5-year disease-free survival was 57% for HiDAC and 39% for multiagent CT (P = .050), and 5-year overall survival was 75% and 66%, respectively (P = .174). In the HiDAC group, the nadir of leukocyte counts was lower, and the duration of leukocyte less than 1.0 × 109/L longer, and the frequency of documented infections higher. The present study demonstrated that the multiagent CT regimen is as effective as our HiDAC regimen for consolidation. Our HiDAC regimen resulted in a beneficial effect on disease-free survival only in the favorable cytogenetic leukemia group. This trial was registered at www.umin.ac.jp/ctr/ as #C000000157.
Hepatitis A virus (HAV) has begun to spread globally among men who have sex with men (MSM). Hepatitis E virus (HEV) also may be transmitted through sexual contact among MSM. To assess the current ...status of these viruses among MSM in Japan, the seroprevalence of both viruses using 503 plasma samples collected between 2009 and 2018 from human immunodeficiency virus (HIV)‐positive male donors who were presumed to be mainly MSM was investigated. Our results suggested that HAV may be spreading within this population, as reported elsewhere. By contrast, the spread of HEV was confirmed only among younger HIV‐positive donors.
How to select optimal cord blood (CB) remains an important clinical question. We developed and validated an index of CB engraftment, the cord blood index (CBI), which uses three weighted variables ...representing cell doses and HLA mismatches. We modeled the neutrophil engraftment time with competing events by random survival forests for competing risks as a function of the predictors: total nucleated cells, CD34, colony-forming units for granulocytes/macrophages, and the number of HLA mismatches at the antigen and allele levels. The CBI defined three groups that had different neutrophil engraftment rates at day 30 (High, 83.7% 95% CI, 79.2-88.1%; Intermediate, 77.0% 95% CI, 73.7-80.2%; Low, 68.4% 95% CI, 63.6-73.2%), platelet engraftment rates at day 60 (High, 70.4% 95% CI, 64.9-75.9%; Intermediate, 62.3% 95% CI, 58.5-66.0%; Low, 49.3% 95% CI, 44.2-54.5%), and non-relapse mortality at day 100 (High, 14.1% 95% CI, 9.9-18.3%; Intermediate, 16.4% 95% CI, 13.5-19.3%; Low, 21.3% 95% CI, 17.1-25.5%). This novel approach is clinically beneficial and can be adopted immediately because it uses easily obtained pre-freeze data of CB.
The DNA methylation inhibitor azacitidine (5-azacytidine) is used against myelodysplastic syndrome and acute myeloid leukemia, but drug resistance is an ongoing, intractable problem. To investigate ...resistance mechanisms, we generated two azacitidine-resistant cell lines, THP-1/AR and HL60/AR, and studied genetic disparities between them and their corresponding parental lines. In cells treated with azacitidine, significant mitotic variations were noted in parental cells which were absent in resistant cells, suggesting that resistance arises from negating azacitidine-mediated activation of apoptosis signaling and reestablishing G2 /M checkpoint. Importantly, both resistant cell lines have common point mutations in the uridine-cytidine kinase 2 ( UCK2 ) gene, which encodes the rate-limiting enzyme of the azacitidine activation pathway. Forced expression of mutated UCK2 in parental THP-1 cells abrogated azacitidine-induced apoptosis, whereas overexpression of wild type UCK2 in resistant THP-1/AR cells restored sensitivity to azacitidine, implying that UCK2 gene mutations perturb azacitidine activation and advance azacitidine resistance. Our study provides new insights into azacitidine resistance and establishes models useful in developing effective strategies to overcome it.
BACKGROUND
Human babesiosis is caused mainly by Babesia microti and has recently become a public health concern due to an increase in transfusion‐transmitted infection. Thus, the development of an ...antibody detection method with high specificity and sensitivity is a priority. Seroreactivity against B. microti has been reported to be highly specific not only to B. microti lineages but also to sublineages. This study aimed to elucidate the human antibody reactivity against various lineages, including US, Kobe, and Hobetsu, and sublineages (North America and East Asia) in the US lineage.
STUDY DESIGN AND METHODS
Twenty samples obtained from individuals infected with B. microti in the United States were tested for the presence of anti‐B. microti antibodies using indirect immunofluorescence assay (IFA) and Western blotting (WB) to indicate antigens of each (sub‐)lineage.
RESULTS
By IFA, 20 samples showed reactivity to the North America sublineage (titer range, 64‐4096), 16 to the East Asia sublineage (64‐512), 10 to the Kobe (64‐128), and five to the Hobetsu (64). Antibody titers to the East Asia sublineage, Kobe, and Hobetsu were significantly lower than those to the North America sublineage (p < 0.01). By WB, in parallel with the IFA results, 18 samples showed strong reactions to the North America sublineage, weak reactions to the East Asia sublineage, and near‐zero reactions to the Kobe and Hobetsu.
CONCLUSION
Human antibodies induced by B. microti infection are highly specific against B. microti lineages and sublineages with low cross‐reactivity. Developing a precise antibody detection method may require specific antigens based on B. microti lineages and sublineages.
There are few reports on HIV-1 intra-host evolutionary rate in asymptomatic treatment-naïve patients. Here, the HIV-1 intra-host evolutionary rate was estimated based on HIV-1 RNA sequences from ...plasma samples of blood donors in Japan. Blood donors were assumed to have received no treatment for and have no symptoms of HIV-1 infection because they were healthy, and declared no risky behaviors of HIV-1 infection on a self-reported questionnaire or interview followed by donation. HIV-1 RNA was obtained from 85 plasma samples from 36 blood donors who donated blood multiple times and were HIV-1-positive. The C2V3C3 region which encodes for a part of the envelope protein, and the V3 loop in the C2V3C3 region were analyzed by RT-PCR and direct sequencing, and the sequences were compared. The nucleotide substitution rate was calculated by linear regression. All HIV-1 samples analyzed were classified as subtype B. The mean nucleotide substitution rate in C2V3C3 was calculated to be 6.2 × 10
−3
–1.8 × 10
−2
/site/year (V3: 4.5 × 10
−3
–2.3 × 10
−2
/site/year). The mean non-synonymous substitution rate in C2V3C3 was calculated to be 5.2 × 10
−3
–1.7 × 10
−2
/site/year (V3: 4.5 × 10
−3
–2.1 × 10
−2
/site/year). The mean synonymous substitution rate in C2V3C3 was calculated to be 1.1 × 10
−4
–2.3 × 10
−3
/site/year (V3: 2.9 × 10
−3
/site/year). Among HIV-1 subtype B RNA-positive blood donors in Japan, the nucleotide substitution rate in C2V3C3 was estimated to be higher than that of reported cases using HIV-1 samples mainly obtained from AIDS patients. Compared to AIDS patients, immune responses against HIV-1 are probably more effective in HIV-1 RNA-positive blood donors. Consequently, immune pressure presumably promotes mutation of the virus genome.
BACKGROUND
Antibody screening in pretransfusion tests is necessary to avoid critical complications of blood transfusion. Although red blood cells (RBCs) expressing relevant alloantigen(s) have been ...used for serologic antibody screening, little attention has been given to the use of cell lines, in which blood group antigen gene(s) are transduced, as reagent RBCs for antibody screening.
STUDY DESIGN AND METHODS
The use of an erythroid progenitor cell line for serologic tests was studied. The expression of blood group antigens of erythroid progenitor cells was analyzed by genotyping and flow cytometry. Serologic analysis including hemagglutination was performed using erythroid progenitor cells to evaluate their sensitivity for antibody detection. Overexpression of exogenous erythroid antigen by lentiviral transduction was carried out and investigated for antibody detection sensitivity.
RESULTS
Erythroid progenitor cells contained a substantial amount of hemoglobin and expressed sufficient levels of blood group antigens to detect corresponding monoclonal antibodies. Furthermore, the cell line could acquire an exogenous RBC antigen after lentiviral transduction and detected corresponding monoclonal and alloantibodies with equal sensitivity to antigen‐positive RBCs.
CONCLUSION
Application of erythroid progenitor cell lines for screening for unexpected antibodies could be helpful in solving issues such as reagent availability associated with the conventional RBC‐based assay. The genetic expandability of erythroid progenitor cell lines by gene modification techniques could lead to the development of more convenient reagent RBCs.
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