A prospective observational study of community-acquired bacterial bloodstream infections in Metro Manila, the Philippines.

Community-acquired bacterial bloodstream infections are caused by diverse pathogens with changing antimicrobial-resistance patterns. In low-middle income countries in Southeast Asia, where dengue fever is endemic and a leading cause of fever, limited information is available about bacterial bloodstream infections due to challenges of implementing a blood culture service. This study describes bacterial bloodstream pathogens and antimicrobial-resistance patterns in Metro Manila, the Philippines. We aimed to identify the proportion of patients with a positive blood culture, the bacteria isolated and their antimicrobial resistance patterns, and the clinical characteristics of these patients, in this dengue endemic area. We conducted a prospective observational study in a single hospital enrolling febrile patients clinically suspected of having a community-acquired bacterial bloodstream infection between 1st July 2015 and 30th June 2019. Each patient had a blood culture and additional diagnostic tests according to their clinical presentation. We enrolled 1315 patients and a significant positive blood culture was found in 77 (5.9%) including Staphylococcus aureus (n = 20), Salmonella enterica Typhi (n = 18), Escherichia coli (n = 16), Streptococcus pneumoniae (n = 3) and Burkholderia pseudomallei (n = 2). Thirty-four patients had meningococcal disease diagnosed by culture (n = 8) or blood PCR (n = 26). Additional confirmed diagnoses included leptospirosis (n = 177), dengue virus infection (n = 159) and respiratory diphtheria (n = 50). There were 79 (6.0%, 95%CI 4.8%-7.4%) patients who died within 28 days of enrollment. Patients with a positive blood culture were significantly more likely to die than patients with negative culture (15.2% vs 4.4%, P<0.01). Among S. aureus isolates, 11/20 (55%) were methicillin-resistant (MRSA) and ST30: USA1100 was dominant sequence type (88.9%). Antimicrobial-susceptibility was well preserved in S. enterica Typhi. Among hospitalized patients with clinically suspected community-acquired bacterial bloodstream infection in Metro Manila, the Philippines, 5.9% had a blood culture confirmed infection of whom 15.6% died. S. aureus, including a significant number of MRSA (USA1100 clones), S. enterica Typhi, E.coli and Neisseria meningitidis were frequently identified pathogens.

High prevalence of multiple serotypes of pneumococci in patients with pneumonia and their associated risk factors.

BACKGROUND: Multiple serotypes of pneumococci have epidemiological and clinical implications, such as the emergence of non-vaccine serotypes and the acquisition of antimicrobial resistance. Prevalence of multiple serotypes of pneumococci in adults and their risk factors are not known. METHODS: We enrolled adult patients from age ≥15 years with radiologically confirmed pneumonia in four hospitals across Japan. Pneumococcal pneumonia was defined with a pneumococcal bacterial density of ≥104/mL in sputum by lytA quantitative PCR, and serotypes were determined. Pneumonias with a single serotype were categorised as single-serotype pneumococcal pneumonia and with two or more serotypes as multiple-serotype pneumococcal pneumonia. Multivariable logistic regression was used to assess the risk factors. RESULTS: 3470 patients (median age 77 years, IQR 65-85) were enrolled. Pneumococcal pneumonia was identified in 476 (18.3%, n=2605) patients. Multiple serotypes were detected in 42% of them. Risk of having multiple serotypes was low among patients who had received 23-valent pneumococcal polysaccharide vaccine (PPSV23) vaccines (adjusted OR 0.51 (95% CI 0.27 to 0.94)). Proportion of non-PCV7 PPSV23 serotypes in overall distribution of multiple serotypes was 67.4% (n=324/481) compared with 46.4% (n=128/276) in that of single serotypes (p=0.001). Serotypes 5, 9N/9L, 10A, 12/22/46, 17F and 35F were associated with multiple-serotype pneumonia, and serotypes 6A/6B, 23F, 11 and 6C/6D were associated with single-serotype pneumonia. Proportion of more invasive serotypes (serotypes 1, 5, 7F, 8) was significantly higher in multiple-serotype pneumonia (p=0.001). CONCLUSIONS: Multiple serotypes of pneumococci are common in sputum of adult patients with pneumonia. The risk of multiple-serotype pneumococcal pneumonia is lower than that of single-serotype pneumococcal pneumonia among PPSV23-vaccinated patients. TRIAL REGISTRATION NUMBER: UMIN000006909.

Asymmetric Pericentrosomal CD133 Endosomes Induce the Unequal Autophagic Activity During Cytokinesis in CD133-Positive Human Neuroblastoma Cells.

CD133 is a transmembrane protein that mainly localizes to the plasma membrane in hematopoietic/neural stem cells and cancer stem cells. Although CD133 also localizes to the cytoplasm and is degraded through autophagy, the precise mechanisms responsible for the autophagic degradation of endosomal CD133 currently remain unknown. We demonstrated that endosomal CD133 has unique properties for cell homeostasis. Endosomal CD133 is degraded through p62/SQSTM1-mediated selective autophagy. However, in low basal autophagic cells, such as SK-N-DZ and SH-SY5Y cells, endosomal CD133 accumulates at the pericentrosomal region and conversely suppresses autophagy. Endosomal CD133 also asymmetrically distributes to the pericentrosomal region and induces unequal autophagic activity between 2 daughter cells during cytokinesis in SK-N-DZ and TGW cells. In addition, the asymmetric distribution of pericentrosomal CD133 endosomes and nuclear ß-catenin cooperatively suppresses autophagic activity against p62 in SK-N-DZ cells. Thus, the present study suggests that the asymmetric distribution of pericentrosomal CD133 endosomes induces the symmetry breaking of autophagic activity during cytokinesis in cooperation with nuclear ß-catenin.

rs9459874 and rs1012656 in CCR6/FGFR1OP confer susceptibility to primary biliary cholangitis.

Primary biliary cholangitis (PBC) is a chronic cholestatic autoimmune liver disease that appears to be strongly influenced by genetic factors. Recently, an international meta-analysis of genome-wide association studies (GWAS) identified CC-Motif Chemokine Receptor-6 (CCR6) and FGFR1 Oncogene-Partner (FGFR1OP) as PBC-susceptibility genes. However, the lead single nucleotide polymorphisms (SNPs) of CCR6/FGFR1OP showed low linkage disequilibrium with each other in East Asian and European populations. Additionally, the primary functional variants and the molecular mechanisms responsible for PBC-susceptibility remain unclear. Here, among the PBC-susceptibility SNPs identified by high-density association mapping in our previous meta-GWAS (Patients: n = 10,516; healthy controls: n = 20,772) within the CCR6/FGFR1OP locus, rs9459874 and rs1012656 were identified as primary functional variants. These functional variants accounted for the effects of GWAS-identified lead SNPs in CCR6/FGFR1OP. Additionally, the roles of rs9459874 and rs1012656 in regulating FGFR1OP transcription and CCR6 translation, respectively, were supported by expression quantitative trait loci (eQTL) analysis and gene editing technology using the CRISPR/Cas9 system. Immunohistochemistry showed higher expression of CCR6 protein in the livers of patients with PBC than in those of a non-diseased control. In conclusion, we identified primary functional variants in CCR6/FGFR1OP and revealed the molecular mechanisms by which these variants confer PBC-susceptibility in an eQTL-dependent or -independent manner. The approach in this study is applicable for the elucidation of the pathogenesis of other autoimmune disorders in which CCR6/FGFR1OP is known as a susceptibility locus, as well as PBC.

Unique characteristics of new complete blood count parameters, the Immature Platelet Fraction and the Immature Platelet Fraction Count, in dengue patients.

The advanced platelet parameters Immature Platelet Fraction and Immature Platelet Fraction Count have been implemented in clinical practice as measures of thrombopoietic activity, mainly in hematologic disorders that cause thrombocytopenia. The purpose of this observational study was to examine thrombopoiesis as reflected by these 2 new CBC parameters in patients infected with dengue. The study was conducted in infectious disease referral hospital in Metro Manila, the Philippines. We enrolled hospitalized patients at admission who were diagnosed with acute dengue or community acquired bacterial infection (CABI). Immature Platelet Fraction (IPF) and Immature Platelet Fraction Count were evaluated at admission and during hospitalization. A total of 606 patients were enrolled from May 1, 2017 to June 1, 2018. The participants consisted of 152 patients with dengue infection, 180 confirmed CABI, and 274 suspected CABI patients. At admission, the percent IPF (IPF%) of the patients with dengue was significantly higher than that of the confirmed CABI patients (median 3.7% versus 1.9%; p <0.001). In a time course evaluation, there was no significant difference of IPF% between the patients with dengue infection and the confirmed CABI patients in the febrile phase (median 1.9% versus 2.4%; p = 0.488), however, the IPF% of the patients with dengue infection increased to be significantly higher than that of the confirmed CABI patients in the critical phase (median 5.2% versus 2.2%; p <0.001). Our study elucidated the unique characteristics and time-course trends of IPF percent and number (IPF#) in the patients with dengue infection. IPF% and IPF# are potentially valuable parameters in dengue and further investigation is required for the optimal use in clinical practice.

Hepatitis B virus infection among pregnant mothers and children after the introduction of the universal vaccination program in Central Vietnam.

A birth cohort study was conducted in Khan Hoa Province, central Vietnam between 2009 and 2012 to determine the seroprevalence of hepatitis B virus (HBV) in pregnant women and their children, and associated risk factors. We enrolled 1987 pregnant women with their babies at the birth phase, and 12.6% (95% confidence interval [CI]: 11.1-14.0) of mothers were hepatitis B surface antigen (HBsAg)+. At 2-year follow-up phase, 1339 (67.4%) children were enrolled of whom 76.6% completed hepatitis B vaccines (HepB) and 1.9% (95% CI: 1.2-2.7) were HBsAg+. When mothers were hepatitis B e antigen (HBeAg)+, 28.3% of children have got infected even with complete HepB. HBV infection in mothers, hepatitis B surface antibody (anti-HBs antibody) below the seroprotective level in children, and mothers with pre-pregnancy low body mass index were associated with HBV infection in children. Meanwhile, HBV infection in children, older maternal age, no or incomplete doses of HepB, and boys were associated with anti-HBs antibody below the seroprotective level in children. Our birth cohort study determined a low rate of congenital HBV infection and associated risk factors in Vietnam, however further studies are needed to advance prevention including anti-viral therapy in pregnant women at high risk.

[Evaluation of Accuracy and Availability of the Antimicrobial Resistance Testing by the Direct Disc Methods Using AmpC/ESBL Differential Discs in the Samples in Which Enterobacterales are Detected in Blood Culture].

The emergence and dissemination of drug-resistant Gram-negative bacilli have been recognized as a serious health concern in worldwide. The isolation rates of Extended-Spectrum ß-lactamases (ESBL) and AmpC ß-lactamases (AmpC) producing gram negative rods are increasing in our hospital. In the present study, we evaluate the availability of the antimicrobial resistance testing by the direct disc methods using AmpC/ESBL differential discs. One hundred and ten strains of Enterobacterales were isolated during the observation period, of which 19 strains (17%) were ESBL-positive and 6 strains (5%) were AmpC-positive. The positive and negative coincidence rate between direct disc methods and standard disc methods were 100%. We conclude that the direct disc method is a useful and rapid detection method for ESBL and AmpC from blood culture samples.

Deficiency of mannose-binding lectin is a risk of Pneumocystis jirovecii pneumonia in a natural history cohort of people living with HIV/AIDS in Northern Thailand.

BACKGROUND: Mannose-binding lectin (MBL) plays a pivotal role in innate immunity; however, its impact on susceptibility to opportunistic infections (OIs) has not yet been examined in a natural history cohort of people living with HIV/AIDS. METHODS: We used archived samples to analyze the association between MBL expression types and risk of major OIs including Pneumocystis jirovecii pneumonia (PCP), cryptococcosis, talaromycosis, toxoplasmosis, and tuberculosis in a prospective cohort in Northern Thailand conducted from 1 July 2000 to 15 October 2002 before the national antiretroviral treatment programme was launched. RESULTS: Of 632 patients, PCP was diagnosed in 96 (15.2%) patients, including 45 patients with new episodes during the follow-up period (1006.5 person-years). The total history of PCP was significantly associated with low MBL expression type: high/intermediate (81/587, 13.8%), low (10/33, 30.3%) and deficient (5/12, 41.7%) (p = 0.001), whereas the history of other OIs showed no relation with any MBL expression type. Kaplan-Meier analysis (n = 569; log-rank p = 0.011) and Cox's proportional hazards model revealed that deficient genotype dramatically increased the risk of PCP, which is independent upon sex, age, CD4 count, HIV-1 viral load and hepatitis B and C status (adjusted hazard ratio 7.93, 95% confidence interval 2.19-28.67, p = 0.002). CONCLUSIONS: Deficiency of MBL expression is a strong risk factor determining the incidence of PCP but not other major OIs.

Correction to: Changes in nutritional status of children who lived in temporary shelters in Bhaktapur municipality after the 2015 Nepal earthquake.

[This corrects the article DOI: 10.1186/s41182-020-00225-8.].

The novel early predictive marker presepsin for postoperative pancreatic fistula: A pilot study.

Postoperative pancreatic fistula (PF) is a major and serious complication that occurs after pancreaticoduodenectomy (PD). The aim of the current study was to evaluate the use of a novel biomarker, presepsin, for predicting clinically relevant postoperative pancreatic fistula (CR-POPF) after PD. A prospective pilot study was conducted using 30 consecutive patients who underwent PD. Risk factors and candidates for predictive biomarkers for CR-POPF were statistically analyzed. CR-POPF (grade B and C; determined according to the guidelines of the International Study Group of Pancreatic Fistula) occurred in 15 patients (50%). Univariate analysis revealed that certain underlying conditions, including non-pancreatic cancer, smaller pancreatic ducts and soft pancreas texture were significantly associated with CR-POPF (P=0.005, P=0.004 and P=0.014, respectively). Furthermore, on day 1 post surgery (POD1), white blood cell count (P=0.040), levels of serum amylase (P=0.002) and serum presepsin (P=0.012), and the concentration of presepsin in drainage fluid (P<0.001) were significantly increased in CR-POPF compared with non-CR-POPF cases. Receiver operating characteristic curve analyses revealed that, on POD1, serum amylase and the concentration of presepsin in drainage fluid had an area under the curve value exceeding 0.8. A multivariate logistic regression analysis revealed that a higher concentration of presepsin in the drainage fluid was an independent predictive marker for CR-POPF (odds ratio, 14.503; 95% confidence interval, 1.750-120.229; P=0.013). To the best of our knowledge, the present study demonstrated for the first time that presepsin concentration in drainage fluid is a useful marker of CR-POPF after PD.

Changes in nutritional status of children who lived in temporary shelters in Bhaktapur municipality after the 2015 Nepal earthquake.

BACKGROUND: The nutritional status of children may deteriorate after natural disasters such as earthquakes. A 7.8 Richter scale earthquake struck Nepal in 2015 that affected 1.1 million children. Children whose homes were destroyed and had to live in temporary shelters were at risk of malnutrition. With the support of Nagasaki University School of Tropical Medicine and Global Health (TMGH) and Siddhi Memorial Hospital (SMH), we conducted a nutritional survey of under-5 children living in temporary shelters in Bhaktapur Municipality in 2015 immediately after the earthquake and a follow-up survey in 2017. RESULTS: We found 591 under-5 children living in 22 temporary shelters in 2015. A total of 285 children were followed up and re-assessed in 2017. In a paired analysis (n = 285), the prevalence of underweight children increased from 10.9% in 2015 to 14.0% in 2017 (P < 0.001), stunting increased from 26.7 to 31.9% (P = 0.07), and wasting decreased from 4.2 to 2.5% (P = 0.19). CONCLUSIONS: Children who lived in temporary shelters after the 2015 Nepal earthquake might be at increased risk of a deterioration in nutritional status.

Author Correction: Exposure to paternal tobacco smoking increased child hospitalization for lower respiratory infections but not for other diseases in Vietnam.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Challenges in diagnosing scrub typhus among hospitalized patients with undifferentiated fever at a national tertiary hospital in northern Vietnam.

BACKGROUND: Scrub typhus (ST) is a leading cause of non-malarial febrile illness in Southeast Asia, but evidence of its true disease burden is limited because of difficulties of making the clinical diagnosis and lack of adequate diagnostic tests. To describe the epidemiology and clinical characteristics of ST, we conducted an observational study using multiple diagnostic assays at a national tertiary hospital in Hanoi, Vietnam. METHODOLOGY/PRINCIPAL FINDINGS: We enrolled 1,127 patients hospitalized with documented fever between June 2012 and May 2013. Overall, 33 (2.9%) patients were diagnosed with ST by PCR and/or screening of ELISA for immunoglobulin M (IgM) with confirmatory tests: 14 (42.4%) were confirmed by indirect immunoperoxidase assay (IIP), and 19 (57.6%) were by IIP and PCR. Living by farming, conjunctival injection, eschar, aspartate aminotransferase elevation, and alanine aminotransferase elevation were significantly associated with ST cases (adjusted odds ratios (aORs): 2.8, 3.07, 48.8, 3.51, and 4.13, respectively), and having a comorbidity and neutrophilia were significantly less common in ST cases (aORs: 0.29 and 0.27, respectively). The majority of the ST cases were not clinically diagnosed with rickettsiosis (72.7%). Dominant IIP reactions against a single antigen were identified in 15 ST cases, whereas indistinguishably high reactions against multiple antigens were seen in 11 ST cases. The most frequently observed dominant IIP reaction was against Karp antigen (eight cases) followed by Gilliam (four cases). The highest diagnostic accuracy of IgM ELISA in acute samples was 78%. In a phylogenetic analysis of the 56-kDa type-specific antigen gene, the majority (14 cases) were located in the Karp-related branch followed by the Gilliam-related (two cases), Kato-related (two cases), and TA763-related clades (one case). CONCLUSIONS/SIGNIFICANCE: Both the clinical and laboratory diagnoses of ST remain challenging at a tertiary hospital. Implementation of both serological and nucleic acid amplification assays covering endemic O. tsutsugamushi strains is essential.

Asthma, Rhinoconjunctivitis, Eczema, and the Association with Perinatal Anthropometric Factors in Vietnamese Children.

Few studies have investigated possible causative and protective factors associated with allergic diseases in resource-limited countries, Southeast Asia. We estimated the current prevalence of asthma, rhinoconjunctivitis, and eczema among 6-year-old children, and identified anthropometric factors associated with asthma, rhinoconjunctivitis and eczema, in South-Central Vietnam. A birth cohort study recruited 1,999 children born at a provincial hospital in Nha Trang, Vietnam between May 2009 and May 2010. A 6-year follow-up survey was conducted where clinical, familial, and environmental information was collected by interviewing caregivers using a standardized form based on the International Study of Asthma and Allergies in Childhood, Phase Three Core and Environmental Questionnaire for 6-7-year-old children. The odds ratios of asthma, rhinoconjunctivitis, and eczema for anthropometric factors were estimated using logistic regression analysis. In total, 1202 children participated in the follow-up survey. The proportions of children who had current asthma, rhinoconjunctivitis, and eczema were 5.1% (95% confidence interval [CI] 3.9-6.5%), 11.5% (9.7-13.4%), and 6.7% (5.3-8.2%), respectively. Low birthweight (adjusted odds ratio 5.12, 95% CI 1.92-13.64) was independently associated with increased risk of eczema. Further studies are necessary to understand the involved mechanism.

Recycling endosomal CD133 functions as an inhibitor of autophagy at the pericentrosomal region.

CD133 is a transmembranous protein that mainly localises to the plasma membrane in haematopoietic and neural stem cells as well as cancer stem cells. Although CD133 also localises to the cytoplasm, the mechanism of action and function of cytoplasmic CD133 currently remain unknown. We herein demonstrated that when Src family kinase activity is weak, CD133 interacts with HDAC6 and is transported to the pericentrosomal region after internalization and endosome formation via the dynein-based traffic system. Pericentrosomal CD133 is then recycled to the plasma membrane via recycling endosomes. At the pericentrosomal region, endosomal CD133 captures GABARAP, an initiator of autophagy, and inhibits GABARAP-mediated ULK1 activation and the subsequent initiation of autophagy. Furthermore, pericentrosomal CD133 suppresses cell differentiation, such as primary cilium formation and neurite outgrowth, by inhibiting autophagy. Thus, the present results provide evidence to suggest that pericentrosomal CD133 has the unique property of maintaining the undifferentiated status of cells by inhibiting autophagy.

Impact of HLA Allele-KIR Pairs on Disease Outcome in HIV-Infected Thai Population.

BACKGROUND: Class I human leukocyte antigen (HLA) molecules contribute to HIV control through antigen presentation to both cytotoxic T lymphocytes and natural killer cells. Contribution of cytotoxic T lymphocytes to HIV clinical outcome by HLA alleles has been well studied. However, reports about the role of natural killer cells in HIV clinical outcome, particularly, about the effect of HLA-killer immunoglobulin-like receptor (KIR) pairs, remain incomplete. METHODS: The effects of HLA allele-KIR pairs on HIV clinical outcome were statistically analyzed in a Thai cohort of treatment-naive chronically infected population (n = 209). RESULTS: Five HLA allele-KIR pairs scored significantly in viral load (VL) differences. Among them, opposing effects on VL were identified among subjects expressing KIR2DL2 ligands within the HLA-C1 group: higher VL in individuals expressing HLA-B*46:01+KIR2DL2+ compared with individuals without KIR (HLA-B*46:01+KIR2DL2-) (5.0 vs 4.6 log10 copies/mL, P = 0.02), in HLA-C*01:02+KIR2DL2+ (5.0 vs 4.6 log10 copies/mL; P = 0.02), and lower VL in HLA-C*12:03+KIR2DL2+ (4.3 vs 5.6 log10 copies/mL; P = 0.01). In the longitudinal analysis of a ten-year follow-up, HLA-B*46:01+KIR2DL2+ve subjects also had a higher mortality rate compared with the subjects without that pair, independent of variables including antiretroviral treatment, as well as CD4 T-cell count, sex, and age (adjusted hazard ratio 5.9, P = 0.02). CONCLUSION: We identified several HLA allele-KIR pairs associated with clinical outcome differences including opposing effects on VL within 1 HLA group with the same KIR. Among them, HLA-B*46:01 emerged in Southeast Asia about 50,000 years ago and is now the most prevalent HLA-B allele in that area. These findings highlight that each endemic area has unique features of anti-HIV innate immunity that impact clinical outcome.

Accuracy of High-Throughput Nanofluidic PCR-Based Pneumococcal Serotyping and Quantification Assays Using Sputum Samples for Diagnosing Vaccine Serotype Pneumococcal Pneumonia: Analyses by Composite Diagnostic Standards and Bayesian Latent Class Models.

The lack of reliable diagnostic tests for detecting vaccine serotype pneumococcal pneumonia (VTPP) remains a challenging issue in pneumococcal vaccine studies. This study assessed the performances of high-throughput nanofluidic PCR-based pneumococcal serotyping and quantification assay methods using sputum samples (the nanofluidic sputum quantitative PCR [Sp-qPCR] assay) to diagnose 13-valent pneumococcal conjugate VTPP compared with the performance of the serotype-specific urinary antigen detection (UAD) assay using urine samples. Adult pneumonia patients from Japan were enrolled in this study between September 2012 and August 2014. Sputum samples were subjected to the nanofluidic Sp-qPCR assay, quantitatively cultured, and serotyped by the Quellung reaction (SpQt). Urine samples were tested by the UAD method. The diagnostic performances of these tests were assessed using composite reference standards and Bayesian latent class models (BLCMs). Among 244 total patients, 27 (11.1%) tested positive with the UAD assay, while 16 (6.6%) and 34 (13.9%) tested positive with the SpQt and nanofluidic Sp-qPCR assays, respectively, with a cutoff value of ≥104 DNA copies/ml, which showed the maximum value of the Youden index. Using BLCMs, the estimated prevalence for VTPP was 12.9%, and the nanofluidic Sp-qPCR assay demonstrated the best performance (sensitivity, 90.2%; specificity, 96.9%), followed by UAD (sensitivity, 75.6%; specificity, 97.9%) and SpQt (sensitivity, 45.8%; specificity, 99.5%). However, when a higher cutoff value of ≥107 DNA copies/ml was applied, the performance of UAD became comparable to that of Sp-qPCR. The vaccine serotype-specific pneumococcal DNA load in sputum among UAD-positive patients was 3 logs higher than that among UAD-negative patients (P = 0.036). The nanofluidic Sp-qPCR assay may be accurate and useful for detecting VTPP among adults.

HLA-DRB1 and DQB1 alleles in Japanese type 1 autoimmune hepatitis: The predisposing role of the DR4/DR8 heterozygous genotype.

OBJECTIVE: Autoimmune hepatitis (AIH) is a chronic progressive liver disease. AIH is composed predominantly of type 1 in Japanese populations. The genetic and environmental factors are associated with the pathogenesis of AIH. HLA-DRB1*03:01 and *04:01 are associated with type 1 AIH in European and *04:05 in Japanese populations. Here, we conducted an HLA association study in order to find HLA alleles or haplotypes predisposing or protective for Japanese AIH. METHODS: HLA-DRB1 and DQB1 genotyping of 360 type 1 AIH patients and 1026 healthy controls was performed. RESULTS: The predisposing association of DRB1*04:01 (P = 0.0006, corrected P [Pc] = 0.0193, odds ratio [OR] 2.97, 95% confidence interval [CI] 1.62-5.43), DRB1*04:05 (P = 1.89×10-21, Pc = 5.86×10-20, OR 3.41, 95% CI 2.65-4.38), and DQB1*04:01 (P = 4.66×10-18, Pc = 6.99×10-17, OR 3.89, 95% CI 2.84-5.33) and the protective association of DRB1*13:02 (P = 0.0003, Pc = 0.0080, OR 0.48, 95% CI 0.32-0.72) with Japanese type 1 AIH were observed. An association of the DR4/DR8 heterozygous genotype with Japanese AIH was identified for the first time (P = 3.12×10-9, OR 3.52, 95% CI 2.34-5.29). Susceptible diplotypes were DRB1*04:05-DQB1*04:01/DRB1*08:02-DQB1*03:02 (P = 0.0004, OR 24.77, 95% CI 1.45-424.31) and DRB1*04:05-DQB1*04:01/DRB1*08:03-DQB1*06:01 (P = 1.18×10-6, OR 10.64, 95% CI 3.19-35.46). Serum levels of Immunoglobulin G and Immunoglobulin M, International Autoimmune Hepatitis Group score, positive rate of anti-smooth muscle antibodies, and the rate of definite AIH were higher in AIH patients with DRB1*04:05 than without. CONCLUSIONS: The important roles of specific combinations of DRB1 and DQB1 alleles or haplotypes in the pathogenesis of type 1 AIH were suggested. The association of DR4/DR8 heterozygous genotype suggested the pathologic importance of trans-complementing DQα-ß heterodimer molecules encoded by DQA1 allele of one haplotype and the DQB1 allele of the other haplotype, as it was proposed in the HLA association studies of Type 1 diabetes.

Principal contribution of HLA-DQ alleles, DQB1*06:04 and DQB1*03:01, to disease resistance against primary biliary cholangitis in a Japanese population.

Identification of the primary allele(s) in HLA class II associated diseases remains challenging because of a tight linkage between alleles of HLA-DR and -DQ loci. In the present study, we determined the genotypes of seven HLA loci (HLA-A, -B, -DRB1, -DQA1, -DQB1, -DPA1 and -DPB1) for 1200 Japanese patients with primary biliary cholangitis and 1196 controls. Observation of recombination derivatives facilitated an evaluation of the effects of individual HLA alleles consisting of disease-prone/disease-resistant HLA haplotypes. Consequently, a primary contribution of DQB1*06:04 (odds ratio: 0.19, p = 1.91 × 10-22), DQB1*03:01 (odds ratio: 0.50, p = 6.76 × 10-10), DRB1*08:03 (odds ratio: 1.75, p = 1.01 × 10-7) and DQB1*04:01 (odds ratio: 1.50, p = 9.20 × 10-6) was suggested. Epistasis of the protective DQB1*06:04 to risk conferred by DRB1*08:03 was demonstrated by subpopulation analysis, implicating the presence of an active immunological mechanism that alleviates pathogenic autoimmune reactions. Further, the contribution of the aforementioned HLA alleles as well as an HLA-DP allele, DPB1*02:01 to the association signals of 304 loci among 4103 SNPs in the HLA region at the genome-wide level of significance (p values less than 5 × 10-8) was demonstrated by the stepwise exclusion of the individuals possessing these HLA alleles from the comparison.

Effects of HLA-DRB1 alleles on susceptibility and clinical manifestations in Japanese patients with adult onset Still's disease.

BACKGROUND: HLA-DRB1 alleles are major determinants of genetic predisposition to rheumatic diseases. We assessed whether DRB1 alleles are associated with susceptibility to particular clinical features of adult onset Still's disease (AOSD) in a Japanese population by determining the DRB1 allele distributions. METHODS: DRB1 genotyping of 96 patients with AOSD and 1,026 healthy controls was performed. Genomic DNA samples from the AOSD patients were also genotyped for MEFV exons 1, 2, 3, and 10 by direct sequencing. RESULTS: In Japanese patients with AOSD, we observed a predisposing association of DRB1*15:01 (p = 8.60 × 10-6, corrected p (Pc) = 0.0002, odds ratio (OR) = 3.04, 95% confidence interval (95% CI) = 1.91-4.84) and DR5 serological group (p = 0.0006, OR = 2.39, 95% CI = 1.49-3.83) and a protective association of DRB1*09:01 (p = 0.0004, Pc = 0.0110, OR = 0.34, 95% CI = 0.18-0.66) with AOSD, and amino acid residues 86 and 98 of the DRß chain were protectively associated with AOSD. MEFV variants were identified in 49 patients with AOSD (56.3%). The predisposing effect of DR5 was confirmed only in patients with AOSD who had MEFV variants and not in those without MEFV variants. Additionally, DR5 in patients with AOSD are associated with macrophage activation syndrome (MAS) and steroid pulse therapy. CONCLUSION: The DRB1*15:01 and DR5 are both associated with AOSD susceptibility in Japanese subjects. A protective association between the DRB1*09:01 allele and AOSD was also observed in these patients. Our data also highlight the effects of DRB1 alleles in susceptibility to AOSD.