Dengue virus transmission risk in blood donation: Evidence from Thailand.

Individuals infected with dengue virus (DENV) often show no symptoms, which raises the risk of DENV transfusion transmission (TT-DENV) in areas where the virus is prevalent. This study aimed to determine the evidence of DENV infection in blood donors from different geographic regions of Thailand. A cross-sectional study was conducted on blood donor samples collected from the Thai Red Cross National Blood Center and four regional blood centers between March and September 2020. Screening for DENV nonstructural protein 1 (NS1), anti-DENV immunoglobulin G (IgG), and IgM antibodies was performed on residual blood from 1053 donors using enzyme-linked immunosorbent assay kits. Positive NS1 and IgM samples indicating acute infection were verified using four different techniques, including quantitative real-time (q) RT-PCR, nested PCR, virus isolation in C6/36 cells, and mosquito amplification. DENV IgG seropositivity was identified in 89% (938/1053) of blood donors. Additionally, 0.4% (4/1053) and 2.1% (22/1053) of Thai blood donors tested positive for NS1 and IgM, respectively. The presence of asymptomatic dengue virus infection in healthy blood donors suggests a potential risk of transmission through blood transfusion, posing a concern for blood safety.

Long-term kidney outcomes after leptospirosis: a prospective multicentre cohort study in Thailand.

BACKGROUND: Leptospirosis is one of the most important public-health zoonotic diseases in the tropics that can cause severe organ dysfunction and death. Currently there are insufficient data on long-term renal dysfunction in patients after leptospirosis infection. METHODS: A prospective multicentre cohort study was conducted at 15 hospitals in the Sisaket province of Thailand. Confirmed leptospirosis patients admitted from 1 December 2015 to 30 November 2018 were followed between 1 February 2020 and 31 October 2020 (median 4.1 years after hospital discharge). The primary outcome was a composite of major kidney adverse events (MAKEs) including all-cause mortality, dialysis and new-onset chronic kidney disease (CKD). RESULTS: Of the 217 confirmed leptospirosis cases enrolled, 32.7% were classified as having severe leptospirosis. Fifteen cases (6.9%) were deceased at the time of hospital admission. After a median follow-up time of 4.18 years, 30 patients had died and 33 patients developed CKD. Patients with severe leptospirosis had a significantly higher risk of MAKEs {adjusted hazard ratio 2.45 [95% confidence interval (CI) 1.44-4.18]}. Patients with intensive care unit admission, pulmonary haemorrhage and acute kidney injury also had a higher risk of MAKEs and all-cause mortality. Participants with severe leptospirosis in the follow-up cohort showed a higher risk of developing CKD compared with non-severe leptospirosis [adjusted odds ratio 3.22 (95% CI 1.04-9.96)], especially renal magnesium and phosphate wasting. CONCLUSION: Leptospirosis patients, especially severe leptospirosis, are associated with long-term kidney sequelae. Our finding reflects the importance of long-term follow-up and the urgent need for specific interventions.

Modulation of hepatitis B virus pregenomic RNA stability and splicing by histone deacetylase 5 enhances viral biosynthesis.

Hepatitis B virus (HBV) is a worldwide health problem without curative treatments. Investigation of the regulation of HBV biosynthesis by class I and II histone deacetylases (HDACs) demonstrated that catalytically active HDAC5 upregulates HBV biosynthesis. HDAC5 expression increased both the stability and splicing of the HBV 3.5 kb RNA without altering the translational efficiency of the viral pregenomic or spliced 2.2 kb RNAs. Together, these observations point to a broader role of HDAC5 in regulating RNA splicing and transcript stability while specifically identifying a potentially novel approach toward antiviral HBV therapeutic development.

Genetic variation in STAT4 is associated with treatment response to pegylated interferon in patients with chronic hepatitis B.

BACKGROUND: Signaling pathways in the STAT4 gene play an essential role in interferon-mediated antiviral effects. OBJECTIVE: This study was aimed at investigating the role of rs7574865, a single nucleotide polymorphism (SNP) in STAT4, in patients with chronic hepatitis B (CHB) treated with pegylated interferon (PEG-IFN). METHODS: A total 261 Thai patients (115 HBeAg-positive and 146 HBeAg-negative CHB) treated with 48-week PEG-IFN were recruited. Virological response (VR) at 48 weeks post treatment was defined as HBeAg seroconversion plus HBV DNA < 2,000 IU/mL for HBeAg-positive CHB and HBV DNA < 2,000 IU/mL for HBeAg-negative CHB. The SNP was analyzed by TaqMan PCR assay. RESULTS: The distribution of GG, GT and TT genotypes of rs7574865 was 41.8%, 42.9% and 15.3%, respectively. There was no different in its distribution according to HBeAg status. Overall, patients with TT genotype, compared with non-TT genotype, achieved higher VR (64.3% vs. 30.5%; P < 0.001) and HBsAg clearance (23.8% vs. 5.0%; P < 0.001). There was the same trend in the HBeAg-positive group (VR, 52.4% vs. 30.9%; P = 0.077; HBsAg clearance, 23.8% vs. 6.4%; P = 0.028) and in the HBeAg-negative group (VR, 68.4% vs. 32.3%; P = 0.004; HBsAg clearance, 21.1% vs. 4.7%; P = 0.026). Multiple regression analysis demonstrated that low baseline HBsAg level and TT genotype were factors independently associated with VR and HBsAg clearance. CONCLUSIONS: Our data support that SNP rs7574865 is associated with response to PEG-IFN therapy in Thai patients with CHB, regardless of baseline HBeAg status. Thus, the determination of this SNP could maximize cost-effectiveness of PEGIFN in patients with CHB.

Reverse transcriptase droplet digital PCR vs reverse transcriptase quantitative real-time PCR for serum HBV RNA quantification.

Serum hepatitis B virus (HBV) RNA is a novel marker reflecting the activity of covalently closed circular DNA. However, the methodology for detecting HBV RNA has been a technical challenge. In this study, the performance of reverse transcription droplet digital polymerase chain reaction (RT-ddPCR) for quantifying HBV RNA was compared with that of reverse transcription quantitative real-time PCR (RT-qPCR) in serum samples collected from treatment-naïve patients with different phases of chronic hepatitis B (CHB). A total of 417 serum samples, including 136 HBeAg-positive CHB and 281 HBeAg-negative CHB were examined. HBV RNA levels measured by RT-ddPCR and RT-qPCR showed a high degree of linearity and quantitative correlation. The limit of detections of RT-ddPCR and RT-qPCR assays were 102 and 103 copies/mL, respectively. Our results also demonstrated that RT-ddPCR was superior to RT-qPCR in terms of its consistency for quantifying HBV RNA across all concentrations. In the HBeAg-positive group, serum HBV RNA levels based on RT-ddPCR were moderately correlated with HBV DNA (r = 0.591, P < .001) and HBsAg (r = 0.502, P < .001). Among patients with HBeAg-negative CHB, serum HBV RNA levels were moderately correlated with HBV DNA (r = 0.603, P < .001) but had weak correlation with HBsAg (r = 0.203, P = .001). In summary, RT-ddPCR could enhance the sensitivity of serum HBV RNA detection, particularly among the HBeAg-negative group with low viral loads. Thus, RT-ddPCR could serve as an optimal method for HBV RNA quantification in clinical practice.

Baseline and kinetics of serum hepatitis B virus RNA predict response to pegylated interferon-based therapy in patients with hepatitis B e antigen-negative chronic hepatitis B.

Serum hepatitis B virus (HBV) RNA has emerged as a novel biomarker of treatment response. This study aimed to investigate the role of this marker in predicting long-term outcome of patients with hepatitis B e antigen (HBeAg)-negative chronic hepatitis B (CHB) receiving pegylated interferon (PEG-IFN)-based therapy. Serial serum samples from 91 patients with HBeAg-negative CHB previously treated with PEG-IFN alone or combined with entecavir in a randomized trial were retrospectively analysed. HBV RNA quantification was examined by droplet digital PCR. At the end of 3 years post-treatment follow-up, maintained virological response (MVR, HBV DNA < 2000 IU/mL), and hepatitis B surface antigen (HBsAg) clearance were achieved in 37.4% (34/91) and 7.7% (7/91), respectively. Baseline serum HBV RNA concentrations correlated with HBV DNA and covalently closed circular DNA but did not correlate with HBsAg levels. Multiple regression analysis showed that pre-treatment HBV RNA and HBsAg were independently associated with MVR and HBsAg clearance. Baseline HBV RNA (cut-off 2.0 log10  copies/mL) had a positive predictive value (PPV) and a negative predictive value in predicting MVR of 80.8% and 80.0%, respectively. At the same cut-off value, PPV and NPV for predicting HBsAg clearance were 30.8% and 95.4%, respectively. At week 12 during therapy, HBV RNA level ≥ 2 log10 copies/mL displayed high NPVs of achieving MVR and HBsAg clearance (95% and 100%, respectively). In conclusion, the measurement of HBV RNA prior to PEG-IFN-based therapy could identify patients with high probability of MVR. In addition, HBV RNA kinetics may serve as a promising "stopping rule" in patients infected with HBV genotypes B or C.

Proceedings of the 6th Asia Dengue Summit, June 2023.

The 6th Asia Dengue Summit (ADS) themed "Road Map to Zero Dengue Death" was held in Thailand from 15th-16th June 2023. The summit was hosted by Tropical Medicine Cluster, Chulalongkorn University, Bangkok, Thailand in conjunction with Queen Saovabha Memorial Institute, The Thai Red Cross Society; Faculty of Tropical Medicine, Mahidol University; and the Ministry of Public Health. The 6th ADS was convened by Asia Dengue Voice and Action (ADVA); Global Dengue and Aedes Transmitted Diseases Consortium (GDAC); Southeast Asian Ministers of Education Tropical Medicine and Public Health Network (SEAMEO TROPMED); Fondation Mérieux (FMx) and the International Society for Neglected Tropical Diseases (ISNTD). Dengue experts from academia and research, and representatives from the Ministries of Health, Regional and Global World Health Organization (WHO) and International Vaccine Institute (IVI) participated in the three-day summit. With more than 51 speakers and 451 delegates from over 24 countries, 10 symposiums, and 2 full days, the 6th ADS highlighted the growing threat of dengue and its antigenic evolution, flagged the urgent need to overcome vaccine hesitancy and misinformation crisis, and focused on dengue control policies, newer diagnostics, therapeutics and vaccines, travel-associated dengue, and strategies to improve community involvement.

The combination of RPA-CRISPR/Cas12a and Leptospira IgM RDT enhances the early detection of leptospirosis.

BACKGROUND: Lack of available sensitive point-of-care testing is one of the primary obstacles to the rapid diagnosis of leptospirosis. The purpose of this study was to test the performance of two point-of-care tests, a clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated protein 12a (CRISPR/Cas12a) fluorescence-based diagnostic assay (FBDA), a Leptospira immunoglobulin M (IgM) rapid diagnostic test (RDT), and the two tests combined. METHODOLOGY/PRINCIPAL FINDINGS: For the diagnosis of 171 clinical samples, a recombinase polymerase amplification (RPA)-CRISPR/Cas12a FBDA for whole blood and Leptospira IgM RDT (Medical Science Public Health, Thailand) for serum were used. The confirmed cases were determined by using any positive qPCR, microscopic agglutination test (MAT), and culture results. Diagnostic accuracy was assessed on the first day of enrollment and stratified by the day after symptom onset. The overall sensitivity of the Leptospira IgM RDT and RPA-CRISPR/Cas12a FBDA was 55.66% and 60.38%, respectively. When the two tests were combined, the sensitivity rose to 84.91%. The specificity of each test was 63.08% and 100%, respectively, and 63.08% when combined. The sensitivity of the Leptospira IgM RDT rose on days 4-6 after the onset of fever, while the RPA-CRISPR/Cas12a FBDA continued to decrease. When the two tests were combined, the sensitivity was over 80% at different days post-onset of fever. CONCLUSIONS/SIGNIFICANCE: The combination of Leptospira IgM RDT and RPA-CRISPR/Cas12 FBDA exhibited significant sensitivity for the detection of leptospires at various days after the onset of fever, thereby reducing the likelihood of misdiagnosis. The combination of these assays may be suitable for early leptospirosis screening in situations with limited resources.

Seroprevalence of leptospirosis among blood donors in an endemic area.

Thailand is known to be endemic for leptospirosis. This bacterium may pose a potential risk to transfusion safety. This study was a cross-sectional study examining the seroprevalence of leptospirosis among Thai blood donors. A total of 1053 serum specimens collected from blood donors residing in 5 regions of Thailand during March to September 2020 were included in this study. All samples were tested for the presence of antibodies to 22 leptospiral serovars using the microscopic agglutination test (MAT) and anti-Leptospira IgG antibodies using commercially available enzyme immunoassay. We found no evidence of recent exposure to Leptospira spp. in sera of healthy Thai blood donors by MAT, including those in higher-risk areas. However, in this same group, we did find small numbers of past exposure (1.7%) to Leptospira spp. by IgG ELISA. According to the findings of this study, there is currently no evidence for implementing new blood banking procedures to identify possible carriers in Thailand, however these should be continually monitored and revised according to the infectious disease burden in each country. It should be noted that there was a difference in the occupation rate between the general population reported in Thailand and blood donors in this study; it may not reflect the actual situation in the country.

Serum Cortisol as a Biomarker of Severe Dengue.

Dengue infection presents a wide range of clinical symptoms. Serum cortisol is known as a severity predictor of serious infection but is not yet clearly understood in dengue infection. We aimed to investigate the pattern of cortisol response after dengue infection and evaluate the possibility of using serum cortisol as the biomarker to predict the severity of dengue infection. This prospective study was conducted in Thailand during 2018. Serum cortisol and other laboratory tests were collected at four time points: day 1 at hospital admission, day 3, day of defervescence (DFV) (4-7 days post-fever onset), and day of discharge (DC). The study recruited 265 patients (median age (IQR) 17 (13, 27.5)). Approximately 10% presented severe dengue infection. Serum cortisol levels were highest on the day of admission and day 3. The best cut-off value of serum cortisol level for predicting severe dengue was 18.2 mcg/dL with an AUC of 0.62 (95% CI, 0.51, 0.74). The sensitivity, specificity, PPV and NPV were 65.4, 62.3, 16 and 94%, respectively. When we combined serum cortisol with persistent vomiting and day of fever, the AUC increased to 0.76. In summary, serum cortisol at day of admission was likely to be associated with dengue severity. Further studies may focus on the possibility of using serum cortisol as one of the biomarkers for dengue severity.

Rapid and sensitive point-of-care detection of Leptospira by RPA-CRISPR/Cas12a targeting lipL32.

BACKGROUND: One of the key barriers preventing rapid diagnosis of leptospirosis is the lack of available sensitive point-of-care testing. This study aimed to develop and validate a clustered regularly-interspaced short palindromic repeat (CRISPR)/CRISPR-associated protein 12a (CRISPR/Cas12a) platform combined with isothermal amplification to detect leptospires from extracted patient DNA samples. METHODOLOGY/PRINCIPAL FINDINGS: A Recombinase Polymerase Amplification (RPA)-CRISPR/Cas12a-fluorescence assay was designed to detect the lipL32 gene of pathogenic Leptospira spp. The assays demonstrated a limit of detection (LOD) of 100 cells/mL, with no cross-reactivity against several other acute febrile illnesses. The clinical performance of the assay was validated with DNA extracted from 110 clinical specimens and then compared to results from qPCR detection of Leptospira spp. The RPA-CRISPR/Cas12a assay showed 85.2% sensitivity, 100% specificity, and 92.7% accuracy. The sensitivity increased on days 4-6 after the fever onset and decreased after day 7. The specificity was consistent for several days after the onset of fever. The overall performance of the RPA-CRISPR/Cas12a platform was better than the commercial rapid diagnostic test (RDT). We also developed a lateral flow detection assay (LFDA) combined with RPA-CRISPR/Cas12a to make the test more accessible and easier to interpret. The combined LFDA showed a similar LOD of 100 cells/mL and could correctly distinguish between known positive and negative clinical samples in a pilot study. CONCLUSIONS/SIGNIFICANCE: The RPA-CRISPR/Cas12 targeting the lipL32 gene demonstrated acceptable sensitivity and excellent specificity for detection of leptospires. This assay might be an appropriate test for acute leptospirosis screening in limited-resource settings.

Circulating and urinary microRNAs profile for predicting renal recovery from severe acute kidney injury.

BACKGROUND: There is little known about the contribution of microRNAs (miRNAs) in the recovery from acute kidney injury (AKI). This study aimed to discover and validate miRNA profiles for predicting renal recovery from severe AKI. PATIENTS AND METHODS: A prospective observational study was conducted between June 2020 and January 2021. Urine and serum samples of participants with AKI stage 3 were collected from two groups: renal recovery and renal non-recovery. Transcriptomic analysis was performed using nCounter miRNA Expression Assay. Expression levels of candidate miRNAs were validated using quantitative real-time polymerase chain reaction (qRT-PCR). RESULTS: The discovery phase identified 18 and 11 differentially expressed miRNAs that were statistically significant between the two groups in urine and serum specimens, respectively. Top candidate miRNAs selected included miR-556-3p, miR-1915-3p, miR-4284, miR-32-5p, miR-96-5p, and miR-556-5p in urine, and miR-499b-5p, miR-30a-3p, miR-92b-3p and miR-770-5p in serum. This study enrolled 110 participants in the validation phase. The qRT-PCR analysis indicated that urine miR-556-3p was significantly higher in the renal recovery group than in the renal non-recovery group. Urine miR-556-3p alone predicted renal recovery with an area under the curve (AUC) of 0.64 (95%CI 0.52-0.75, p = 0.03). Combining the clinical model with urine miR-556-3p predicted renal recovery with an AUC of 0.83 (95%CI 0.75-0.92, p < 0.01). CONCLUSION: This data provides evidence that microtranscriptome profiles of severe AKI patients with renal recovery differed from the non-recovery group. Urine miR-556-3p had the potential to improve the prediction of renal recovery from severe AKI.

Discovery and validation of circulating miRNAs for the clinical prognosis of severe dengue.

BACKGROUND: Early prognostic markers of severe dengue may improve case management and reduce dengue-related mortalities. This study aimed to identify circulating microRNAs (miRNAs) as biomarkers for predicting severe dengue. METHODOLOGY: Serum samples from dengue-infected patients were collected on the first day of admission. Patients were followed up for 14 days after admission to determine the final diagnosis. Participants were divided into non-severe and severe dengue, as defined by WHO 2009 criteria. Circulating microtranscriptome analysis was performed using NanoString miRNA Expression Assay. The expression level of candidate miRNAs were then validated by quantitative reverse transcription-PCR method. PRINCIPAL FINDINGS: The discovery cohort (N = 19) lead to the identification of 37 differentially expressed miRNAs between the two groups. Six up-regulated candidate miRNAs were selected and further validated in the larger cohort (N = 135). MiR574-5p and miR1246 displayed the highest diagnostic performance in discriminating between severe from non-severe dengue (ROC-AUC = 0.83). Additionally, miR574-5p and miR1246 had high sensitivity and high negative predictive value for detecting severe dengue. Multivariate analysis suggested that serum miR574-5p was an independent predictor of severe dengue (odds ratio 3.30, 95% CI 1.81-6.04; p<0.001). CONCLUSION: Our study indicated that circulating miRNAs, especially miR-574-5p and miR-1246, might be a promising diagnostic and prognostic biomarker for severe dengue upon hospital admission, especially when using these biomarkers on days 1 to 2 before the onset of severe dengue complications.

Identification and validation of circulating miRNAs as potential new biomarkers for severe liver disease in patients with leptospirosis.

BACKGROUND: Leptospirosis, a global zoonotic infectious disease, has various clinical manifestations ranging from mild self-limiting illness to life-threatening with multi-organ damage, including liver involvement. This study was aimed at identifying circulating microRNAs (miRNAs) as novel biomarkers for predicting severe liver involvement in patients with leptospirosis. METHODS: In a discovery set, 12 serum samples of patients with anicteric and icteric leptospirosis at initial clinical presentation were used for miRNA profiling by a NanoString nCounter miRNA assay. In a validated cohort, top candidate miRNAs were selected and further tested by qRT-PCR in serum samples of 81 and 16 individuals with anicteric and icteric leptospirosis, respectively. RESULTS: The discovery set identified 38 significantly differential expression miRNAs between the two groups. Among these, miR-601 and miR-630 were selected as the top two candidates significantly up-regulated expressed in the icteric group. The enriched KEGG pathway showed that these miRNAs were mainly involved in immune responses and inflammation. In the validated cohort, miR-601 and miR-630 levels were significantly higher in the icteric group compared with the anicteric group. Additionally, these two miRNAs displayed good predictors of subsequent acute liver failure with a high sensitivity of 100%. On regression analysis, elevated miR-601 and miR-630 expression were also predictive of multi-organ failures and poor overall survival. CONCLUSION: Our data indicated that miRNA expression profiles were significantly differentiated between the icteric and anicteric groups. Serum miR-601 and miR-630 at presentation could potentially serve as promising biomarkers for predicting subsequent acute liver failure and overall survival in patients with leptospirosis.

A prospective study to evaluate the accuracy of rapid diagnostic tests for diagnosis of human leptospirosis: Result from THAI-LEPTO AKI study.

BACKGROUND: Rapid diagnostic tests (RDTs) have become widely used in low-resource settings for leptospirosis diagnostic. This study aims to evaluate the diagnostic performance of the five commercially available RDTs to detect human IgM against Leptospira spp. in Thai population. METHODOLOGY/PRINCIPAL FINDINGS: Ninety-nine serum samples from Leptospirosis suspicious patients were tested with five RDTs, including Medical Science Public Health, Leptocheck-WB, SD bioline, TRUSTline, and J.Mitra. The case definition was based on MAT, qPCR, and culture results. Diagnostic accuracy was determined based on the first day of enrollment in an overall analysis and stratified according to days post-onset of fever. The five RDTs had overall sensitivity ranging from 1.8% to 75% and specificity ranging from 52.3% to 97.7%. Leptocheck-WB had high sensitivity of 75.0%. The sensitivity of five RDTs increased on days 4-6 post-onset of fever, while the specificity of all tests remained relatively stable at different days post-onset of fever. CONCLUSIONS/SIGNIFICANCE: The tested RDTs showed low sensitivity. Therefore, based on the present study, five commercially available RDTs might not be an appropriate test for acute leptospirosis screening in the Thai population.

The role of leptospiremia and specific immune response in severe leptospirosis.

Leptospirosis can cause a high mortality rate, especially in severe cases. This multicenter cross-sectional study aimed to examine both host and pathogen factors that might contribute to the disease severity. A total of 217 leptospirosis patients were recruited and divided into two groups of non-severe and severe. Severe leptospirosis was defined by a modified sequential organ failure assessment (mSOFA) score of more than two or needed for mechanical ventilation support or had pulmonary hemorrhage or death. We found that leptospiremia, plasma neutrophil gelatinase-associated lipocalin (pNGAL), and interleukin 6 (IL-6) at the first day of enrollment (day 1) and microscopic agglutination test (MAT) titer at 7 days after enrollment (days 7) were significantly higher in the severe group than in the non-severe group. After adjustment for age, gender, and the days of fever, there were statistically significant associations of baseline leptospiremia level (OR 1.70, 95% CI 1.23-2.34, p = 0.001), pNGAL (OR 9.46, 95% CI 4.20-21.33, p < 0.001), and IL-6 (OR 2.82, 95% CI 1.96-4.07, p < 0.001) with the severity. In conclusion, a high leptospiremia, pNGAL, and IL-6 level at baseline were associated with severe leptospirosis.

Dengue pre-vaccination screening test evaluation for the use of dengue vaccine in an endemic area.

BACKGROUND: The dengue vaccine (Dengvaxia) is only recommended for individuals with prior dengue infection (PDI). This study aimed to perform a serosurvey to inform decision-making for vaccine introduction and identify appropriate target populations. We also evaluated the performance of the serological tests using plaque reduction neutralization test (PRNT) as a reference test in identifying PDI to determine suitability for pre-vaccination screening. METHODS: We enrolled 115 healthy individuals between 10 and 22 years of age living in the Ratchaburi province of Thailand. The serum samples were tested by PRNT to measure the prevalence and concentration of serotype-specific neutralizing antibodies. The performance of the IgG rapid diagnostic test (RDT, SD Bioline, Korea) and IgG enzyme-linked immunosorbent assay (ELISA, EUROIMMUN, Germany) in identifying PDI were evaluated by using PRNT as a reference method. RESULTS: Ninety-four (81.7%) individuals neutralized one or more dengue serotypes at a titer threshold greater than or equal to 10. Multitypic profiles were observed in 70.4% of the samples which increased to 91.9% in subjects aged 19-22. Among monotypic samples, the highest proportion was reactive against DENV-1 followed by DENV-2, DENV-3, and DENV-4. The highest anti-dengue antibody titers were recorded against DENV-1 and increased with age to a geometric mean NT50 titer (GMT) of 188.6 in the 19-22 age group. While both RDT and ELISA exhibited 100% specificity, RDT demonstrated low sensitivity (35%) with ELISA displaying much greater sensitivity (87%). CONCLUSIONS: Almost 80% of adolescents and youth in Ratchaburi province had already been exposed to one or more of the dengue virus serotypes. The dengue IgG RDT displayed low sensitivity and is likely not be suitable for dengue pre-vaccination screening. These results support the use of IgG ELISA test for dengue vaccination in endemic areas.

Circulating microtranscriptome profiles reveal distinct expression of microRNAs in severe leptospirosis.

Biomarkers to predict the severity of leptospirosis are still lacking. This study aimed to identify and validate microRNAs in patients with severe leptospirosis, that could potentially be used as biomarkers for predicting an unfavorable outcome. Serum samples were collected from participants with definite diagnosis of leptospirosis. The participants were divided into two groups, non-severe and severe leptospirosis, as defined by the Specific Organ Sequential Organ Failure (SOFA) Score of more than two in any organ. Microtranscriptome analysis was performed using the NanoString miRNA Expression Assay. The expression level of candidate miRNAs was then validated by quantitative RT-PCR. Based on the NanoString, the microtranscriptome profile of the severe group was significantly different from that of the non-severe group. Upregulation of miR155-5p, miR362-3p, miR502-5p, miR601, miR1323, and miR630 in the severe group were identified, and further investigated. A total of 119 participants were enrolled in the validation cohort. Serum miR155-5p and miR630 levels were significantly higher in the severe group compared to the non-severe group. The combined use of miR155-5p or miR-630 with serum bicarbonate levels had an AUC of 0.79 (95%CI; 0.69-0.89, p<0.001) in identifying the severity of the disease. This data provides the first evidence that the microtranscriptome profiles of patients with severe leptospirosis were different from the non-severe group. Serum miR155-5p and miR630 levels might be novel biomarkers for identifying severe leptospirosis.

Association of vitamin-D-related genetic variations and treatment response to pegylated interferon in patients with chronic hepatitis B.

BACKGROUND: Vitamin D, a potent immune-modulator, has been linked to the pathogenesis of chronic hepatitis B (CHB). This study was aimed at investigating the association between single nucleotide polymorphisms (SNPs) in vitamin-D-related genes and treatment response to pegylated interferon (PEG-IFN) in patients with CHB. METHODS: A total of 275 Thai patients (122 hepatitis B e antigen [HBeAg]-positive and 153 HBeAg-negative CHB) treated with 48-week PEG-IFN were recruited. Virological response (VR) at 48 weeks post-treatment was defined as HBeAg seroconversion plus HBV DNA <2,000 IU/ml for HBeAg-positive CHB and HBV DNA <2,000 IU/ml for HBeAg-negative CHB. The SNPs VDR (rs2228570), DBP (rs7041) and CYP27B1 (rs4646536) were analysed. RESULTS: The distribution of TT, CT and CC genotypes of rs4646536 in this cohort was 21.8%, 46.2% and 32.0%, respectively. There was no difference in its distribution according to HBeAg status. In HBeAg-positive CHB, patients with TT genotype, compared with non-TT genotype, achieved higher VR (53.3% versus 31.5%; P=0.032) and hepatitis B surface antigen (HBsAg) clearance (20.0% versus 5.4%; P=0.016). In HBeAg-negative CHB, the corresponding figures were 60.0% versus 30.9% (P=0.003) and 16.7% versus 5.7% (P=0.045), respectively. Patients with TT genotype had more rapid HBsAg decline than those with non-TT genotype. However, SNPs rs2228570 and rs7041were not associated with VR and HBsAg clearance. Logistic regression analysis demonstrated that SNP rs4646536 and baseline HBsAg level were independent predictors of VR in both HBeAg-positive and HBeAg-negative CHB. CONCLUSIONS: Our data suggest that SNP rs4646536 in the CYP27B1 gene is a predictive factor of response to PEG-IFN therapy in Thai patients with CHB.

Association of interferon-gamma inducible protein 10 polymorphism with treatment response to pegylated interferon in HBeAg-positive chronic hepatitis B.

BACKGROUND: Interferon-gamma inducible protein 10 (IP-10) plays an important role in the clinical outcome of chronic hepatitis B (CHB). This study aimed to investigate the association between single nucleotide polymorphisms (SNPs) G-201A of the IP-10 gene and treatment response to pegylated interferon (PEG-IFN) in patients with hepatitis B e antigen (HBeAg)-positive CHB. METHODS: We retrospectively analysed data of patients with HBeAg-positive CHB treated with PEG-IFN for 48 weeks. Virological response (VR) was defined as HBeAg clearance and HBV DNA <2,000 IU/ml at 24 weeks post-treatment. The SNPs G-201A, IFNL3 (rs12979860) and HLA-DPA1 (rs3077) were assessed. RESULTS: Among 107 patients, VR was achieved in 45 (42.1%) patients. Hepatitis B surface antigen (HBsAg) clearance and decline (<100 IU/ml) were observed in 10 (9.3%) and 22 (20.6%) patients, respectively. The distribution of GG, GA and AA genotypes of G-201A was 76.6%, 19.6% and 3.7%, respectively. Patients with GG genotype, compared to those with non-GG genotype, achieved higher VR rate (48.8% versus 19.2%; P=0.011), decreased HBsAg (25.6% versus 4.0%; P=0.019), and demonstrated a trend in HBsAg clearance (11.0% versus 4%; P=0.294). Patients with GG genotype had more rapid HBsAg decline and higher baseline serum IP-10 levels than those with non-GG genotype (432.2 ±339.0 versus 257.3 ±145.7 pg/ml; P=0.028). SNPs rs12979860 and rs3077 were not associated with VR. Logistic regression analysis suggested that SNP G-201A was an independent predictor of VR (odds ratio 3.81, 95% CI 1.31, 11.12; P=0.014). CONCLUSIONS: Data from this study demonstrated for the first time that IP-10 polymorphism is independently associated with treatment response to PEG-IFN in patients with HBeAg-positive CHB.