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1.
Clin Infect Dis ; 2021 Jan 19.
Artigo em Inglês | MEDLINE | ID: mdl-33462580

RESUMO

BACKGROUND: Dengue is the most significant mosquito-borne viral disease; there are no specific therapeutics. The antiparasitic drug ivermectin efficiently inhibits the replication of all 4 dengue virus serotypes in vitro. METHODS: We conducted 2 consecutive randomized, double-blind, placebo-controlled trials in adult dengue patients to evaluate safety and virological and clinical efficacies of ivermectin. After a phase 2 trial with 2 or 3 days of 1 daily dose of 400 µg/kg ivermectin, we continued with a phase 3, placebo-controlled trial with 3 days of 400 µg/kg ivermectin. RESULTS: The phase 2 trial showed a trend in reduction of plasma nonstructural protein 1 (NS1) clearance time in the 3-day ivermectin group compared with placebo. Combining phase 2 and 3 trials, 203 patients were included in the intention to treat analysis (100 and 103 patients receiving ivermectin and placebo, respectively). Dengue hemorrhagic fever occurred in 24 (24.0%) of ivermectin-treated patients and 32 (31.1%) patients receiving placebo (P = .260). The median (95% confidence interval [CI]) clearance time of NS1 antigenemia was shorter in the ivermectin group (71.5 [95% CI 59.9-84.0] hours vs 95.8 [95% CI 83.9-120.0] hours, P = .014). At discharge, 72.0% and 47.6% of patients in the ivermectin and placebo groups, respectively had undetectable plasma NS1 (P = .001). There were no differences in the viremia clearance time and incidence of adverse events between the 2 groups. CONCLUSIONS: A 3-day 1 daily dose of 400 µg/kg oral ivermectin was safe and accelerated NS1 antigenemia clearance in dengue patients. However, clinical efficacy of ivermectin was not observed at this dosage regimen.

2.
Virol J ; 17(1): 177, 2020 11 13.
Artigo em Inglês | MEDLINE | ID: mdl-33187528

RESUMO

BACKGROUND: The Coronavirus disease 2019 (COVID-19) pandemic continues to spread across the world. Hence, there is an urgent need for rapid, simple, and accurate tests to diagnose severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Performance characteristics of the rapid SARS-CoV-2 antigen detection test should be evaluated and compared with the gold standard real-time reverse transcription-polymerase chain reaction (RT-PCR) test for diagnosis of COVID-19 cases. METHODS: The rapid SARS-CoV-2 antigen detection test, Standard™ Q COVID-19 Ag kit (SD Biosensor®, Republic of Korea), was compared with the real-time RT-PCR test, Allplex™ 2019-nCoV Assay (Seegene®, Korea) for detection of SARS-CoV-2 in respiratory specimens. Four hundred fifty-four respiratory samples (mainly nasopharyngeal and throat swabs) were obtained from COVID-19 suspected cases and contact individuals, including pre-operative patients at Siriraj Hospital, Bangkok, Thailand during March-May 2020. RESULTS: Of 454 respiratory samples, 60 (13.2%) were positive, and 394 (86.8%) were negative for SARS-CoV-2 RNA by real-time RT-PCR assay. The duration from onset to laboratory test in COVID-19 suspected cases and contact individuals ranged from 0 to 14 days with a median of 3 days. The rapid SARS-CoV-2 antigen detection test's sensitivity and specificity were 98.33% (95% CI, 91.06-99.96%) and 98.73% (95% CI, 97.06-99.59%), respectively. One false negative test result was from a sample with a high real-time RT-PCR cycle threshold (Ct), while five false positive test results were from specimens of pre-operative patients. CONCLUSIONS: The rapid assay for SARS-CoV-2 antigen detection showed comparable sensitivity and specificity with the real-time RT-PCR assay. Thus, there is a potential use of this rapid and simple SARS-CoV-2 antigen detection test as a screening assay.

3.
BMC Infect Dis ; 20(1): 817, 2020 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-33167878

RESUMO

BACKGROUND: Gastrointestinal (GI) mucormycosis is a rare and often deadly form of mucormycosis. Delayed diagnosis can lead to an increased risk of death. Here, we report a case of GI mucormycosis following streptococcal toxic shock syndrome in a virologically suppressed HIV-infected patient. CASE PRESENTATION: A 25-year-old Thai woman with a well-controlled HIV infection and Grave's disease was admitted to a private hospital with a high-grade fever, vomiting, abdominal pain, and multiple episodes of mucous diarrhea for 3 days. On day 3 of that admission, the patient developed multiorgan failure and multiple hemorrhagic blebs were observed on all extremities. A diagnosis of streptococcal toxic shock was made before referral to Siriraj Hospital - Thailand's largest national tertiary referral center. On day 10 of her admission at our center, she developed feeding intolerance and bloody diarrhea due to bowel ischemia and perforation. Bowel resection was performed, and histopathologic analysis of the resected bowel revealed acute suppurative transmural necrosis and vascular invasion with numerous broad irregular branching non-septate hyphae, both of which are consistent with GI mucormycosis. Peritoneal fluid fungal culture grew a grayish cottony colony of large non-septate hyphae and spherical sporangia containing ovoidal sporangiospores. A complete ITS1-5.8S-ITS2 region DNA sequence analysis revealed 100% homology with Rhizopus microsporus strains in GenBank (GenBank accession numbers KU729104 and AY803934). As a result, she was treated with liposomal amphotericin B. However and in spite of receiving appropriate treatment, our patient developed recurrent massive upper GI bleeding from Dieulafoy's lesion and succumbed to her disease on day 33 of her admission. CONCLUSION: Diagnosis of gastrointestinal mucormycosis can be delayed due to a lack of well-established predisposing factors and non-specific presenting symptoms. Further studies in risk factors for abdominal mucormycosis are needed.


Assuntos
Trato Gastrointestinal/microbiologia , Doença de Graves/complicações , Infecções por HIV/complicações , Mucormicose/complicações , Rhizopus/genética , Choque Séptico/complicações , Infecções Estreptocócicas/complicações , Streptococcus pyogenes/isolamento & purificação , Adulto , Anfotericina B/uso terapêutico , Antifúngicos/uso terapêutico , DNA Fúngico/genética , Evolução Fatal , Feminino , Infecções por HIV/virologia , Humanos , Mucormicose/diagnóstico , Mucormicose/tratamento farmacológico , Mucormicose/microbiologia , Choque Séptico/diagnóstico , Choque Séptico/microbiologia , Infecções Estreptocócicas/diagnóstico , Infecções Estreptocócicas/microbiologia , Síndrome , Tailândia
4.
BMC Infect Dis ; 20(1): 717, 2020 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-32993529

RESUMO

BACKGROUND: Fungal peritonitis (FP) is a rare complication of peritoneal dialysis. We herein describe the second case in Asia of Histoplasma capsulatum peritonitis associated with continuous ambulatory peritoneal dialysis (CAPD). CASE PRESENTATION: An 85-year-old woman with end-stage renal disease (ESRD) who had been on CAPD for 3 years and who had a history of 3 prior episodes of peritonitis presented with intermittent abdominal pain for 2 weeks and high-grade fever for 3 days. Elevated white blood cell (WBC) count and rare small oval budding yeasts were found in her peritoneal dialysis (PD) fluid. From this fluid, a white mold colony was observed macroscopically after 7 days of incubation, and numerous large, round with rough-walled tuberculate macroconidia along with small smooth-walled microconidia were observed microscopically upon tease slide preparation, which is consistent with H. capsulatum. The peritoneal dialysis (PD) catheter was then removed, and it also grew H. capsulatum after 20 days of incubation. The patient was switched from CAPD to hemodialysis. The patient was successfully treated with intravenous amphotericin B deoxycholate (AmBD) for 2 weeks, followed by oral itraconazole for 6 months with satisfactory result. The patient remains on hemodialysis and continues to be clinically stable. CONCLUSION: H. capsulatum peritonitis is an extremely rare condition that is associated with high morbidity and mortality. Demonstration of small yeasts upon staining of PD fluid, and isolation of slow growing mold in the culture of clinical specimen should provide important clues for diagnosis of H. capsulatum peritonitis. Prompt removal of the PD catheter and empirical treatment with amphotericin B or itraconazole is recommended until the culture results are known.


Assuntos
Histoplasma/isolamento & purificação , Histoplasmose/diagnóstico , Histoplasmose/etiologia , Diálise Peritoneal Ambulatorial Contínua/efeitos adversos , Peritonite/diagnóstico , Peritonite/etiologia , Administração Intravenosa , Administração Oral , Idoso de 80 Anos ou mais , Anfotericina B/administração & dosagem , Anfotericina B/uso terapêutico , Antifúngicos/administração & dosagem , Antifúngicos/uso terapêutico , Ásia , Ácido Desoxicólico/administração & dosagem , Ácido Desoxicólico/uso terapêutico , Combinação de Medicamentos , Feminino , Histoplasmose/tratamento farmacológico , Histoplasmose/microbiologia , Humanos , Itraconazol/administração & dosagem , Itraconazol/uso terapêutico , Falência Renal Crônica/terapia , Peritonite/tratamento farmacológico , Peritonite/microbiologia , Resultado do Tratamento
5.
BMC Infect Dis ; 19(1): 1062, 2019 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-31852453

RESUMO

BACKGROUND: To investigate the cumulative incidence of and factors associated with mortality among patients with infective endocarditis (IE) at Thailand's largest national tertiary referral center. METHODS: Medical charts of adult patients diagnosed with IE by Duke criteria at Siriraj Hospital during January 2005 to May 2015 were retrospectively reviewed. RESULTS: Of 380 patients, 66.3% had definite IE, and 81.3% had native valve IE (NVE). Cumulative IE incidence was 5.67/1000 admissions. The most common pathogens were viridans group streptococci (VGS) (39.7%), methicillin-sensitive Staphylococcus aureus (MSSA) (13.1%), and beta-hemolytic streptococci (11.5%) in NVE; and, MSSA (20.3%), VGS (20.3%), and Enterococcus spp. (16.9%) in prosthetic valve (PVE) or device-related IE (DRIE). Overall in-hospital mortality was 18.4%. Mortality was significantly higher in PVE/DRIE than in NVE (26.8% vs. 16.5%, p = 0.047). End-stage renal disease (ESRD) (aOR: 9.43, 95% CI: 2.36-37.70), diabetes mellitus (DM) (aOR: 2.81, 95% CI: 1.06-7.49), neurological complication (aOR: 14.16, 95% CI: 5.11-39.22), congestive heart failure (aOR: 4.32, 95% CI: 1.91-9.75), hospital-acquired infection (aOR: 3.78, 95% CI: 1.66-8.57), renal complication (aOR: 3.12, 95%CI: 1.32-7.37), and other complication during admission (aOR: 3.28, 95% CI: 1.41-7.61) were independently associated with mortality. CONCLUSIONS: The incidence of IE, and the mortality rate among those diagnosed with IE are both increasing in Thailand - particularly among those with PVE or DRIE. End-stage renal disease, diabetes mellitus, and development of IE-related complications during admission were found to be independent predictors of mortality.


Assuntos
Endocardite Bacteriana/epidemiologia , Enterococcus/isolamento & purificação , Infecções Estafilocócicas/epidemiologia , Staphylococcus aureus/isolamento & purificação , Infecções Estreptocócicas/epidemiologia , Streptococcus/isolamento & purificação , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Infecção Hospitalar , Endocardite Bacteriana/microbiologia , Endocardite Bacteriana/mortalidade , Feminino , Mortalidade Hospitalar , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Infecções Estafilocócicas/microbiologia , Infecções Estafilocócicas/mortalidade , Infecções Estreptocócicas/microbiologia , Infecções Estreptocócicas/mortalidade , Tailândia/epidemiologia , Estreptococos Viridans/isolamento & purificação , Adulto Jovem
6.
Emerg Infect Dis ; 25(9): 1648-1652, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31441427

RESUMO

Mycobacterium haemophilum is a nontuberculous mycobacterium that can infect immunocompromised patients. Because of special conditions required for its culture, this bacterium is rarely reported and there are scarce data for long-term outcomes. We conducted a retrospective study at Siriraj Hospital, Bangkok, Thailand, during January 2012-September 2017. We studied 21 patients for which HIV infection was the most common concurrent condition. The most common organ involvement was skin and soft tissue (60%). Combination therapy with macrolides and fluoroquinolones resulted in a 60% cure rate for cutaneous infection; adding rifampin as a third drug for more severe cases resulted in modest (66%) cure rate. Efficacy of medical therapy in cutaneous, musculoskeletal, and ocular diseases was 80%, 50%, and 50%, respectively. All patients with central nervous system involvement showed treatment failures. Infections with M. haemophilum in HIV-infected patients were more likely to have central nervous system involvement and tended to have disseminated infections and less favorable outcomes.


Assuntos
Infecções por HIV , Hospedeiro Imunocomprometido , Infecções por Mycobacterium/tratamento farmacológico , Mycobacterium haemophilum/isolamento & purificação , Adulto , Idoso , Antibacterianos/uso terapêutico , Estudos de Coortes , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Tailândia , Resultado do Tratamento
7.
Open Forum Infect Dis ; 6(4): ofz132, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31024973

RESUMO

Background: Detection of mycobacterial lipoarabinomannan antigen in urine has emerged as a potential point-of-care test for diagnosis of tuberculosis. This study aimed to evaluate the accuracy of the lateral flow urine lipoarabinomannan (LF-LAM) assay for diagnosis of active tuberculosis among Thai adults with advanced human immunodeficiency virus (HIV) infection. Methods: HIV-infected adult patients with CD4 cell counts ≤200/µL and symptoms suggestive of active tuberculosis were prospectively recruited from both inpatient and outpatient settings at Siriraj Hospital and Chonburi Hospital in Thailand during the study period from December 2015 to March 2017. Freshly collected urine samples were applied to the Alere Determine TB LAM Ag test strip using a grade 1 cutoff, according to the manufacturer's grading system. The diagnostic accuracy of the LF-LAM test was assessed against a microbiological reference standard (definite tuberculosis) or a composite reference standard (definite and probable tuberculosis). Results: Of the 280 patients who were included, 72 (25.7%) had definite and 65 (23.2%) had probable tuberculosis. Among patients with definite tuberculosis, the LF-LAM test yielded a sensitivity of 75.0% and a specificity of 76.0%. It had the highest sensitivity (90.5%) in HIV-infected patients with CD4 cell counts <50/µL. It yielded a lower sensitivity (61.3%) but a higher specificity (86.0%) when compared with the composite reference standard. Among the 20 patients (14%) with false-positive results, strong band intensity was observed mostly in Mycobacterium avium complex infections. An incremental sensitivity of 11% was observed with use of acid-fast bacilli sputum smear or LF-LAM testing, compared with LF-LAM testing alone. Conclusions: The LF-LAM test performed well in the diagnosis of active tuberculosis in selected patients with more advanced tuberculosis and coexisting HIV disease.

8.
PLoS One ; 14(4): e0215581, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31022229

RESUMO

BACKGROUND: Clinical courses and treatment outcomes are largely unknown in patients with adult-onset immunodeficiency associated with anti-interferon-gamma autoantibodies due to the fact that it was recently recognized and anti-IFN-γ auto-Abs detection is not widely available. METHODS AND FINDINGS: Non-HIV-infected adult patients with detectable anti-IFN-γ auto-Abs diagnosed and followed at Siriraj Hospital, Bangkok, Thailand during January 2013 to November 2016 were prospectively studied. At each follow-up visit, patients were classified as stable or active disease according to symptoms and signs, and all proven OIs were recorded. Laboratory parameters, including erythrocyte sedimentation rate, C-reactive protein, and anti-IFN-γ auto-Abs level, were compared between active and stable disease episodes. We identified 80 patients with this clinical syndrome and followed them up during study period. Seventy-nine patients developed overall 194 proven opportunistic infections. Mycobacterium abscessus (34.5%) and Salmonella spp. (23.2%) were the two most common pathogens identified among these patients. Sixty-three patients were followed for a median of 2.7 years (range 0.6-4.8 years). Eleven (17.5%) patients achieved the drug-free remission period for at least 9 months. Four patients died. Anti-IFN-γ auto-Abs concentration was significantly lower at baseline and decreased over time in the drug-free remission group compared to another group (p = 0.001). C-reactive protein, erythrocyte sedimentation rate and white cell count were found to be useful biomarkers for determining disease activity during follow-up. CONCLUSIONS: Reinfection or relapse of OIs is common despite long-term antimicrobial treatment in patients with anti-IFN-γ auto-Abs. Treatment to modify anti-IFN-γ auto-Abs production may improve long-term outcomes in this patient population.


Assuntos
Autoanticorpos/imunologia , Síndromes de Imunodeficiência/imunologia , Infecções por Mycobacterium não Tuberculosas/imunologia , Infecções Oportunistas/imunologia , Infecções por Salmonella/imunologia , Adulto , Idoso , Autoanticorpos/sangue , Biomarcadores/sangue , Sedimentação Sanguínea , Proteína C-Reativa/análise , Feminino , Seguimentos , Humanos , Síndromes de Imunodeficiência/complicações , Síndromes de Imunodeficiência/diagnóstico , Interferon gama/imunologia , Contagem de Linfócitos , Masculino , Pessoa de Meia-Idade , Infecções por Mycobacterium não Tuberculosas/complicações , Infecções por Mycobacterium não Tuberculosas/diagnóstico , Infecções Oportunistas/complicações , Infecções Oportunistas/diagnóstico , Estudos Prospectivos , Recidiva , Infecções por Salmonella/complicações , Infecções por Salmonella/diagnóstico , Tailândia , Adulto Jovem
9.
Artigo em Inglês | MEDLINE | ID: mdl-30533643

RESUMO

We present here the complete genome sequences of Zika virus strains isolated from aborted fetal tissue (brain and placenta) and amniotic fluid of a microcephaly patient in Thailand in 2017. The virus genomes that were sequenced have an average length of 10,807 nucleotides.

10.
BMC Infect Dis ; 18(1): 620, 2018 Dec 04.
Artigo em Inglês | MEDLINE | ID: mdl-30514241

RESUMO

BACKGROUND: Gastrointestinal (GI) cryptococcosis is rarely reported. Most cases were diagnosed during evaluation of comorbid conditions, incidental findings, or postmortem. Here, we present a case of Crohn's disease with gastrointestinal cryptococcosis that resembled exacerbation of Crohn's disease. CASE PRESENTATION: A 64-year-old woman with Crohn's disease (CD) was referred to Siriraj Hospital due to worsening of abdominal pain and watery diarrhea for 2 weeks. The dose of immunosuppressive agents was increased for presumed exacerbation of CD. Pathologic examination of tissue obtained from polypoid mass at ileocecal valve and multiple clean-based ulcers at cecum revealed active ileitis and colitis with multiple round shape organisms with capsule, which was compatible with Cryptococcus species. Disseminated cryptococcosis was diagnosed due to gastrointestinal involvement and presumed pulmonary involvement regarding the presence of an oval-shaped cavitary lesion on chest X-ray and computed tomography of the lung. Patient was successfully treated with amphotericin B followed by fluconazole with satisfactory result. CONCLUSION: Early diagnosis of gastrointestinal cryptococcosis in Crohn's disease is difficult due to the lack of specific symptoms and sign or mimicking an exacerbation of Crohn's disease. Seeking for other site of involvement in disseminated cryptococcosis including lung or central nervous system as well as detection of serum cryptococcal antigen would be helpful for early diagnosis and management.


Assuntos
Doença de Crohn/complicações , Criptococose/complicações , Criptococose/patologia , Gastroenteropatias/complicações , Infecções Fúngicas Invasivas , Anfotericina B/uso terapêutico , Antifúngicos/uso terapêutico , Doença de Crohn/microbiologia , Doença de Crohn/patologia , Criptococose/diagnóstico , Criptococose/tratamento farmacológico , Progressão da Doença , Feminino , Fluconazol/uso terapêutico , Gastroenteropatias/microbiologia , Gastroenteropatias/patologia , Humanos , Imunossupressores/efeitos adversos , Infecções Fúngicas Invasivas/complicações , Infecções Fúngicas Invasivas/diagnóstico , Infecções Fúngicas Invasivas/patologia , Pessoa de Meia-Idade , Tomografia Computadorizada por Raios X
11.
Emerg Infect Dis ; 24(9)2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-29985788

RESUMO

We sequenced the virus genomes from 3 pregnant women in Thailand with Zika virus diagnoses. All had infections with the Asian lineage. The woman infected at gestational week 9, and not those infected at weeks 20 and 24, had a fetus with microcephaly. Asian lineage Zika viruses can cause microcephaly.


Assuntos
Microcefalia/diagnóstico , Complicações Infecciosas na Gravidez , Infecção por Zika virus , Zika virus/isolamento & purificação , Feminino , Humanos , Recém-Nascido , Microcefalia/etiologia , Gravidez , Primeiro Trimestre da Gravidez , Tailândia , Zika virus/genética
12.
PLoS One ; 13(2): e0193431, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29470531

RESUMO

BACKGROUND: The incidence of nosocomial infections from extensively drug-resistant Pseudomonas aeruginosa (XDR-PA) has been increasing worldwide. We investigated the prevalence and factors associated with XDR-PA infections, including the factors that predict mortality. METHODS: We retrospectively studied a cohort of adult, hospitalized patients with P. aeruginosa (PA) infections between April and December 2014. RESULTS: Of the 255 patients with PA infections, 56 (22%) were due to XDR-PA, 32 (12.5%) to multidrug resistant Pseudomonas aeruginosa (MDR-PA), and 167 (65.5%) to non-MDR PA. Receiving total parenteral nutrition (adjusted OR [aOR] 6.21; 95% CI 1.05-36.70), prior carbapenem use (aOR 4.88; 95% CI 2.36-10.08), and prior fluoroquinolone use (aOR 3.38; 95% CI 1.44-7.97) were independently associated with the XDR-PA infections. All XDR-PA remained susceptible to colistin. Factors associated with mortality attributable to the infections were the presence of sepsis/septic shock (aOR 11.60; 95% CI 4.66-28.82), admission to a medical department (aOR 4.67; 95% CI 1.81-12.06), receiving a central venous catheter (aOR 3.78; 95% CI 1.50-9.57), and XDR-PA infection (aOR 2.73; 95% CI 1.05-7.08). CONCLUSION: The prevalence of XDR-PA infections represented almost a quarter of Pseudomonas aeruginosa hospital-acquired infections and rendered a higher mortality. The prompt administration of an appropriate empirical antibiotic should be considered when an XDR-PA infection is suspected.


Assuntos
Antibacterianos/uso terapêutico , Infecção Hospitalar/epidemiologia , Farmacorresistência Bacteriana Múltipla , Infecções por Pseudomonas/epidemiologia , Idoso , Idoso de 80 Anos ou mais , Antibacterianos/farmacologia , Infecção Hospitalar/tratamento farmacológico , Feminino , Hospitalização , Humanos , Masculino , Pessoa de Meia-Idade , Prevalência , Infecções por Pseudomonas/tratamento farmacológico , Pseudomonas aeruginosa/efeitos dos fármacos , Estudos Retrospectivos , Fatores de Risco
13.
J Virol ; 90(24): 11259-11278, 2016 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-27707928

RESUMO

Epidemiological studies suggest that India has the largest number of dengue virus infection cases worldwide. However, there is minimal information about the immunological responses in these patients. CD8 T cells are important in dengue, because they have been implicated in both protection and immunopathology. Here, we provide a detailed analysis of HLA-DR+ CD38+ and HLA-DR- CD38+ effector CD8 T cell subsets in dengue patients from India and Thailand. Both CD8 T cell subsets expanded and expressed markers indicative of antigen-driven proliferation, tissue homing, and cytotoxic effector functions, with the HLA-DR+ CD38+ subset being the most striking in these effector qualities. The breadth of the dengue-specific CD8 T cell response was diverse, with NS3-specific cells being the most dominant. Interestingly, only a small fraction of these activated effector CD8 T cells produced gamma interferon (IFN-γ) when stimulated with dengue virus peptide pools. Transcriptomics revealed downregulation of key molecules involved in T cell receptor (TCR) signaling. Consistent with this, the majority of these CD8 T cells remained IFN-γ unresponsive even after TCR-dependent polyclonal stimulation (anti-CD3 plus anti-CD28) but produced IFN-γ by TCR-independent polyclonal stimulation (phorbol 12-myristate 13-acetate [PMA] plus ionomycin). Thus, the vast majority of these proliferating, highly differentiated effector CD8 T cells probably acquire TCR refractoriness at the time the patient is experiencing febrile illness that leads to IFN-γ unresponsiveness. Our studies open novel avenues for understanding the mechanisms that fine-tune the balance between CD8 T cell-mediated protective versus pathological effects in dengue. IMPORTANCE: Dengue is becoming a global public health concern. Although CD8 T cells have been implicated both in protection and in the cytokine-mediated immunopathology of dengue, how the balance is maintained between these opposing functions remains unknown. We comprehensively characterized CD8 T cell subsets in dengue patients from India and Thailand and show that these cells expand massively and express phenotypes indicative of overwhelming antigenic stimulus and tissue homing/cytotoxic-effector functions but that a vast majority of them fail to produce IFN-γ in vitro Interestingly, the cells were fully capable of producing the cytokine when stimulated in a T cell receptor (TCR)-independent manner but failed to do so in TCR-dependent stimulation. These results, together with transcriptomics, revealed that the vast majority of these CD8 T cells from dengue patients become cytokine unresponsive due to TCR signaling insufficiencies. These observations open novel avenues for understanding the mechanisms that fine-tune the balance between CD8-mediated protective versus pathological effects.


Assuntos
Linfócitos T CD8-Positivos/imunologia , Citotoxicidade Imunológica , Vírus da Dengue/efeitos dos fármacos , Subpopulações de Linfócitos T/imunologia , Transcriptoma/imunologia , ADP-Ribosil Ciclase 1/genética , ADP-Ribosil Ciclase 1/imunologia , Adolescente , Anticorpos/farmacologia , Antígenos CD28/antagonistas & inibidores , Antígenos CD28/genética , Antígenos CD28/imunologia , Complexo CD3/genética , Complexo CD3/imunologia , Linfócitos T CD8-Positivos/efeitos dos fármacos , Linfócitos T CD8-Positivos/virologia , Proliferação de Células/efeitos dos fármacos , Criança , Pré-Escolar , Vírus da Dengue/genética , Vírus da Dengue/crescimento & desenvolvimento , Vírus da Dengue/metabolismo , Feminino , Regulação da Expressão Gênica , Antígenos HLA-DR/genética , Antígenos HLA-DR/imunologia , Humanos , Imunidade Celular , Índia , Lactente , Interferon gama/genética , Interferon gama/imunologia , Ionomicina/farmacologia , Masculino , Glicoproteínas de Membrana/genética , Glicoproteínas de Membrana/imunologia , Cultura Primária de Células , RNA Helicases/genética , RNA Helicases/imunologia , Receptores de Antígenos de Linfócitos T/genética , Receptores de Antígenos de Linfócitos T/imunologia , Serina Endopeptidases/genética , Serina Endopeptidases/imunologia , Transdução de Sinais , Subpopulações de Linfócitos T/efeitos dos fármacos , Subpopulações de Linfócitos T/virologia , Acetato de Tetradecanoilforbol/farmacologia , Proteínas não Estruturais Virais/genética , Proteínas não Estruturais Virais/imunologia
14.
J Virol ; 90(12): 5574-85, 2016 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-27030262

RESUMO

UNLABELLED: Dengue virus (DENV) infection results in the production of both type-specific and cross-neutralizing antibodies. While immunity to the infecting serotype is long-lived, heterotypic immunity wanes a few months after infection. Epidemiological studies link secondary heterotypic infections with more severe symptoms, and cross-reactive, poorly neutralizing antibodies have been implicated in this increased disease severity. To understand the cellular and functional properties of the acute dengue virus B cell response and its role in protection and immunopathology, we characterized the plasmablast response in four secondary DENV type 2 (DENV2) patients. Dengue plasmablasts had high degrees of somatic hypermutation, with a clear preference for replacement mutations. Clonal expansions were also present in each donor, strongly supporting a memory origin for these acutely induced cells. We generated 53 monoclonal antibodies (MAbs) from sorted patient plasmablasts and found that DENV-reactive MAbs were largely envelope specific and cross neutralizing. Many more MAbs neutralized DENV than reacted to envelope protein, emphasizing the significance of virion-dependent B cell epitopes and the limitations of envelope protein-based antibody screening. A majority of DENV-reactive MAbs, irrespective of neutralization potency, enhanced infection by antibody-dependent enhancement (ADE). Interestingly, even though DENV2 was the infecting serotype in all four patients, several MAbs from two patients neutralized DENV1 more potently than DENV2. Further, half of all type-specific neutralizing MAbs were also DENV1 biased in binding. Taken together, these findings are reminiscent of original antigenic sin (OAS), given that the patients had prior dengue virus exposures. These data describe the ongoing B cell response in secondary patients and may further our understanding of the impact of antibodies in dengue virus pathogenesis. IMPORTANCE: In addition to their role in protection, antibody responses have been hypothesized to contribute to the pathology of dengue. Recent studies characterizing memory B cell (MBC)-derived MAbs have provided valuable insight into the targets and functions of B cell responses generated after DENV exposure. However, in the case of secondary infections, such MBC-based approaches fail to distinguish acutely induced cells from the preexisting MBC pool. Our characterization of plasmablasts and plasmablast-derived MAbs provides a focused analysis of B cell responses activated during ongoing infection. Additionally, our studies provide evidence of OAS in the acute-phase dengue virus immune response, providing a basis for future work examining the impact of OAS phenotype antibodies on protective immunity and disease severity in secondary infections.


Assuntos
Anticorpos Antivirais/imunologia , Linfócitos B/imunologia , Reações Cruzadas , Vírus da Dengue/imunologia , Dengue/imunologia , Memória Imunológica , Adolescente , Adulto , Anticorpos Monoclonais/imunologia , Anticorpos Neutralizantes/imunologia , Anticorpos Facilitadores , Dengue/fisiopatologia , Dengue/virologia , Epitopos de Linfócito B , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Plasmócitos/imunologia , Sorogrupo , Proteínas do Envelope Viral/imunologia , Adulto Jovem
15.
PLoS One ; 10(5): e0128481, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26011559

RESUMO

Recently a newly identified clinical syndrome of disseminated non-tuberculous mycobacterial diseases (with or without other opportunistic infections in adult patients who were previously healthy, has been recognized in association with an acquired autoantibody to interferon-gamma. This syndrome is emerging as an important cause of morbidity and mortality, especially among people of Asian descent. Trigger for the production of this autoantibody remains unknown, but genetic factors are strongly suspected to be involved. We compared HLA genotyping between 32 patients with this clinical syndrome, and 38 controls. We found that this clinical syndrome was associated with very limited allele polymorphism, with HLA-DRB1 and DQB1 alleles, especially HLA-DRB1*15:01, DRB1*16:02, DQB1*05:01 and DQB1*05:02. Odds ratio of DRB1*15:01, DRB1*16:02, DQB1*05:01 and DQB1*05:02 were 7.03 (95% CI, 2.18-22.69, P<0.0001, 9.06 (95% CI, 2.79-29.46, P<0.0001), 6.68 (95% CI, 2.29-19.52, P = 0.0004), and 6.64 (95% CI, 2.30-19.20, P = 0.0004), respectively. Further investigation is warranted to provide better understanding on pathogenesis of this association.


Assuntos
Autoanticorpos/sangue , Cadeias beta de HLA-DQ/genética , Cadeias HLA-DRB1/genética , Interferon gama/imunologia , Infecções por Mycobacterium não Tuberculosas/genética , Adulto , Idade de Início , Idoso , Grupo com Ancestrais do Continente Asiático/genética , Feminino , Estudos de Associação Genética , Humanos , Masculino , Pessoa de Meia-Idade , Infecções por Mycobacterium não Tuberculosas/sangue , Infecções por Mycobacterium não Tuberculosas/imunologia , Polimorfismo Genético , Tailândia
16.
PLoS Negl Trop Dis ; 8(12): e3342, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25522230

RESUMO

BACKGROUND: Carrion' disease, caused by Bartonella bacilliformis, remains truly neglected due to its focal geographical nature. A wide spectrum of clinical manifestations, including asymptomatic bacteremia, and lack of a sensitive diagnostic test can potentially lead to a spread of the disease into non-endemic regions where competent sand fly vectors may be present. A reliable test capable of detecting B. bacilliformis is urgently needed. Our objective is to develop a loop-mediated isothermal amplification (LAMP) assay targeting the pap31 gene to detect B. bacilliformis. METHODS AND FINDINGS: The sensitivity of the LAMP was evaluated in comparison to qPCR using plasmid DNA containing the target gene and genomic DNA in the absence and presence of human or sand fly DNA. The detection limit of LAMP was 1 to 10 copies/µL, depending on the sample metrics. No cross-reaction was observed when testing against a panel of various closely related bacteria. The utility of the LAMP was further compared to qPCR by the examination of 74 Lutzomyia longipalpis sand flies artificially fed on blood spiked with B. bacilliformis and harvested at days (D) 1, 3, 5, 7 and 9 post feeding. Only 86% of sand flies at D1 and 63% of flies at D3 were positive by qPCR. LAMP was able to detect B. bacilliformis in all those flies confirmed positive by qPCR. However, none of the flies after D3 were positive by either LAMP or qPCR. In addition to demonstrating the sensitivity of the LAMP assay, these results suggest that B. bacilliformis cannot propagate in artificially fed L. longipalpis. CONCLUSIONS: The LAMP assay is as sensitive as qPCR for the detection of B. bacilliformis and could be useful to support diagnosis of patients in low-resource settings and also to identify B. bacilliformis in the sand fly vector.


Assuntos
Bartonella bacilliformis/isolamento & purificação , Insetos Vetores/microbiologia , Técnicas de Amplificação de Ácido Nucleico/métodos , Psychodidae/microbiologia , Animais , Infecções por Bartonella/microbiologia , Infecções por Bartonella/transmissão , Bartonella bacilliformis/genética , DNA Bacteriano/análise , DNA Bacteriano/genética , Feminino , Sensibilidade e Especificidade
17.
Infect Immun ; 82(9): 3880-90, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-24980974

RESUMO

Cryptococcal infections are primarily caused by two related fungal species: Cryptococcus neoformans and Cryptococcus gattii. It is well known that C. neoformans generally affects immunocompromised hosts; however, C. gattii infection can cause diseases in not only immunocompromised hosts but also immunocompetent individuals. While recent studies suggest that C. gattii infection could dampen pulmonary neutrophil recruitment and inflammatory cytokine production in immunocompetent hosts, the impact of C. gattii infection on the development of their adaptive T helper cell immune response has not been addressed. Here, we report that C. neoformans infection with highly virulent and less virulent strains preferentially induced pulmonary Th1 and Th17 immune responses in the host, respectively. However, fewer pulmonary Th1 and Th17 cells could be detected in mice infected with C. gattii strains. Notably, dendritic cells (DC) in mice infected with C. gattii expressed much lower levels of surface MHC-II and Il12 or Il23 transcripts and failed to induce effective Th1 and Th17 differentiation in vitro. Furthermore, the expression levels of Ip10 and Cxcl9 transcripts, encoding Th1-attracting chemokines, were significantly reduced in the lungs of mice infected with the highly virulent C. gattii strain. Thus, our data suggest that C. gattii infection dampens the DC-mediated effective Th1/Th17 immune responses and downregulates the pulmonary chemokine expression, thus resulting in the inability to mount protective immunity in immunocompetent hosts.


Assuntos
Quimiocinas/imunologia , Criptococose/imunologia , Cryptococcus gattii/imunologia , Células Dendríticas/imunologia , Pulmão/imunologia , Células Th1/imunologia , Células Th17/imunologia , Animais , Criptococose/microbiologia , Células Dendríticas/microbiologia , Regulação para Baixo/imunologia , Feminino , Pulmão/microbiologia , Camundongos , Camundongos Endogâmicos C57BL , Células Th1/microbiologia , Células Th17/microbiologia
18.
Am J Trop Med Hyg ; 90(4): 690-6, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24515944

RESUMO

Reliable laboratory testing is of great importance to detect Bartonella bacilliformis infection. We evaluated the sensitivity and specificity of the enzyme-linked immunosorbent assay (ELISA) using recombinant protein Pap31 (rPap31) for the detection of antibodies against B. bacilliformis as compared with immunofluorescent assay (IFA). Of the 302 sera collected between 1997 and 2000 among an at-risk Peruvian population, 103 and 34 samples tested positive for IFA-immunoglobulin G (IgG) and IFA-IgM, respectively. By using Youden's index, the cutoff values of ELISA-IgG at 0.915 gave a sensitivity of 84.5% and specificity of 94%. The cutoff values of ELISA-IgM at 0.634 gave a sensitivity of 88.2% and specificity of 85.1%. Using latent class analysis, estimates of sensitivity and specificity of almost all the assays were slightly higher than those of a conventional method of calculation. The test is proved beneficial for discriminating between infected and non-infected individuals with the advantage of low-cost and high-throughput capability.


Assuntos
Anticorpos Antibacterianos/imunologia , Antígenos de Bactérias , Infecções por Bartonella/diagnóstico , Bartonella bacilliformis/imunologia , Ensaio de Imunoadsorção Enzimática , Imunoglobulina G/imunologia , Imunoglobulina M/imunologia , Técnica Indireta de Fluorescência para Anticorpo , Humanos , Peru , Proteínas Recombinantes/imunologia , Sensibilidade e Especificidade
19.
PLoS One ; 8(11): e81436, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24312299

RESUMO

BACKGROUND: Little is known about the dynamics or magnitude of antibody response in patients with influenza A (H1N1) pdm09-associated pneumonia. We described and compared the antibody response to influenza A (H1N1) pdm09 in patients with and without pneumonia. METHODS: We collected serum samples and determined antibody titers by the hemagglutination inhibition (HI) and microneutralization (mNT) assays from patients with RT-PCR confirmed influenza A (H1N1) pdm09 virus at baseline, 1, 2 and 6 months after onset of illness. RESULTS: Fifty-nine patients were enrolled, 45 (76.3%) were between 15 and 60 years of age, 49 (83.1%) were hospitalized and 25 (42.4%) had complications with pneumonia. Ninety-four percent of patients had HI titers ≥ 1: 40 and 90% had mNT titers ≥ 1: 160 at 2 months after illness. Geometric mean titers (GMT) of HI and mNT increased significantly (p<0.001) between baseline and months 1 or 2, then declined significantly (p<0.001) at month 6 by the HI assay, but dropped to an insignificant level (p=0.24) by the mNT assay. The mNT-GMT was at least twice as high as corresponding HI antibodies over a 6 month period. The GMT of HI and mNT in those with pneumonia (1 mo) peaked earlier than that of those without pneumonia (2 mo). When adjusted by age and gender, those with pneumonia had a higher HI-GMT than those without pneumonia at 1 month (264 vs. 117, p=0.007), 2 months (212 vs. 159, p=0.013), and 6 months (160 vs. 82, p=0.018). CONCLUSIONS: The patients recovered from influenza A (H1N1) pdm09-associated pneumonia, clearly developed an earlier and more robust antibody response until 6 months after onset of illness. The results in our study are useful to determine an appropriate donor and timing to obtain convalescent plasma for adjunctive treatment of seriously ill patients with pandemic H1N1 influenza.


Assuntos
Vírus da Influenza A Subtipo H1N1/fisiologia , Influenza Humana/complicações , Influenza Humana/imunologia , Pneumonia/complicações , Adolescente , Adulto , Anticorpos Antivirais/sangue , Anticorpos Antivirais/imunologia , Criança , Pré-Escolar , Feminino , Humanos , Influenza Humana/sangue , Masculino , Pessoa de Meia-Idade , Gravidez , Testes Sorológicos , Adulto Jovem
20.
J Immunol ; 190(8): 3959-66, 2013 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-23509356

RESUMO

Cryptococcal meningitis has been described in immunocompromised patients, as well as in those for whom no immune defect has been identified. GM-CSF regulates the function of phagocytes and pulmonary alveolar macrophages, critical elements in cryptococcal control. We performed clinical histories, immunological evaluation, and anticytokine autoantibody screening in four current patients with cryptococcal meningitis and identified and tested 103 archived plasma/cerebrospinal fluid samples from patients with cryptococcal meningitis. We assessed the ability of anti-GM-CSF autoantibody-containing plasmas to inhibit GM-CSF signaling. We recognized anti-GM-CSF autoantibodies in an otherwise healthy female with cryptococcal meningitis who later developed pulmonary alveolar proteinosis (PAP). Her diagnosis prompted screening of patients with cryptococcal meningitis for anticytokine autoantibodies. We identified seven HIV-negative patients with cryptococcal meningitis who tested positive for high-titer anti-GM-CSF autoantibodies. Two of the seven later developed evidence of PAP. Plasma from all patients prevented GM-CSF-induced STAT5 phosphorylation and MIP-1α production in normal PBMCs. This effect was limited to their IgG fraction. Anti-GM-CSF autoantibodies are associated with some cases of cryptococcal meningitis in otherwise immunocompetent patients. These cases need not have associated PAP.


Assuntos
Autoanticorpos/sangue , Fator Estimulador de Colônias de Granulócitos e Macrófagos/imunologia , Meningite Criptocócica/imunologia , Adulto , Autoanticorpos/biossíntese , Autoanticorpos/fisiologia , Feminino , Fator Estimulador de Colônias de Granulócitos e Macrófagos/sangue , Fator Estimulador de Colônias de Granulócitos e Macrófagos/líquido cefalorraquidiano , Humanos , Imunoglobulina G/biossíntese , Imunoglobulina G/sangue , Imunoglobulina G/fisiologia , Masculino , Meningite Criptocócica/metabolismo , Pessoa de Meia-Idade , Fator de Transcrição STAT5/antagonistas & inibidores , Adulto Jovem
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