Browsing by Subject "Talaromycosis"
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Item Open Access Pulmonary Talaromycosis: A Window into the Immunopathogenesis of an Endemic Mycosis.(Mycopathologia, 2021-07-06) Narayanasamy, Shanti; Dougherty, John; van Doorn, H Rogier; Le, ThuyTalaromycosis is an invasive mycosis caused by the thermally dimorphic saprophytic fungus Talaromyces marneffei (Tm) endemic in Asia. Like other endemic mycoses, talaromycosis occurs predominantly in immunocompromised and, to a lesser extent, immunocompetent hosts. The lungs are the primary portal of entry, and pulmonary manifestations provide a window into the immunopathogenesis of talaromycosis. Failure of alveolar macrophages to destroy Tm results in reticuloendothelial system dissemination and multi-organ disease. Primary or secondary immune defects that reduce CD4+ T cells, INF-γ, IL-12, and IL-17 functions, such as HIV infection, anti-interferon-γ autoantibodies, STAT-1 and STAT-3 mutations, and CD40 ligand deficiency, highlight the central roles of Th1 and Th17 effector cells in the control of Tm infection. Both upper and lower respiratory infections can manifest as localised or disseminated disease. Upper respiratory disease appears unique to talaromycosis, presenting with oropharyngeal lesions and obstructive tracheobronchial masses. Lower respiratory disease is protean, including alveolar consolidation, solitary or multiple nodules, mediastinal lymphadenopathy, cavitary disease, and pleural effusion. Structural lung disease such as chronic obstructive pulmonary disease is an emerging risk factor in immunocompetent hosts. Mortality, up to 55%, is driven by delayed or missed diagnosis. Rapid, non-culture-based diagnostics including antigen and PCR assays are shown to be superior to blood culture for diagnosis, but still require rigorous clinical validation and commercialisation. Our current understanding of acute pulmonary infections is limited by the lack of an antibody test. Such a tool is expected to unveil a larger disease burden and wider clinical spectrum of talaromycosis.Item Open Access Superiority of a novel Mp1p antigen detection enzyme immunoassay compared to standard BACTEC blood culture in the diagnosis of talaromycosis.(Clinical infectious diseases : an official publication of the Infectious Diseases Society of America, 2020-06-21) Thu, Nguyen TM; Chan, Jasper FW; Ly, Vo Trieu; Ngo, Hoa T; Hien, Ha TA; Lan, Nguyen PH; Chau, Nguyen VV; Cai, Jian-Piao; Woo, Patrick CY; Day, Jeremy N; van Doorn, Rogier; Thwaites, Guy; Perfect, John; Yuen, Kwok; Le, ThuyBACKGROUND:Talaromycosis is an invasive mycosis endemic in Southeast Asia and causes substantial morbidity and mortality in individuals with advanced HIV disease. Current diagnosis relies on isolating Talaromyces marneffei in cultures, which takes up to 14 days and is detectable only during late-stage infection, leading to high mortality. METHODS:In this retrospective case-control study, we assessed the accuracy of a novel Mp1p antigen-detecting enzyme immunoassay (EIA) in stored plasma samples of 372 patients who had culture-proven talaromycosis from blood or sterile body fluids(reference standard) and of 517 individuals without talaromycosis (338 healthy volunteers; 179 with other infections). All participants were recruited between 2011-2017 in Vietnam. RESULTS:66.1% and 75.4% of cases and controls were male; the median age was 33 and 37, respectively. All cases were HIV-infected; median CD4 count was 10 cells/mm3. At an optical density cut-off of 0.5, the specificity was 98.1% (95% CI: 96.3%-99.0%); the sensitivity was superior to blood culture, 86.3% (95% CI: 82.3%-89.5%) versus 72.8% (95% CI: 68.0%-77.2%), P<0.001, McNemar test. The time-to-diagnosis was 6 hours versus 6.6 ± 3.0 days for blood culture. Paired plasma and urine testing in the same patients (N=269) significantly increased sensitivity compared to testing plasma alone P<0.001, or testing urine alone P=0.02, McNemar tests. CONCLUSIONS:The Mp1p EIA is highly specific and is superior in sensitivity and time-to-diagnosis compared to blood culture for the diagnosis of talaromycosis. Paired plasma and urine testing further increases sensitivity, introducing a new tool for rapid diagnosis, enabling early treatment and potentially reducing mortality.