Infectious disease
Abstract
BACKGROUND Current diagnostic tools for tuberculous pleural effusion (TPE) are often inadequate, making accurate diagnosis challenging. Effective identification of TPE is critical for ensuring proper treatment and preventing tuberculosis relapse. This study explored the potential of granzyme A (GZMA) as a biomarker for TPE.METHODS Patients with TPE, malignant pleural effusion (MPE), and parapneumonic pleural effusion (PPE) were recruited into discovery and validation cohorts. The discovery cohort consisted of 200 patients with TPE and 100 patients with MPE, while the validation cohort included 167 patients with TPE, 84 patients with MPE, and 69 patients with PPE.RESULTS In the discovery cohort, GZMA levels were significantly elevated in TPE compared with MPE, demonstrating 90% sensitivity and 91% specificity at a cutoff of 102.29 ng/mL for effectively distinguishing between the two conditions. In the validation cohort, GZMA maintained high diagnostic performance, distinguishing TPE from MPE with 87% sensitivity and 87% specificity and from PPE with 87% sensitivity and 84% specificity. Incorporating GZMA, lactate dehydrogenase (LDH), and adenosine deaminase (ADA) into a random forest model further improved diagnostic accuracy. In the discovery cohort, this model achieved 92% sensitivity and 100% specificity, and in the validation cohort, it distinguished TPE from MPE with 87% sensitivity and 94% specificity and from PPE with 87% sensitivity and 91% specificity.CONCLUSION Overall, GZMA is a promising biomarker for diagnosing TPE, with improved accuracy when combined with LDH and ADA, providing a robust tool for timely identification and effective management of patients with TPE.FUNDING The study was supported by Science and Technology Project of Shenzhen (KCXFZ20211020163545004, KQTD20210811090219022, JCYJ20220818095610021, JSGG20220822095200001, JCYJ20210324094614038), Shenzhen Medical Research Funding (B2302035, A2302004), Provincial Natural Science Foundation of Guangdong (2022A1515220034), and Shenzhen Third People’s Hospital Research Foundation (G2022155).
Authors
Fuxiang Li, Chuanzhi Zhu, Yue Zhang, Fanhui Kong, Ximeng Zhang, Liping Pan, Hongyan Jia, Liang Fu, Yunlong Hu, Guofang Deng, Qianting Yang, Xinchun Chen, Yi Cai
Abstract
Despite effective treatment, Human immunodeficiency virus (HIV) persists in optimally treated people as a transcriptionally silent provirus. Latently infected cells evade the immune system and the harmful effects of the virus, thereby creating a long-lasting reservoir of HIV. To gain a deeper insight into the molecular mechanisms of HIV latency establishment, we constructed a series of HIV-1 fluorescent reporter viruses that distinguish active versus latent infection. We unexpectedly observed that the proportion of active-to-latent infection depended on a limiting viral factor, which created a bottle neck that could be overcome by superinfection of the cell, T cell activation or overexpression of HIV-1 trans activator of transcription (Tat). In addition, we found that tat and rev expression levels vary amongst HIV molecular clones and that tat levels were an important variable in latency establishment. Lower rev levels limited viral protein expression whereas lower Tat levels or mutation of the Tat binding element promoted latent infection that was resistant to reactivation even in fully activated primary T cells. Nevertheless, we found that combinations of latency reversal agents targeting both cellular activation and histone acetylation pathways overcame deficiencies in the Tat-TAR axis of transcription regulation. These results provide additional insight into the mechanisms of latency establishment and inform Tat-centered approaches to cure HIV.
Authors
Francisco Gomez-Rivera, Valeri H. Terry, Cuie Chen, Mark M. Painter, Maria C. Virgilio, Marianne E. Yaple-Maresh, Kathleen L. Collins
Abstract
Urinary neutrophils are a hallmark of urinary tract infection (UTI), yet the mechanisms governing their activation, function, and efficacy in controlling infection remain incompletely understood. Tamm-Horsfall glycoprotein (THP), the most abundant protein in urine, uses terminal sialic acids to bind an inhibitory receptor and dampen neutrophil inflammatory responses. We hypothesized that neutrophil modulation is an integral part of THP-mediated host protection. In a UTI model, THP-deficient mice showed elevated urinary tract bacterial burdens, increased neutrophil recruitment, and more severe tissue histopathological changes compared to WT mice. Furthermore, THP-deficient mice displayed impaired urinary NETosis during UTI. To investigate the impact of THP on NETosis, we coupled in vitro fluorescence-based NET assays, proteomic analyses, and standard and imaging flow cytometry with peripheral human neutrophils. We found that THP increases proteins involved in respiratory chain, neutrophil granules, and chromatin remodeling pathways, enhances NETosis in an ROS-dependent manner, and drives NET-associated morphologic features including nuclear decondensation. These effects were observed only in the presence of a NETosis stimulus and could not be solely replicated with equivalent levels of sialic acid alone. We conclude that THP is a critical regulator of NETosis in the urinary tract, playing a key role in host defense against UTI.
Authors
Vicki Mercado-Evans, Holly Branthoover, Claude Chew, Camille Serchejian, Alexander B. Saltzman, Marlyd E. Mejia, Jacob J. Zulk, Ingrid Cornax, Victor Nizet, Kathryn A. Patras
Abstract
CD4+ T helper 1 (TH1) cells coordinate adaptive immune responses to intracellular pathogens, including viruses. Key to this function is the ability of TH1 cells to migrate within secondary lymphoid tissues, as well as to sites of inflammation, which relies on signals received through the chemokine receptor CXCR3. CXCR3 expression is driven by the TH1 lineage-defining transcription factor T-bet, and the cytokine-responsive Signal Transducer and Activator of Transcription (STAT) family members STAT1 and STAT4. Here, we identify the Ikaros zinc finger (IkZF) transcription factor Aiolos (Ikzf3) as an additional positive regulator of CXCR3 both in vitro and in vivo using a murine model of influenza virus infection. Mechanistically, we find that Aiolos-deficient CD4+ T cells exhibit decreased expression of key components of the IFNγ/STAT1 signaling pathway, including JAK2 and STAT1. Consequently, Aiolos deficiency results in decreased levels of STAT1 tyrosine phosphorylation and reduced STAT1 enrichment at the Cxcr3 promoter. We further find that Aiolos and STAT1 form a positive feedback loop via reciprocal regulation of each other downstream of IFNγ signaling. Collectively, our study demonstrates that Aiolos promotes CXCR3 expression on TH1 cells by propagating the IFNγ/STAT1 cytokine signaling pathway.
Authors
Melissa R. Leonard, Devin M. Jones, Kaitlin A. Read, Srijana Pokhrel, Jasmine A. Tuazon, Robert T. Warren, Jacob S. Yount, Kenneth J. Oestreich
Abstract
BACKGROUND Despite the currently prevailing, milder Omicron variant of COVID-19, older adults remain at elevated risk of hospital admission, critical illness, and death. Loss of efficacy of the immune system, including reduced strength, quality, and durability of antibody responses, may render generalized recommendations on booster vaccinations inadequate. There is a lack of data on the efficacy of antibody levels in older adults and on the utility of vaccination status versus antibody levels as a correlate of protection. It is further unclear whether antibody levels may be used to guide the timing of booster vaccinations in older adults.METHODS We conducted a prospective multicenter cohort study comprising hospitalized patients with COVID-19. Anti–SARS-CoV-2 spike antibodies were measured on hospital admission. The primary endpoint was in-hospital mortality. Patients were stratified by age, antibody levels, and vaccination status. Multiple logistic regression and Cox regression analyses were conducted.RESULTS In total, 785 older patients (≥60 years of age [a]) and 367 controls (<60a) were included. After adjusting for confounders, risk of mortality, ICU admission, endotracheal intubation, and oxygen administration was 4.9, 2.6, 6.5, and 2.3 times higher, respectively, if antibody levels were < 1,200 BAU/mL (aOR, 4.92 [95%CI, 2.59–9.34], P < 0.0001; aOR, 2.64 [95%CI, 1.52–4.62], P = 0.0006; aOR, 6.50 [95%CI, 1.48–28.47], P = 0.013; aOR, 2.34 [95%CI, 1.60–3.343], P < 0.0001). Older adults infected with the Omicron variant were approximately 6 times more likely to die if antibody levels were < 1,200 BAU/mL (aOR, 6.3 [95% CI, 2.43–16.40], P = 0.0002).CONCLUSION Antibody levels were a stronger predictor of in-hospital mortality than vaccination status. Monitoring antibody levels may constitute a better and more direct approach for safeguarding older adults from adverse COVID-19 outcomes.
Authors
Sylvia Mink, Christoph H. Saely, Andreas Leiherer, Patrick Reimann, Matthias Frick, Janne Cadamuro, Wolfgang Hitzl, Heinz Drexel, Peter Fraunberger
Abstract
With the increasing prevalence of antimicrobial-resistant bacterial infections, there is interest in using bacteriophages (phages) to treat such infections. However, the factors that govern bacteriophage pharmacokinetics in vivo remain poorly understood. Here, we have examined the contribution of neutrophils, the most abundant phagocytes in the body, to the pharmacokinetics of i.v. administered bacteriophage in uninfected mice. A single dose of LPS-5, a bacteriophage recently used in human clinical trials to treat drug-resistant Pseudomonas aeruginosa, was administered i.v. to both immunocompetent BALB/c and neutropenic CD1 mice. Phage concentrations were assessed in peripheral blood and spleen at 0.25, 1, 2, 4, 8, 12, and 24 hours after administration by plaque assay and qPCR. We observed that the phage clearance was only minimally affected by neutropenia. Indeed, the half-lives of phages in blood in BALB/c and CD1 mice were 3.45 and 3.66 hours, respectively. These data suggest that neutrophil-mediated phagocytosis is not a major determinant of phage clearance. Conversely, we observed a substantial discrepancy in circulating phage levels over time when measured by qPCR versus plaque assay, suggesting that significant inactivation of circulating phages occurs over time. These data indicate that alternative factors, but not neutrophils, inactivate i.v. administered phages.
Authors
Arne Echterhof, Tejas Dharmaraj, Arya Khosravi, Robert McBride, Lynn Miesel, Ju-Hsin Chia, Patrick M. Blankenberg, Kun-Yuan Lin, Chien-Chang Shen, Yu-Ling Lee, Yu-Chuan Yeh, Wei Ting Liao, Francis G. Blankenberg, Krystyna Dąbrowska, Derek F. Amanatullah, Adam R. Frymoyer, Paul L. Bollyky
Abstract
Systemic sclerosis (SSc) is characterized by immune system failure, vascular insult, autoimmunity, and tissue fibrosis. Transforming growth factor-beta (TGF-β) is a crucial mediator of persistent myofibroblast activation and aberrant extracellular matrix production in SSc. The factors responsible for this are unknown. By amplifying pattern recognition receptor signaling, Triggering Receptor Expressed on Myeloid Cells 1 (TREM-1) is implicated in multiple inflammatory conditions. In this study, we used novel ligand-independent TREM-1 inhibitors in order to investigate the pathogenic role of TREM-1 in SSc, using preclinical models of fibrosis, and explanted SSc skin fibroblasts. Selective pharmacological TREM-1 blockade prevented and reversed skin fibrosis induced by bleomycin in mice and mitigated constitutive collagen synthesis and myofibroblast features in SSc fibroblasts in vitro. Our results implicate aberrantly activated TREM-1 signaling in SSc pathogenesis, identify a unique approach to TREM-1 blockade, and suggest a potential therapeutic benefit for TREM-1 inhibition.
Authors
Swarna Bale, Priyanka Verma, Bharath Yalavarthi, Matija Bajželj, Syed A.M. Hasan, Jenna N. Silverman, Katherine Broderick, Kris A. Shah, Timothy Hamill, Dinesh Khanna, Alexander B. Sigalov, Swati Bhattacharyya, John Varga
Abstract
Daptomycin is a last resort lipopeptide antibiotic that disrupts cell membrane (CM) and peptidoglycan homeostasis. Enterococcus faecalis has developed a sophisticated mechanism to avoid daptomycin killing by re-distributing CM anionic phospholipids away from the septum. The CM changes are orchestrated by a three-component regulatory system, designated LiaFSR, with a possible contribution of cardiolipin synthase (Cls). However, the mechanism by which LiaFSR controls the CM response and the role of Cls are unknown. Here, we show that cardiolipin synthase activity is essential for anionic phospholipid redistribution and daptomycin resistance since deletion of the two genes (cls1 and cls2) encoding Cls abolished CM remodeling. We identified LiaY, a transmembrane protein regulated by LiaFSR, and Cls1 as important mediators of CM remodeling required for re-distribution of anionic phospholipid microdomains. Together, our insights provide a mechanistic framework on the enterococcal response to cell envelope antibiotics that could be exploited therapeutically.
Authors
April H. Nguyen, Truc T. Tran, Diana Panesso, Kara S. Hood, Vinathi Polamraju, Rutan Zhang, Ayesha Khan, William R. Miller, Eugenia Mileykovskaya, Yousif Shamoo, Libin Xu, Heidi Vitrac, Cesar A. Arias
Abstract
BACKGROUND Congenital cytomegalovirus (cCMV) infection can cause developmental impairment and sensorineural hearing loss (SNHL). To determine the relationship between immune responses to cCMV infection and neurologic sequelae, T cell responses were compared for their connection to clinical symptoms at birth and neurodevelopmental outcomes.METHODS Thirty cCMV-infected and 15 uninfected infants were enrolled in a single-center prospective observational case-control study. T cell pp65-specific cytokine responses; CD57, CD28, and PD-1 expression; and memory subsets were compared.RESULTS Infected neonates (73% symptomatic at birth) lacked pp65-specific cytokine-secreting T cells, with elevated frequencies of CD57+, CD28–, and PD-1+CD8+ T cells and effector memory subsets. Though frequencies overlapped between cCMV symptom groups, asymptomatic infants had higher frequencies of CD57+PD-1+CD8+ T cells. Neonates with subsequent developmental delay lacked detectable CMV-specific T cell responses, with patterns resembling those of uninfected infants. Two children with progressive SNHL had high frequencies of PD-1+CD8+ T cells over the first year compared with children without progressive SNHL.CONCLUSION Similar to published reports, neonatal viral antigen–specific cytokine-secreting T cell responses were not detected, but overall patterns indicate that globally differentiated memory CD8+ T cell populations were induced by cCMV infection, with higher frequencies of terminally differentiated PD-1+CD8+ T cells potentially associated with asymptomatic infection. In this cohort, a lack of in utero T cell differentiation was associated with developmental delay, and high frequencies of PD-1+CD8+ T cells persisted only in children with progressive SNHL. Further work is needed to define the specificity of these T cells and their mechanistic connection to these outcomes.FUNDING This study was funded through an intramural research award at Nationwide Children’s Hospital, the Pediatric Infectious Disease Society Fellowship Award funded by Stanley and Susan Plotkin and Sanofi Pasteur, the Abigail Wexner Research Institute at Nationwide Children’s Hospital, and the Pichichero Family Foundation Vaccines for Children Initiative Research Award from the Pediatric Infectious Diseases Society Foundation.
Authors
Alexandra K. Medoro, Ravi Dhital, Pablo J. Sánchez, Kaitlyn Flint, Brianna Graber, Traci Pifer, Rachelle Crisan, William C. Ray, Christopher C. Phelps, Jonathan R. Honegger, Jing Peng, Ursula Findlen, Prashant Malhotra, Oliver Adunka, Masako Shimamura
Abstract
Vaginal infections in women of reproductive age represent a clinical dilemma with significant socio-economic implications. The understanding of mucosal immunity failure during early pathogenic invasions that allow the pathogen to grow and thrive is far from complete. Neutrophils infiltrate most tissues following circadian patterns as part of normal repair, regulation of microbiota, or immune surveillance and become more numerous after infection. Neutrophils are responsible for maintaining vaginal immunity. Specific to the vagina, neutrophils continuously infiltrate at high levels, although during ovulation they retreat to avoid sperm damage and permit reproduction. Here we show that after ovulation, progesterone promotes resident vaginal macrophage-neutrophils crosstalk by up-regulating Yolk sac and early fetal organs (Folr2+ (folate receptor 2)) macrophage Cxcl2 expression, in a Tnfa-monocyte-derived macrophage (Cx3cr1hi MHCIIhi) mediated manner, to activate neutrophils' capacity to eliminate sex-transmitted and opportunistic microorganisms. Indeed, progesterone plays an essential role in conciliating the balance between the commensal microbiota, sperm, and the threat of pathogens: because progesterone not only promotes a flurry of neutrophils but also increases neutrophilic fury to restore immunity after ovulation to thwart pathogenic invasion post-intercourse. Therefore, modest progesterone dysregulations could lead to a suboptimal neutrophilic response, resulting in insufficient mucosal defense and recurrent unresolved infections.
Authors
Carla Gómez-Oro, Maria C. Latorre, Patricia Arribas-Poza, Alexandra Ibáñez-Escribano, Katia R. Baca-Cornejo, Jorge Gallego-Valle, Natalia López-Escobar, Mabel Mondéjar-Palencia, Marjorie Pion, Luis A. López-Fernández, Enrique Mercader-Cidoncha, Federico Pérez-Milán, Miguel Relloso
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