A follow-up study on the recovery and reinfection of Omicron COVID-19 patients in Shanghai, China.

Limited follow-up data is available on the recovery of Omicron COVID-19 patients after acute illness. It is also critical to understand persistence of neutralizing antibody (NAb) and of T-cell mediated immunity and the role of hybrid immunity in preventing SARS-CoV-2 reinfection. This prospective cohort study included Omicron COVID-19 individuals from April to June 2022 in Shanghai, China, during a large epidemic caused by the Omicron BA.2 variant. A total of 8945 patients from three medical centres were included in the follow up programme from November 2022 to February 2023. Of 6412 individuals enrolled for the long COVID analysis, 605 (9.4%) individuals experienced at least one sequelae, mainly had fatigue and mental symptoms specific to Omicron BA.2 infection compared with other common respiratory tract infections. During the second-visit, 548 (12.1%) cases of Omicron reinfection were identified. Hybrid immunity with full and booster vaccination had reduced risk of SARS-CoV-2 reinfection by 0.29-fold (95% CI: 0.63-0.81) and 0.23-fold (95% CI: 0.68-0.87), respectively. For 469 participants willing to the hospital during the first visit, those who received full (72 [IQR, 36-156]) or booster (64 [IQR, 28-132]) vaccination had significantly higher neutralizing antibody titers than those with incomplete vaccination (36 [IQR, 16-79]). Moreover, non-reinfection cases had higher neutralizing antibody titers (64 [IQR, 28-152]) compared to reinfection cases (32 [IQR, 20-69]).

Understanding the viral shedding time of Omicron variant BA.2 infection in Shanghai: A population-based observational study.

Objectives: To explore the multifactorial causality of prolonged viral shedding time and identify different viral shedding trajectories in Omicron BA.2 variant infections. Methods: The Kaplan-Meier method was used to estimate the survivor function, and the Cox proportional hazards model was fitted to identify factors associated with viral shedding time. Group-based trajectory model (GBTM) was used to identify different viral shedding trajectories. Ordinal logistic regression was used to identify factors that significantly impacted the trajectory membership. Results: The overall median viral shedding time was 12 days (interquartile range [IQR]: 8-15). Viral shedding time was longer for female cases, cases who were incompletely vaccinated, cases with comorbidities, cases with severe or critical infections and cases who had not taken Paxlovid within 5 days after diagnosis. Compared to the 3 to 17-year-old group, all older groups had significantly longer viral shedding times. The GBTMs based on the N gene and the ORF1ab gene were consistent. Three viral shedding trajectories were identified and age group, comorbidities, vaccination status, disease state, Paxlovid treatment were significantly associated with the trajectory membership. Conclusion: Increased age, comorbidities, incomplete vaccination, severe or critical infections, and delayed Paxlovid treatment were the risk factors for prolonged viral shedding time.

GLOBAL SIGNATURES OF THE MICROBIOME AND METABOLOME DURING HOSPITALIZATION OF SEPTIC PATIENTS.

ABSTRACT: Background: The gut plays an important role in the development of sepsis and acts as one of the possible drivers of multiple-organ dysfunction syndrome. This study aimed to explore the dynamic alterations in the gut microbiota and its metabolites in septic patients at different stages of intensive care unit (ICU) admission. Methods: In this prospective observational study, a total of 109 fecal samples from 23 septic patients, 16 nonseptic ICU patients and 10 healthy controls were analyzed. 16S rRNA gene sequencing and ultra-performance liquid chromatography coupled to tandem mass spectrometry targeted metabolomics were used for microbiota and metabolome analysis. A prediction model combining the Sequential Organ Failure Assessment score, Klebsiella , taurocholic acid, and butyric acid was used to predict the prognosis of sepsis. Results: The diversity and dominant species of the gut microbiota of septic patients were significantly disturbed. The proportions of normal gut microbiota, such as Firmicutes on the phylum level, as well as Faecalibacterium, Subdoligranulum , Ruminococcus , Agathobacter , and Blautia on the genus level, were decreased at different stages of ICU admission, while the proportions of potential pathogenic bacteria, such as Proteobacteria on the phylum level, and Enterococcus and Stenotrophomonas on the genus level were significantly increased. In addition, the amount of short-chain fatty acids and secondary bile acids decreased in septic patients, while that of the primary bile acids increased markedly. Bacterial richness and diversity were lower in the nonsurviving patients than those in the surviving patients in the later stage of ICU admission. In the nomogram model, the higher abundance of Klebsiella , concentration of taurocholic acid, and Sequential Organ Failure Assessment score, combined with a lower butyric acid concentration, could predict a higher probability of death from sepsis. Conclusions: Our study indicated that the dynamical alterations of gut microbiota and its metabolites were associated with the prognosis of the sepsis. Based on these alterations and clinical indicators, a nomogram model to predict the prognosis of septic patients was performed.

Gpr174 Knockout Alleviates DSS-Induced Colitis via Regulating the Immune Function of Dendritic Cells.

Background: Dysfunction of the immune system would disturb the intestinal homeostasis and lead to inflammatory bowel disease (IBD). Dendritic cells (DCs) help maintain intestinal homeostasis and immediately respond to pathogens or injuries once the mucosa barriers are destroyed during IBD. G protein-coupled receptors(GPR)174 is an essential regulator of immunity that is widely expressed in most immune cells, including DCs. However, the role of GPR174 in regulating the immune function of DC in colitis has not been investigated. Methods: Dextran sodium sulfate (DSS) was administered to establish the mice colitis model. Data of weight, length of colon, disease activity index (DAI), and macroscopic scores were collected. The flow cytometry was used to detect the infiltrations of T cells and DCs, the mean fluorescence intensity (MFI) of CD80, CD86, CD40, and major histocompatibility complex-II (MHC-II). And T cells proliferataion was measured by carboxyfluorescein diacetate succinimidyl ester (CFSE). The expression of cytokines (tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), interleukin-10 (IL-10), interferon-γ (IFN-γ), interleukin -4 (IL-4)) and GPR174 mRNA were measured by Elisa, quantitative polymerase chain reaction (qPCR), and immunofluorescence. RNA of bone-marrow-derived dendritic cells (BMDCs) was extracted for sequencing. Adoptive transfer of BMDCs was administrated intravenously. Results: Gpr174-/- mice exposed to 3% DSS showed significant alleviation characterized by reduced loss of weight, more minor colon damage, and better DAI and macroscopic scores. The expression of pro-inflammatory cytokines (TNF-α, IL-6) decreased, while anti-inflammatory cytokine (IL-10) increased compared with WT mice. In vitro, Gpr174-/- BMDCs showed less maturity, with a declined expression of MHC-II, CD80, CD86 and reduced TNF-α, higher IL-10 after LPS stimulation. Gpr174-/- BMDCs were less capable of activating OT-II naïve CD4+ T cells than WT BMDCs and induced more Th0 cells to differentiate into Treg while less into Th1. Furthermore, the transcriptome sequencing analysis exhibited that Gpr174 participated in TNF-α (NF-κB) signaling, leukocyte transendothelial migration, and Th1/Th2 cell differentiation pathways. Adoptive transfer of Gpr174-/- BMDCs to WT mice ameliorated DSS-induced colitis. Conclusion: Our study indicated that GPR174 was involved in the pathogenesis of IBD by regulating the maturation of the dendritic cells to maintain immune homeostasis. TNF-α (NF-κB) signaling pathway, leukocyte transendothelial migration, and Th1/Th2 cell differentiation pathways may be the target pathway.

The pathogens of secondary infection in septic patients share a similar genotype to those that predominate in the gut.

BACKGROUND: Secondary nosocomial infections, which are commonly caused by carbapenem-resistant Klebsiella pneumoniae (CRKP) and vancomycin-resistant Enterococcus faecium (VRE), often develop in septic patients. This study aimed to identify the origin of secondary systemic pathogens and reveal the underlying mechanism of infection. METHODS: In this prospective, observational case-control study, a total of 34 septic patients, 33 non-septic intensive care unit (ICU) patients and 10 healthy individuals serving as controls were enrolled. Three hundred and twelve fecal samples were collected and subjected to 16S rRNA gene amplicon sequencing. Metagenome sequencing was performed to identify the homology between dominant CRKP or VRE in the intestine and pathogens isolated from secondary infectious sites. C57/BL mice were established as pseudo germ-free animal model by pretreatment with broad-spectrum antibiotics for two weeks. RESULTS: The abundance and diversity of the gut microbiota in septic patients was drastically decreased one week after ICU admission, potentially leading to the enrichment of antibiotic-resistant bacteria, such as CRKP. Furthermore, secondary bloodstream and abdominal infections caused by CRKP or VRE in septic patients occurred after intestinal colonization with the predominant bacterial species. Genomic analysis showed that bacteria isolated from secondary infection had high homology with the corresponding predominant intestinal opportunistic pathogens. In addition, animal model experiments validated the hypothesis that the administration of antibiotics caused the enrichment of CRKP and VRE among the intestinal microbiota, increasing the likelihood of permeation of other tissues and potentially causing subsequent systemic infection in pseudo germ-free mice. CONCLUSION: Our study indicated that the pathogens causing secondary infection in septic patients might originate from the intestinal colonization of pathogens following broad-spectrum antibiotic treatment.

Protective role of (5R)-5-hydroxytriptolide in lipopolysaccharide-induced acute lung injury by suppressing dendritic cell activation.

(5R)-5-hydroxytriptolide (LLDT-8) is a triptolide derivative with potent immunosuppressive property. This study aimed to investigate whether LLDT-8 manifests anti-inflammatory effects and influences dendritic cell function in early phase of lipopolysaccharide (LPS)-induced acute lung injury (ALI). C57BL/6 mice were administrated with LPS (6 mg/kg) to induce ALI and LLDT-8 were administrated at different doses (0.125 mg, 0.25 mg, 0.5 mg/kg). Histological changes were demonstrated by hematoxylin and eosin staining. Activation of dendritic cells were measured by flow cytometry. The concentrations of cytokines were measured by enzyme-linked immunosorbent assay. Bone marrow-derived dendritic cells (BMDCs) were acquired to explore immunosuppressive effects of LLDT-8 in vitro. Expression of Toll-like receptor 4 (TLR4), phosphorylation of inhibitor kappa B alpha (IκBα) and nuclear translocation of nuclear factor kappa B (NF-κB) were explored by immunoblot. Immunosuppressive property of LLDT-8-treated BMDCs were measured by adoptive transfer. The survival rate of ALI mice was significantly improved by LLDT-8 at the dose of 0.25 mg/kg. Moreover, systemic inflammatory response was suppressed and lung injury was relieved. LLDT-8 inhibited the activation of dendritic cells in vivo and influenced maturation, apoptosis and cytokine secretion capacity of BMDCs in vitro. Additionally, LLDT-8-treated BMDCs manifested reduced expression of TLR4, phosphorylation of IκBα and nuclear translocation of NF-κB. Adoptive transfer of LLDT-8-treated BMDCs alleviated LPS-induced lung injury. LLDT-8 also had protective effects on Pseudomonas aeruginosa-induced ALI. In conclusion, LLDT-8 played a protective role against ALI and suppressed dendritic cell activation potentially through affecting TLR4 expression and NF-κB signaling.

Identification of soluble thrombomodulin and tissue plasminogen activator-inhibitor complex as biomarkers for prognosis and early evaluation of septic shock and sepsis-induced disseminated intravascular coagulation.

BACKGROUND: Endothelium injury and coagulation dysfunction play an important role in the pathogenesis of sepsis. Soluble thrombomodulin (sTM), tissue plasminogen activator-inhibitor complex (t-PAIC), thrombin-antithrombin complex (TAT) and α2-plasmin inhibitor-plasmin complex (PIC) are biomarkers of endothelium injury and coagulation dysfunction. This study aimed to explore the prognostic values and diagnostic performance for septic shock and sepsis-induced disseminated intravascular coagulation (DIC) of endothelial biomarkers. METHODS: We conducted an observational study on patients with sepsis admitted to intensive care unit (ICU) at a teaching hospital from January 2016 to December 2018. Levels of sTM, t-PAIC, TAT and PIC were measured at admission day and day 5-7 after admission and detected by qualitative chemiluminescence enzyme immunoassay performed on HISCL automated analyzers. RESULTS: A total of 179 septic patients and 125 non-septic ICU controls were enrolled. The level of sTM was higher in septic patients compared to ICU controls (OR =1.093, 95% CI: 1.045-1.151, P<0.001). Moreover, higher levels of sTM and t-PAIC were independent predictors of poor 60-day prognosis for septic patients (HR =1.012, 95% CI: 1.003-1.022, P=0.012; HR =1.014, P=0.009). Level of sTM was also higher in patients with septic shock as revealed by multivariate analysis (OR =1.049, 95% CI: 1.020-1.078, P=0.001), as well as in patients with sepsis-induced DIC (OR =1.109, 95% CI: 1.065-1.158, P<0.001). sTM was considered as a sensitive biomarker for the early prediction of septic shock and sepsis-induced DIC, with AUC up to 0.765 (0.687-0.842) and 0.864 (0.794-0.935) of receiver operating characteristic curve. CONCLUSIONS: Most patients developed coagulopathy which was closely linked to endothelial injury in initial phase of sepsis, which was demonstrated by abnormalities in endothelial biomarkers and their strong association with poor 60-day prognosis and development of septic shock and sepsis-induced DIC.

Prognosis-related classification and dynamic monitoring of immune status in patients with sepsis: A prospective observational study.

BACKGROUND: The dynamic monitoring of immune status is crucial to the precise and individualized treatment of sepsis. In this study, we aim to introduce a model to describe and monitor the immune status of sepsis and to explore its prognostic value. METHODS: A prospective observational study was carried out in Zhongshan Hospital, Fudan University, enrolling septic patients admitted between July 2016 and December 2018. Blood samples were collected at days 1 and 3. Serum cytokine levels (e.g., tumor necrosis factor-α [TNF-α], interleukin-10 [IL-10]) and CD14+ monocyte human leukocyte antigen-D-related (HLA-DR) expression were measured to serve as immune markers. Classification of each immune status, namely systemic inflammatory response syndrome (SIRS), compensatory anti-inflammatory response syndrome (CARS), and mixed antagonistic response syndrome (MARS), was defined based on levels of immune markers. Changes of immune status were classified into four groups which were stabilization (SB), deterioration (DT), remission (RM), and non-remission (NR). RESULTS: A total of 174 septic patients were enrolled including 50 non-survivors. Multivariate analysis discovered that IL-10 and HLA-DR expression levels at day 3 were independent prognostic factors. Patients with MARS had the highest mortality rate. Immune status of 46.1% patients changed from day 1 to day 3. Among four groups of immune status changes, DT had the highest mortality rate, followed by NR, RM, and SB with mortality rates of 64.7%, 42.9%, and 11.2%, respectively. CONCLUSIONS: Severe immune disorder defined as MARS or deterioration of immune status defined as DT lead to the worst outcomes. The preliminary model of the classification and dynamic monitoring of immune status based on immune markers has prognostic values and is worthy of further investigation.

GPR174 mRNA Acts as a Novel Prognostic Biomarker for Patients With Sepsis via Regulating the Inflammatory Response.

Previous studies indicated that G-protein coupled receptor 174 (GPR174) is involved in the dysregulated immune response of sepsis, however, the clinical value and effects of GPR174 in septic patients are still unknown. This study is aimed to evaluate the potential value of GPR174 as a prognostic biomarker for sepsis and explore the pathological function of GPR174 in cecal ligation and puncture (CLP)-induced septic mice. In this prospective longitudinal study, the expressions of peripheral GPR174 mRNA were measured in 101 septic patients, 104 non-septic ICU controls, and 46 healthy volunteers at Day 1, 7 after ICU (Intensive Care Unit) admission, respectively. Then, the clinical values of GPR174 for the diagnosis, severity assessment, and prognosis of sepsis were analyzed. Moreover, the expressions of GPR174 mRNA in CLP-induced septic mice were detected, and Gpr174-knockout (KO) mice were used to explore its effects on inflammation. The results showed that the levels of GPR174 mRNA were significantly decreased in septic patients compared with non-septic ICU and healthy controls. In addition, the expressions of GPR174 mRNA were correlated with the lymphocyte (Lym) counts, C-reactive protein (CRP), and APACHE II and SOFA scores. The levels of GPR174 mRNA at Day 7 had a high AUC in predicting the death of sepsis (0.83). Further, we divided the septic patients into the higher and lower GPR174 mRNA expression groups by the ROC cut-off point, and the lower group was significantly associated with poor survival rate (P = 0.00139). Similarly, the expressions of peripheral Gpr174 mRNA in CLP-induced septic mice were also significantly decreased, and recovered after 72 h. Intriguingly, Gpr174-deficient could successfully improve the outcome with less multi-organ damage, which was mainly due to an increased level of IL-10, and decreased levels of IL-1ß and TNF-α. Further, RNA-seq showed that Gpr174 deficiency significantly induced a phenotypic shift toward multiple immune response pathways in septic mice. In summary, our results indicated that the expressions of GPR174 mRNA were associated with the severity of sepsis, suggesting that GPR174 could be a potential prognosis biomarker for sepsis. In addition, GPR174 plays an important role in the development of sepsis by regulating the inflammatory response.

Clinical characteristics and prognosis of community-acquired pneumonia in autoimmune disease-induced immunocompromised host: A retrospective observational study.

BACKGROUND: Community-acquired pneumonia (CAP) in autoimmune diseases (AID)-induced immunocompromised host (ICH) had a high incidence and poor prognosis. However, only a few studies had determined the clinical characteristics of these patients. Our study was to explore the characteristics and predictors of mortality in CAP patients accompanied with AID-induced ICH. METHODS: From 2013 to 2018, a total of 94 CAP patients accompanied with AID-induced ICH, admitted to Emergency Department of Zhongshan Hospital, Fudan University, were enrolled in this study. Clinical data and the risk regression estimates of repeated predictors were evaluated by generalized estimating equations (GEEs) analysis. An open-cohort approach was used to classify patient's outcomes into the survival or non-survival group. RESULTS: The hospital mortality of patients with CAP occurring in AID-induced ICH was 60.64%. No significant differences were found with respect to clinical symptoms and lung images between survival and non-survival groups, while renal insufficiency and dysfunction of coagulation had higher proportions in non-survival patients (P<0.05). Both noninvasive ventilation (NIV) and invasive mechanical ventilation (IMV) were performed more frequently in non-survival group (P< 0.05). By the multivariate GEEs analysis, the repeated measured longitudinal indices of neutrophil-to-lymphocyte ratio (NLR) (odds ratio [OR]=1.055, 95% confidence interval [95%CI] 1.025-1.086), lactate dehydrogenase (LDH) (OR=1.004, 95%CI 1.002-1.006) and serum creatinine (sCr) (OR=1.018, 95%CI 1.008-1.028), were associated with a higher risk of mortality. CONCLUSION: The CAP patients in AID-induced ICH had a high mortality. A significant relationship was demonstrated between the factors of NLR, LDH, sCr and mortality risk in these patients.

p53 regulates ERK1/2/CREB cascade via a novel SASH1/MAP2K2 crosstalk to induce hyperpigmentation.

We previously reported that three point mutations in SASH1 and mutated SASH1 promote melanocyte migration in dyschromatosis universalis hereditaria (DUH) and a novel p53/POMC/Gαs/SASH1 autoregulatory positive feedback loop is regulated by SASH1 mutations to induce pathological hyperpigmentation phenotype. However, the underlying mechanism of molecular regulation to cause this hyperpigmentation disorder still remains unclear. In this study, we aimed to investigate the molecular mechanism undergirding hyperpigmentation in the dyschromatosis disorder. Our results revealed that SASH1 binds with MAP2K2 and is induced by p53-POMC-MC1R signal cascade to enhance the phosphorylation level of ERK1/2 and CREB. Moreover, increase in phosphorylated ERK1/2 and CREB levels and melanogenesis-specific molecules is induced by mutated SASH1 alleles. Together, our results suggest that a novel SASH1/MAP2K2 crosstalk connects ERK1/2/CREB cascade with p53-POMC-MC1R cascade to cause hyperpigmentation phenotype of DUH.

A novel P53/POMC/Gαs/SASH1 autoregulatory feedback loop activates mutated SASH1 to cause pathologic hyperpigmentation.

p53-Transcriptional-regulated proteins interact with a large number of other signal transduction pathways in the cell, and a number of positive and negative autoregulatory feedback loops act upon the p53 response. P53 directly controls the POMC/α-MSH productions induced by ultraviolet (UV) and is associated with UV-independent pathological pigmentation. When identifying the causative gene of dyschromatosis universalis hereditaria (DUH), we found three mutations encoding amino acid substitutions in the gene SAM and SH3 domain containing 1 (SASH1), and SASH1 was associated with guanine nucleotide-binding protein subunit-alpha isoforms short (Gαs). However, the pathological gene and pathological mechanism of DUH remain unknown for about 90 years. We demonstrate that SASH1 is physiologically induced by p53 upon UV stimulation and SASH and p53 is reciprocally induced at physiological and pathophysiological conditions. SASH1 is regulated by a novel p53/POMC/α-MSH/Gαs/SASH1 cascade to mediate melanogenesis. A novel p53/POMC/Gαs/SASH1 autoregulatory positive feedback loop is regulated by SASH1 mutations to induce pathological hyperpigmentation phenotype. Our study demonstrates that a novel p53/POMC/Gαs/SASH1 autoregulatory positive feedback loop is regulated by SASH1 mutations to induce pathological hyperpigmentation phenotype.