Background and objective: Parapneumonic effusion (PPE) is commonly caused by Gram-positive bacteria (GPB) and often presents with pleural loculation, which is characterized by overproduction of plasminogen activator inhibitor (PAI)-1. Lipoteichoic acid (LTA), a surface adhesion molecule of GPB, binds to the pleural mesothelium and triggers inflammation. However, the effects of LTA on PAI-1 expression in PPE and underlying mechanisms remain unclear. Methods: Thirty consecutive patients with PPE were enrolled, including uncomplicated culture negative (CN, n = 11), Gram-negative bacteria (GNB, n = 7) and GPB (n = 12) groups stratified by pleural fluid characteristics and bacteriology, and the effusion PAI-1 levels were measured. In addition, human pleural mesothelial cells (PMC) were treated with LTA and the expression of PAI-1 and activation of signalling pathways were assayed. Results: The median levels of PAI-1 were significantly higher in GPB (160.5 ng/mL) and GNB (117.0 ng/mL) groups than in the uncomplicated CN (58.0 ng/mL) group. In human PMC, LTA markedly upregulated PAI-1 mRNA and protein expression and enhanced elaboration of Toll-like receptor 2 (TLR2). Furthermore, LTA increased c-Jun N-terminal kinase (JNK) phosphorylation, induced activating transcription factor 2 (ATF2)/cJun nuclear translocation and activated PAI-1 promoter activity. Pretreatment with TLR2 siRNA significantly inhibited LTA-induced JNK phosphorylation and PAI-1 protein expression. Conclusion: Culture-positive PPE, especially that caused by GPB, has a significantly higher level of PAI-1 than uncomplicated CN PPE. LTA upregulates PAI-1 expression through activation of TLR2/JNK/activator protein 1 (AP-1) pathway in human PMC. Better understanding of the modulation of PAI-1 synthesis by LTA in PPE may provide potential therapies for infected pleural effusions.

Background: The ChAdOx1 nCoV-19 vaccine has been widely administered against SARS-CoV-2 infection; however, data regarding its immunogenicity, reactogenicity, and potential differences in responses among Asian populations remain scarce. Methods: 270 participants without prior COVID-19 were enrolled to receive ChAdOx1 nCoV-19 vaccination with a prime–boost interval of 8–9 weeks. Their specific SARS-CoV-2 antibodies, neutralizing antibody titers (NT50), platelet counts, and D-dimer levels were analyzed before and after vaccination. Results: The seroconversion rates of anti-RBD and anti-spike IgG at day 28 after a boost vaccination (BD28) were 100% and 95.19%, respectively. Anti-RBD and anti-spike IgG levels were highly correlated (r = 0.7891), which were 172.9 ± 170.4 and 179.3 ± 76.88 BAU/mL at BD28, respectively. The geometric mean concentrations (GMCs) of NT50 for all participants increased to 132.9 IU/mL (95% CI 120.0–147.1) at BD28 and were highly correlated with anti-RBD and anti-spike IgG levels (r = 0.8248 and 0.7474, respectively). Body weight index was statistically significantly associated with anti-RBD IgG levels (p = 0.035), while female recipients had higher anti-spike IgG levels (p = 0.038). The GMCs of NT50 declined with age (p = 0.0163) and were significantly different across age groups (159.7 IU/mL for 20–29 years, 99.4 IU/mL for ≥50 years, p = 0.0026). Injection-site pain, fever, and fatigue were the major reactogenicity, which were more pronounced after prime vaccination and in younger participants (<50 years). Platelet counts decreased and D-dimer levels increased after vaccination but were not clinically relevant. No serious adverse events or deaths were observed. Conclusion: The vaccine is well-tolerated and elicited robust humoral immunity against SARS-CoV-2 after standard prime–boost vaccination in Taiwanese recipients.

Lupus pneumonitis carries high mortality and is a rare manifestation of systemic lupus erythematosus (SLE). However, it is difficult to diagnose and is often mistaken as pneumonia, alveolar haemorrhage, or organizing pneumonia. Previous studies demonstrated that serum anti‐Ro antibodies are elevated more frequently in SLE patients with pneumonitis than in those without. We report a 21‐year‐old female who was newly diagnosed as having SLE with nephritis and who suddenly developed right lung opacity and rapidly progressed to severe hypoxaemia despite the use of broad‐spectrum antibiotics. The serum titre of anti‐Ro antibody was greater than 240 U/mL. She underwent lung biopsy and lupus pneumonitis was confirmed by the pathological findings. Subsequently, she showed a favourable response to plasma exchange, steroid pulse therapy, and mycophenolate mofetil (MMF) treatment. For SLE patients with pulmonary infiltrates, high degree of clinical suspicion of lupus pneumonitis is required and measurement of serum anti‐Ro antibody may help to make the diagnosis.

Background and ObjectivesThe novel coronavirus disease 2019 (COVID-19) has been a pandemic health issue in 30 January 2020. The mortality rate is as high as 50% in critically ill patients. Stem cell therapy is effective for those who are refractory to standard treatments. However, the immune responses that underlie stem cell therapy have not been well reported, particularly, in patients associated with moderate to severe acute respiratory distress syndrome (ARDS).MethodsOn Days 0 and 4, an intravenous infusion of 2 × 107 placenta-derived mesenchymal stem cells (pcMSCs) (MatriPlax) were administered to five severe COVID-19 patients refractory to current standard therapies. Peripheral blood inflammatory markers and immune profiles were determined by multi-parameter flow cytometry and studied at Days 0, 4, and 8. Clinical outcomes were also observed.ResultsNone of the pc-MSC treated patients experienced 28-day mortality compared with the control group and showed a significant improvement in the PaO2/FiO2 ratio, Murray’s lung injury scores, reduction in serum ferritin, lactate dehydrogenase (LDH), and C-reactive protein (CRP) levels. The cytokine profiles also showed a reduction in IL-1β, IFN-γ, IL-2, and IL-6, and an increase in IL-13 and IL-5 type 2 cytokines within 7 days of therapy. Lymphopenia was also significantly improved after 7 days of treatment. Immune cell profiles showed an increase in the proportions of CD4+ T cells (namely, CD4+ naïve T cells and CD4+ memory T cell subtypes), Treg cells, CD19+ B cells (namely, CD19+ naïve B cells, CD27+ switched B cell subtypes) and dendritic cells, and a significant decrease in the proportion of CD14+ monocytes (namely, CD16- classical and CD16+ non-classical subtypes), and plasma/plasmablast cells. No adverse effects were seen at the serial follow-up visits for 2 months after initial therapy.Conclusionpc-MSCs therapy suppressed hyper-inflammatory states of the innate immune response to COVID-19 infection by increasing Treg cells, decreasing monocytes and plasma/plasmablast cells, and promoting CD4+ T cells and CD19+ B cells toward adaptive immune responses in severely critically ill COVID-19 patients with moderate to severe ARDS, especially those who were refractory to current standard care and immunosuppressive therapies.

Endotracheal tubes (ETTs) provide a vital connection between the ventilator and patient; however, improper placement can hinder ventilation efficiency or injure the patient. Chest X-ray (CXR) is the most common approach to confirming ETT placement; however, technicians require considerable expertise in the interpretation of CXRs, and formal reports are often delayed. In this study, we developed an artificial intelligence-based triage system to enable the automated assessment of ETT placement in CXRs. Three intensivists performed a review of 4293 CXRs obtained from 2568 ICU patients. The CXRs were labeled “CORRECT” or “INCORRECT” in accordance with ETT placement. A region of interest (ROI) was also cropped out, including the bilateral head of the clavicle, the carina, and the tip of the ETT. Transfer learning was used to train four pre-trained models (VGG16, INCEPTION_V3, RESNET, and DENSENET169) and two models developed in the current study (VGG16_Tensor Projection Layer and CNN_Tensor Projection Layer) with the aim of differentiating the placement of ETTs. Only VGG16 based on ROI images presented acceptable performance (AUROC = 92%, F1 score = 0.87). The results obtained in this study demonstrate the feasibility of using the transfer learning method in the development of AI models by which to assess the placement of ETTs in CXRs.