Longitudinal single-cell immune profiling revealed distinct innate immune response in asymptomatic COVID-19 patients

Recent studies have characterized the single-cell immune landscape of host immune response of coronavirus disease 2019 (COVID-19), specifically focus on the severe condition. However, the immune response in mild or even asymptomatic patients remains unclear. Here, we performed longitudinal single-cell transcriptome sequencing and T cell/B cell receptor sequencing on 3 healthy donors and 10 COVID-19 patients with asymptomatic, moderate, and severe conditions. We found asymptomatic patients displayed distinct innate immune responses, including increased CD56briCD16- NK subset, which was nearly missing in severe condition and enrichment of a new Th2-like cell type/state expressing a ciliated cell marker. Unlike that in moderate condition, asymptomatic patients lacked clonal expansion of effector CD8+ T cells but had a robust effector CD4+ T cell clonal expansion, coincide with previously detected SARS-CoV-2-reactive CD4+ T cells in unexposed individuals. Moreover, NK and effector T cells in asymptomatic patients have upregulated cytokine related genes, such as IFNG and XCL2. Our data suggest early innate immune response and type I immunity may contribute to the asymptomatic phenotype in COVID-19 disease, which could in turn deepen our understanding of severe COVID-19 and guide early prediction and therapeutics.

Role of GFRα3 in expression and membrane trafficking of TRPM8 in dorsal root ganglion during cold hyperalgesia in rats with neuropathic pain / 中华麻醉学杂志

Objective To evaluate the role of glial cell line-derived neurotrophic factor family re-ceptor alpha3(GFRα3)in the expression and membrane trafficking of transient receptor potential melasta-tin 8(TRPM8)in the dorsal root ganglion(DRG)during cold hyperalgesia in rats with neuropathic pain (NP). Methods Thirty-two healthy adult male Sprague-Dawley rats, aged 10-12 weeks, weighing 250-280 g, in which intrathecal catheters were successfully implanted, were divided into 4 groups(n=8 each) using a random number table: sham operation plus GFRα3 dsRNA group(Sham+dsRNA group), sham operation plus GFRα3 siRNA group(group Sham+siRNA), NP plus GFRα3 dsRNA group(group NP+dsRNA)and NP plus GFRα3 siRNA group(group NP+siRNA). NP was produced by chronic constriction injury to the sciatic nerve. At 10-30 days after operation, GFRα3 dsRNA 10 μg∕20 μl was intrathecally injected once a day for 4 consecutive days in Sham+dsRNA and NP+dsRNA groups, and 10 μg∕20 μl GFRα3 siRNA, of which the sense strand was modified with 2′-O-methyl and 5′-cholesterol, was intrathe-cally injected once a day for 4 consecutive days in Sham+siRNA and NP+siRNA groups. The number of paw lifts on the cold plate, mechanical paw withdrawal threshold(MWT)and thermal paw withdrawal latency (TWL)were measured on 1 day before operation and 10, 11, 12, 13(before intrathecal injection)and 14 days after operation. The rats were sacrificed after the last behavioral testing, and ipsilateral DRGs of the lumbar segment(L4-6)were dissected for detection of the expression of GFRα3 and TRPM8 in total and membrane proteins by Western blot, and the ratio of TRPM8 expression in the membrane protein to that in the total protein(m∕t ratio)was calculated. Results Compared with group Sham+dsRNA, the number of paw lifts on the cold plate was significantly increased, the MWT was decreased, and TWL was shortened after operation in NP+dsRNA and NP+siRNA groups, the expression of GFRα3 and TRPM8 in total and membrane proteins was significantly up-regulated, and m∕t ratio was increased in group NP+dsRNA, and the expression of GFRα3 in DRGs was significantly down-regulated(P<001), and no significant change was found in the expression of TRPM8 in total and membrane proteins or m∕t ratio in group NP+siRNA(P>005). Compared with group NP+dsRNA, the number of paw lifts on the cold plate was significantly de-creased, the expression of GFRα3 and TRPM8 in total and membrane proteins was down-regulated, m∕t ra-tio was decreased(P<001), and no significant change was found in MWT or TWL in group NP+siRNA (P>005). Conclusion GFRα3 in DRGs can up-regulate the expression of TRPM8 and enhance the membrane trafficking of TRPM8, which may be involved in the maintenance mechanism of cold hyperalgesia in rats with NP.

Effects of hydrogen gas inhalation on serum high mobility group box 1 levels in severe septic mice / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate the effect of hydrogen gas inhalation on survival rate and serum high mobility group box 1 (HMGB1) levels in severe septic mice.</p><p><b>METHODS</b>Severe sepsis was induced by cecal ligation and puncture (CLP) operation in mice.A total of 248 mice were randomly divided into four groups: sham operation group (sham), sham operation with hydrogen gas inhalation group (sham+H2), severe CLP group (severe CLP) and severe CLP with hydrogen gas inhalation group (severe CLP+H2). Hydrogen gas inhalation was given for 1 h at 1st and 6th h after CLP or sham operation, respectively. The survival rates and serum HMGB1 levels of all groups at different time points were measured.</p><p><b>RESULT</b>The 7-d survival rates of severe CLP mice was 0 % (Compared with Sham group, P <0.05), and the serum HMBG1 levels from h2 to h32 after CLP operation were significantly increased in severe CLP mice (Compared with Sham group, P <0.05). Hydrogen gas treatment increased the 7-d survival rate of severe CLP mice to 60 % (Compared with severe sepsis group, P <0.05) and significantly reduced the serum HMGB1 levels at different time points (Compared with severe sepsis group, P <0.05).</p><p><b>CONCLUSION</b>Hydrogen gas inhalation can decrease the serum HMGB1 levels and increase the survival rate of rats with severe sepsis.</p>

Value of 18F-FDG-PET/CT in diagnosis of classic fever of unknown origin / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To evaluate the application of (18)F-FDG PET/CT in diagnosis of classic fever of unknown origin.</p><p><b>METHODS</b>A total of 27 consecutive patients with classic fever of unknown origin (FUO) (19 men, 8 women; aged 24-82 y) underwent (18)F-FDG PET/CT scans. The images were interpreted by visual inspection and semiquantitative analysis(standardized uptake value, SUV). Final diagnosis was based on histopathology or clinical follow-up.</p><p><b>RESULTS</b>The cause of FUO was confirmed by followed investigations in 21 of 27 cases after PET/CT scan, including 10 cases of infection, 4 of noninfectious inflammation, 4 of malignancies and 3 of miscellaneous disorders; and remaining 6 cases were still confirmed FUO. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy were 100.0 %, 83.3%, 83.3%, 100.0% and 96.3%, respectively.</p><p><b>CONCLUSION</b>For patients with fever of unknown origin, (18)F-FDG-PET/CT can be a sensitive, reliable imaging modality. It is suggested that (18)F-FDG-PET/CT should be considered earlier in detecting the causes of FUO, which is difficultly diagnosed by conventional modalities.</p>

Monocyte response and regulatory effect of emodin and shenmai injection on it in patients with severe sepsis / 中国中西医结合杂志

<p><b>OBJECTIVE</b>To investigate the impact of monocyte releasing tumor necrosis factor-alpha (TNF-alpha) and interleukin-10 (IL-10) stimulated by lipopolysaccharide (LPS) in severe sepsis (SS) patients, and the regulatory effect of emodin and Shenmai Injection (SMI) on monocyte response.</p><p><b>METHODS</b>ocyte (PBMC) sampled from SS patients due to severe abdominal inflammation and healthy controls, PBMC were incubated with or without LPS, respectively. PBMC media pretreated with emodin and SMI, and then the levels of cytokine factors including TNF-alpha and IL-10 in supernatants were determined after stimulated with or without LPS in the two groups. Normal PBMC stimulated with LPS based on incubated with either normal serum or SS serum, and the levels of TNF-alpha and IL-10 in supernatant of normal PBMC and SS serum dealing with emodin or SMI after cultured and stimulated with LPS were determined, respectively.</p><p><b>RESULTS</b>The levels of TNF-alpha and IL-10 were significantly higher in SS patients than those in the healthy adults. The contents of TNF-alpha and IL-10 increased in response to LPS in PBMC of healthy adults, and the excretion of TNF-alpha was significantly attenuated whereas IL-10 significantly increased in septic PBMC than basal content. Both of the two traditional Chinese medicines had significantly effect in stimulating PBMC secretion in healthy adults and SS patients. In normal PBMC, emodin attenuated TNF-alpha and IL-10 release in response to LPS, and SMI significantly inhibited TNF-alpha release. As to septic PBMC, emodin significantly stimulated TNF-alpha and IL-10 release and SMI significantly increased the concentration of TNF-alpha in the SS patients. Incubation of normal PBMC with septic serum attenuated TNF-alpha production, whereas increased IL-10 release. Emodin could significantly decrease the level of IL-10, and SMI recovered TNF-alphareleasing and had no effect on IL-10.</p><p><b>CONCLUSION</b>The level of TNF-alpha significantly decreased accompanied with an anti-inflammatory cytokine IL-10 significantly increased of PBMC in SS patients. Monocyte exhibits the different response of inflammatory or anti-inflammatory factor which may be one of the reasons of imbalance of immune function in SS patients. Both of emodin and SMI may have regulatory effect on excretion of PBMC in SS patients, but they play a role in different ways.</p>