Background We aim to investigate the profile of acute antibody response in COVID-19 patients, and provide proposals for the usage of antibody test in clinical practice.Methods A multi-center cross-section study (285 patients) and a single-center follow-up study (63 patients) were performed to investigate the feature of acute antibody response to SARS-CoV-2. A cohort of 52 COVID-19 suspects and 64 close contacts were enrolled to evaluate the potentiality of the antibody test. ResultsThe positive rate for IgG reached 100% around 20 days after symptoms onset.The median day of seroconversion for both lgG and IgM was 13 days after symptoms onset. Seroconversion of IgM occurred at the same time, or earlier, or later than that of IgG. IgG levels in 100% patients (19/19) entered a platform within 6 days after seroconversion. The criteria of "IgG seroconversion" and "≥ 4-fold increase in the IgG titers in sequential samples" together diagnosed 82.9% (34/41) of the patients.Antibody test aided to confirm 4 patients with COVID-19 from 52 suspects who failed to be confirmed by RT-PCR and 7 patients from 148 close contacts with negative RT-PCR. ConclusionIgM and IgG should be detected simultaneously at the early phase of infection. The serological diagnosis criterion of seroconversion or the "≥ 4-fold increase in the IgG titer" is suitable for a majority of COVID-19 patients. Serologic test is helpful for the diagnosis of SARS-CoV-2 infection in suspects and close contacts.

Background COVID-19 infections are still at pandemic levels globally and there are currently no specific drugs to treat these infections. Previous studies have demonstrated that serum albumin levels were abnormally low in COVID-19 patients and might be used as a prognosis biomarker. Supplemental albumin has been used as an experimental therapeutic method. However, dynamic evaluation of albumin in patients with COVID-19 was limited and whether serum albumin could predict the prognosis of these patients is unknown. Methods We enrolled 79 COVID-19 patients in the present study and reviewed electronic medical laboratory records. Data was processed using SPSS software (Version 20.0) and correlation analysis was performed between serum albumin and other clinical and laboratory findings. Results Serum albumin levels were gradually decreased both in severe and non-severe COVID-19 patients. Moreover, 17.7% of the patients presented with hypoalbuminemia at least one time during 3 consecutive weekly time points. The hypoalbuminemia group displayed more severe disease and comorbidity that included fever, fatigue, headache, and dizziness on admission. Moreover, serum albumin levels were positively correlated with lymphocyte and RBC numbers, Hb and prealbumin levels as well as with total T cell numbers and the presence of CD4 + and CD8 + T cells. In contrast, there was a negative correlation with C-reactive protein levels and this was an indicator of patient recovery. Conclusion Our results demonstrated that hypoalbuminemia was common in COVID-19 patients and its levels were linked to disease severity. Patients with fever, fatigue and headache or dizziness on admission were more likely to experience hypoalbuminemia. Dynamic monitoring of serum albumin is therefore necessary and should be performed during COVID-19 patient treatments as a tool for evaluating the prognosis of COVID-19 infections.

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Sex-determining region Y-box 2 (SOX2), as a subunit of transcription and reprogramming factor, plays a critical role in the development and progression of many malignancies, including lung cancer through gene amplification. In the present study, we aimed to quantify the levels of serum SOX2 DNA, analyze its diagnostic value and compare it with existing clinical parameters in lung cancer, and purpose to provide a novel tumor marker for lung cancer. Serum DNA was extracted from 94 lung cancer patients, 10 benign lung diseases, and 30 healthy volunteers, and then the levels of SOX2 DNA were quantified using real-time fluorescent quantitative polymerase chain reaction (FQ-PCR). The data were analyzed by statistical software SPSS14.0. The present results show that serum SOX2 DNA level in lung cancer group was higher compared to the levels in benign lung diseases group (u = 102.0, p < 0.001) or healthy group (u = 140.0, p < 0.001), and it was closely associated with TNM stage, histopathological type, and tumor size (p = 0.031, p = 0.012, and p = 0.010, respectively). However, serum SOX2 DNA levels of lung cancer patients were not associated with age, gender, smoking status, lymph node metastasis, or tumor differentiation (p > 0.05). ROC curve showed a sensitivity of 78.9% and a specificity of 82.5% for the ability of serum SOX2 DNA to detect lung cancer at the cutoff value of 1,078.3 copies/ul. Furthermore, we assessed the associations of serum SOX2 levels with clinical existing lung tumor markers, such as squamous cell carcinoma antigen, cytokeratin fragment 21-1, and neuron-specific enolase. The sensitivity was increased from 24.9, 66.1, and 39.1 to 84.2, 92.8, and 87.5%, respectively, by the combination of serum SOX2 DNA. Taken together, quantification of serum SOX2 DNA by FQ-PCR may serve as a novel accessory diagnostic tool for the clinical screening and detection of lung cancer.

Considerable research has been devoted to unraveling the regulation of neural stem cell (NSC) differentiation. The responses of NSCs to various differentiation-inducing stimuli, however, are still difficult to estimate. In this study, we aimed to search for a potent growth factor that was able to effectively induce differentiation of NSCs toward Schwann cells. NSCs were isolated from dorsal root ganglia (DRGs) of adult rats and identified by immunostaining. Three different growth factors were used to stimulate the differentiation of DRG-derived NSCs (DRG-NSCs). We found that among these three growth factors, bFGF was the strongest inducer for the glial differentiation of DRG-NSCs, and bFGF induced the generation of an increased number of Schwann cell-like cells as compared to nerve growth factor (NGF) and neuregulin1-β (NRG). These Schwann cell-like cells demonstrated the same characteristics as those of primary Schwann cells. Furthermore, we noted that bFGF-induced differentiation of DRG-NSCs toward Schwann cells might be mediated by binding to fibroblast growth factor receptor-1 (FGFR-1) through activation of MAPK/ERK signal pathway.