ABSTRACT
BackgroundSARS-CoV-2-caused coronavirus disease (COVID-19) is posing a large casualty. The features of COVID-19 patients with and without pneumonia, SARS-CoV-2 transmissibility in asymptomatic carriers, and factors predicting disease progression remain unknown. MethodsWe collected information on clinical characteristics, exposure history, and laboratory examinations of all laboratory-confirmed COVID-19 patients admitted to PLA General Hospital. Cox regression analysis was applied to identify prognostic factors. The last follow-up was February 18, 2020. ResultsWe characterized 55 consecutive COVID-19 patients. The mean incubation was 8.42 (95% confidence interval [CI], 6.55-10.29) days. The mean SARS-CoV-2-positive duration from first positive test to conversion was 9.71 (95%CI, 8.21-11.22) days. COVID-19 course was approximately 2 weeks. Asymptomatic carriers might transmit SARS-CoV-2. Compared to patients without pneumonia, those with pneumonia were 15 years older and had a higher rate of hypertension, higher frequencies of having a fever and cough, and higher levels of interleukin-6 (14.61 vs. 8.06pg/mL, P=0.040), B lymphocyte proportion (13.0% vs.10.0%, P=0.024), low account (<190/{micro}L) of CD8+ T cells (33.3% vs. 0, P=0.019). Multivariate Cox regression analysis indicated that circulating interleukin-6 and lactate independently predicted COVID-19 progression, with a hazard ratio (95%CI) of 1.052 (1.000-1.107) and 1.082 (1.013-1.155), respectively. During disease course, T lymphocytes were generally lower, neutrophils higher, in pneumonia patients than in pneumonia-free patients. CD8+ lymphocytes did not increase at the 20th days after illness onset. ConclusionThe epidemiological features are important for COVID-19 prophylaxis. Circulating interleukin-6 and lactate are independent prognostic factors. CD8+ T cell exhaustion might be critical in the development of COVID-19.
ABSTRACT
Objective To improve the purifying method of Jo-1 antigen from rabbit thymus used for detection of anti-Jo-1 antibody by dot-blotting immunoassay(DB).Methods The rabbit thymus glands were cut into pieces,homogenized and extracted by PBS.Total protein was precipitated by acetone to get acetone powder(RTAP).The RTAP was solved in PBS and separated by an by anti-Jo-1 IgG affinity column.Results 5～7 g RTAP was obtained from 100g rabbit thymus glands.There was 19%～24% of protein in RTAP.Jo-1 antigen was enriched around 1900 folds through affinity chromatography,with 2.5% recovery of antigenic activity.In this preparation,there were several bands on SDS-PAGE,but only one band about 50 ku,reacted with anti-Jo-1 antisera on immunoblotting.Dot-blotting also showed that the antigen only reacted with Jo-1 antisera.The purified Jo-1 antigen was not stable for long time,but the antigenic activity could maintain for a long time when there was MgCl2 in the solution.Conclusion Affinity chromatography was a simple and easy method for purifying Jo-1 antigen from rabbit thymus.The antigen purified by affinity chromatography could meet the requirement for detecting Jo-1 antibody bydot-blotting.
