Clinical Diagnostic Value of Serum 25-Hydroxyvitamin D in Severe Fever with Thrombocytopenia Syndrome.

Purpose: Severe Fever with Thrombocytopenia Syndrome (SFTS) is an infectious disease with rapid onset and high case fatality rate. The study was to explore the clinical value by examining the serum level of 25-hydroxyvitamin D (25 (OH) D) in SFTS patients. Methods: One hundred and five patients and 156 healthy controls were included. Univariate and multivariate regression analyses were performed to identify independent risk factors for disease progression. Subject operating characteristics (ROC) curves were drawn, and the corresponding area under the curve (AUC) was calculated to assess the sensitivity and specificity of the diagnostic disease. Results: The 25 (OH) D level of disease group was lower than that of healthy control group (22.12 (18.43, 25.86) ng/mL vs 27.36 (23.20, 32.71) ng/mL; P<0.05). The 25 (OH) D level of severe disease group was lower than that of mild disease group (20.55(16.30, 24.44) ng/mL vs 24.94(20.89, 31.91) ng/mL; P<0.05). And there was no significant difference of 25 (OH) D level between the survival group and death group in severe disease group. Multivariate Logistic regression analysis showed that the 25 (OH) D level under 19.665 ng/mL was an independent risk factor for the development of SFTS (OR = 0.901, P=0.040). Furthermore, age more than 68.5 years old and lactate dehydrogenase (LDH) more than 1023.5U/L were independent risk factors for death in severe patients with SFTS. Conclusion: Patients with SFTS have reduced 25 (OH) D level, and 25 (OH) D is a risk factor for disease severity in patients with SFTS. Vitamin D supplementation may be an effective measure to reduce the risk of infection and improve the prognosis.

Lymphocyte-monocyte-neutrophil index: a predictor of severity of coronavirus disease 2019 patients produced by sparse principal component analysis.

BACKGROUND: It is important to recognize the coronavirus disease 2019 (COVID-19) patients in severe conditions from moderate ones, thus more effective predictors should be developed. METHODS: Clinical indicators of COVID-19 patients from two independent cohorts (Training data: Hefei Cohort, 82 patients; Validation data: Nanchang Cohort, 169 patients) were retrospected. Sparse principal component analysis (SPCA) using Hefei Cohort was performed and prediction models were deduced. Prediction results were evaluated by receiver operator characteristic curve and decision curve analysis (DCA) in above two cohorts. RESULTS: SPCA using Hefei Cohort revealed that the first 13 principal components (PCs) account for 80.8% of the total variance of original data. The PC1 and PC12 were significantly associated with disease severity with odds ratio of 4.049 and 3.318, respectively. They were used to construct prediction model, named Model-A. In disease severity prediction, Model-A gave the best prediction efficiency with area under curve (AUC) of 0.867 and 0.835 in Hefei and Nanchang Cohort, respectively. Model-A's simplified version, named as LMN index, gave comparable prediction efficiency as classical clinical markers with AUC of 0.837 and 0.800 in training and validation cohort, respectively. According to DCA, Model-A gave slightly better performance than others and LMN index showed similar performance as albumin or neutrophil-to-lymphocyte ratio. CONCLUSIONS: Prediction models produced by SPCA showed robust disease severity prediction efficiency for COVID-19 patients and have the potential for clinical application.

A new and rapid approach for detecting COVID-19 based on S1 protein fragments.

The pandemic of novel coronavirus disease 2019 (COVID-19) seriously threatened the public health all over the world. A colloidal gold immunochromatography assay for IgM/IgG antibodies against the receptor-binding domain of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) S1 protein was established to assess its rapid diagnostic value. We first designed and manufactured all contents of the test cassette of SARS-CoV-2 rapid test kit: the colloidal gold-labeled mouse-antihuman lgM/lgG antibody, the recombinant SARS-CoV-2 antigen, the nitrocellulose membrane control line, and specimen diluents. Furthermore, reverse transcription-polymerase chain reaction (RT-PCR) assay, colloidal gold immunochromatography assay, serological validation of cross reaction with other common viruses, and clinical validation were performed. The kit was finally evaluated by 75 serum/plasma samples of SARS-CoV-2 infection cases and 139 healthy samples as control, with the result of that the sensitivity, specificity, and accuracy for IgM were 90.67%, 97.84%, and 95.33%, whereas for IgG were 69.33%, 99.28%, and 88.79%, respectively; the combination of IgM and IgG could improve the value: 92.00%, 97.12%, and 95.33%, respectively. Therefore, the rapid detection kit has high sensitivity and specificity, especially for IgM&IgG, showing a critical value in clinical application and epidemic control of COVID-19.