Résumé
Objective:To explore the predictive value of low-dose biphasic (inspiratory and expiratory) CT air trapping sign and semi-quantitative score in predicting abnormal blood gas parameters and progression to severe disease in COVID-19 patients.Methods:Patients with non-severe COVID-19 who were diagnosed by nucleic acid testing and hospitalized in designated hospitals in Wuxi City from January 23 to February 29, 2020 were prospectively and consecutively recruited. All patients received low-dose biphasic CT examination on admission and repeated CT examination at regular intervals during the course. On the inspiratory phase admission of the bipolar CT, the scope of the lesion was evaluated by semi-quantitative score, and the air trapping sign on bipolar CT was assessed. The differences of semi-quantitative score, the presence of the air trapping sign and other clinical factors were compared between the patients with abnormal and the normal blood gas index, as well as between the cases progressed to severe disease and cases without disease progression using the independent sample t-test or χ 2 test. The area under the curve (AUC) of receiver operating characteristic (ROC) and the comprehensive discriminant improvement index (IDI) were used to evaluate the predictive effectiveness of the semi-quantitative scores, air trapping sign, and combination of two factors in differentiating cases with abnormal and normal blood gas indexes, as well as in differentiating cases with and without disease progression to severe COVID-19 cases. Results:In total 51 non-severe COVID-19 cases were included, with 16 cases showed air trapping sign during the first biphasic CT examination on admission. During the course of the disease, there were 13 patients with abnormal blood gas index, and 9 cases displaying air trapping sign (9/13). All 7 cases with progression to severe cases showed air trapping sign (7/7). Patients with advanced age, air trapping sign and higher semi-quantitative score were found more likely to have abnormal blood gas index ( t=3.10, χ 2=9.38, t=3.34, P<0.05); patients with advanced age, underlying diseases, air trapping sign and higher semi-quantitative score were more likely to develop into severe disease ( t=2.68, χ 2=6.65, χ 2=4.25, t=4.33, P<0.05). The AUC of semi-quantitative score, air trapping sign and combination of two factors in distinguishing abnormal blood gas index from normal blood gas index was 0.803, 0.754 and 0.794 respectively. The AUC of semi-quantitative score, air trapping sign and combination of two factors in distinguishing cases with progression to severe cases from non-progression was 0.881, 0.898 and 0.932, respectively. Air trapping sign combined with semi-quantitative score significantly improved the prediction effectiveness of disease progression, compared with semi-quantitative score or air trapping sign (IDI=0.271, 0.117). Conclusion:Air trapping sign and semi-quantitative score might be used as effective indicators to predict the progression of COVID-19 cases, and the combination of these two factors might be more helpful to predict the disease progression.
Résumé
Objective To construct, express, purify and screen immunosuppressive molecule against human soluble APRIL (a proliferation-inducing ligand). Methods The cDNA of soluble APRIL (sAPRIL) was mutated and TEL Th epitope was added. Mutants was expressed by pQE-80L/DH5? system, identified by SDS-PAGE and Western blotting, purified by Ni-NTA resin. Their activity on stimulating the proliferation of Raji cell was detected. Results Four sAPRIL mutants were constructed and expressed as follows: HEL Th epitope was added at C end (Ⅰ); HEL Th epitope was added at N end (Ⅱ); the last 45-bp DNA was deleted at C end and HEL Th epitope was added (Ⅲ); the first 45-bp DNA was deleted at N end and HEL Th epitope was added (Ⅳ). Specific protein bands according to mutant Ⅰ-Ⅳ were detected by SDS-PAGE and Western blotting. Mutant protein was purified by Ni-NTA successfully. Mutants Ⅰand Ⅱ promoted cell proliferation remarkably, and mutant Ⅲand Ⅳnot. Conclusion Four sAPRIL mutants was constructed and expressed successfully. Immunosuppressive molecule against sAPRIL that can not promote cell proliferation was screened out, and it laid a foundation for further study on their immunosuppressive function.
Résumé
Objective To construct 6 kinds of human soluble proliferation-inducing ligand (sAPRIL) cDNA mutants. Methods Six pair primers according to the cDNA sequence of human sAPRIL for different mutants were designed as follows: HEL Th epitope was added at C or N end, the last or first 45 bp DNA was deleted and HEL Th epitope was added, the last or first 90 bp DNA was deleted and HEL Th epitope was added. Different enzyme site was designed at 5′ end of 12 primers, BamH Ⅰ or SalⅠ or HandⅢ. At the same time, 2 pairs of HEL Th epitope sequence were designed and synthesized, and different incision enzyme sticky end sequence was added at the 5′ or 3′ end of each epitope DNA. Mutant sequences were amplified by 6 pairs primers with sAPRIL cloning plasmid as template. The PCR fragment was digested and then ligated with the HEL Th epitope DNA that had been reannealed. The ligation fragments of the head were ligated with digested pQE80 vector fragment again, and were transformed into DH5? competent cell. Recombinant plasmids were identified by digestion and sequencing. Results Six sAPRIL cDNA mutant DNA sequences were obtained by PCR, and the expression plasmids of sAPRIL cDNA mutants including HEL Th epitope sequence were constructed successfully. The result of sequencing proved that mutations generated as designed fully. Conclusion Six sAPRIL cDNA mutant expression plasmids were constructed successfully.