Influential factor and trend of specific IgG antibody titer in coronavirus disease 2019 convalescents / 中南大学学报(医学版)

OBJECTIVES@#To explore the influential factors and titer trend of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) specific IgG antibody in convalescent patients with coronavirus disease 2019 (COVID-19), and to provide theoretical basis for the feasibility of clinical treatment of convalescent plasma.@*METHODS@#Colloidal gold immunochromatography assay was used to detect the SARS-CoV-2 specific IgG antibody and its titer in 113 convalescent patients with COVID-19 who were followed up from February 19, 2020 to April 6, 2020. The basic characteristics and treatment factors of patients in the high titer group (antibody titer≥1꞉160, @*RESULTS@#The difference in the clinical type of COVID-19, onset time, first admission C-reactive protein, absolute value of lymphocyte, absolute value of CD19@*CONCLUSIONS@#Male COVID-19 patients might be more likely to produce high titer SARS-CoV-2 specific IgG antibodies than female. The peak level of SARS-CoV-2 specific IgG antibody in convalescent patients is maintained for a short period. Using plasma from convalescent COVID-19 patients for treatment should be within 28 d after discharge.

Effect of transfusion convalescent recovery plasma in patients with coronavirus disease 2019 / 中南大学学报(医学版)

OBJECTIVES@#To evaluate curative effects of coronavirus disease 2019 (COVID-19) patients by the transfusion of other convalescent plasma.@*METHODS@#Retrospective analysis of the clinical data of 18 patients with severe and critical COVID-19, who were hospitalized in the ICU of Xianghu Branch of the First Affiliated Hospital of Nanchang University from February 1 to March 15, 2020. Patients were subdivided into an experimental group (=6, who had transfused the plasma) and an observation group (=12, who had no plasma transfusion). Basic clinical data and prognosis indexes of these two groups were compared. Moreover, for the experimental group, the dynamic changes of blood oxygen saturation before and after the transfusion, the changes of lymphocyte absolute value 48 hours after the transfusion, and the detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) nucleic acid were analyzed.@*RESULTS@#There were no significant differences in age, gender, blood type and other basic clinical data between the two groups (all >0.05).There were no significant differences in ventilator machine weaning time, extracorporeal membrane oxygenation (ECMO) weaning time, body temperature recovery to normal time, and hospitalization days between these two groups (all >0.05). For the experimental group, before, during and after the convalescent plasma transfusion, the blood oxygen saturation of all 6 patients at all time (1, 6, 8, 12, 24, 36, and 48 h) was more than 90%, and there was no significant fluctuation. There were 3 patients whose absolute value of lymphocyte was increased 48 hours after the transfusion, and the remaining was decreased. There were 5 patients whose SARS-CoV-2 nucleic acid detection turned negative 48 hours after the transfusion, accounting for 83.3%.@*CONCLUSIONS@#Transfusion of convalescent plasma will not affect outcomesof COVID-19 patients, which can neutralize SARS-CoV-2 in patients and reduce the loading capacity of SARS-CoV-2.

Mechanisms regulating p21 gene expression by retinoic acid-induced gene G protein / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To investigate the mechanisms by which retinoic acid-induced gene G (RIG-G) protein regulates p21 gene expression.</p><p><b>METHODS</b>Western blot was used to detect the effects of RIG-G protein overexpression on p21 protein expression level in leukemia cell line NB4 cells and the phosphorylation of both c-Jun and JNK in U937 cells. The c-Jun expression plasmid and p21 gene promoter-containing reporter plasmid were co-transfected into 293T cells, to explore the regulatory effect of c-Jun protein on p21 gene expression by luciferase reporter assay.</p><p><b>RESULTS</b>Western blot showed that the overexpression of RIG-G protein significantly upregulated p21 protein level in the NB4 cells, and the level of p21 protein largely increased along with the induction of endogenous RIG-G protein during the differentiation of NB4 cells treated by all-trans retinoic acid (ATRA). Moreover, the phosphorylation of both c-Jun and JNK decreased in RIG-G-overexpressing U937 cells while total c-Jun and JNK proteins remained unchanged. After using the JNK inhibitor SP600125 to block JNK phosphorylation, the level of c-Jun phosphorylation was still dramatically reduced in the RIG-G-overexpressing U937T-RIG-G cells, compared with the control U937T-pTRE cells. These results indicated that the inhibitory effect of Rig-G protein on c-Jun phosphorylation could not only be through the JNK pathway, but also via some JNK-independent pathways. Luciferase reporter assay showed that when 0.1, 0.5, 1.0 and 2.0 µg c-Jun-expressing plasmids were respectively transfected into 293T cells, compared with the empty vector-transfected group, the relative luciferase activities were (83.0 ± 1.7)%, (73.7 ± 0.7)%, (68.9 ± 0.9)% and (64.1 ± 0.9)%, indicating that the transcriptional activity of p21 gene could be inhibited by c-Jun protein.</p><p><b>CONCLUSIONS</b>RIG-G protein may suppress the phosphorylation of c-Jun protein through different signal pathways, thereby increasing the expression of p21 gene, arresting the cell cycle and inhibiting the cell growth in U937 cells.</p>