Application of oral fluid in SARS-CoV-2 nucleic acid and antibody detection / 中华预防医学杂志

This study aimed to explore the application value of new biological specimen oral fluid in SARS-CoV-2 nucleic acid and antibody detection. Oral fluid and paired respiratory and blood specimens from 7 confirmed cases of two COVID-19 cluster epidemic were collected in Beijing from October to November 2021. SARS-CoV-2 virus and IgG antibody were detected by real time PCR kits and serum antibody detection reagents, and SARS-CoV-2 IgG antibody in oral fluids was detected by a new established method of magnetic particle chemiluminescence. The results showed that the nucleic acid amplification test of SARS-CoV-2 on nasopharyngeal swabs, throat swabs and oral fluid specimens from 3 confirmed cases of COVID-19 was positive, among which the Ct value for ORF1a/b and N gene of oral fluid samples in 2 cases was close to that of throat swab, and the Ct value of oral fluid sample for 1 case was higher than that of throat swab. The complete genome sequence of one oral fluid specimen was obtained, which belonged to the VOC/Delta variant strain. The SARS-CoV-2 IgG antibodies of the paired oral fluid and serum were all positive, and the S/CO values of oral fluid were all lower than those of serum. The series of oral fluid results showed that SARS-CoV-2 IgG antibody level increased from 11 to 32 days after the onset of the disease.

An investigation on serum antibody level of varicella-zoster virus in healthy population in Beijing / 中华预防医学杂志

Objective: To assess the level and trend of varicella-zoster virus (VZV) antibody among healthy population in Beijing in 2017, after the five-year implementation of the two doses varicella vaccination strategy in 2012, and to provide evidence for scientific evaluation of immunization strategy. Methods: A total of 2 144 subjects in ten age groups from 8 districts of Beijing city were recruited in this study using cross-sectional survey based on multi-stage cluster random sampling method. Serum samples were collected and VZV antibody was detected by ELISA. The influencing factors of antibody concentration and positive rate were analyzed and compared with the study in 2012. The antibody concentration and antibody positive rate were analyzed by nonparametric test and χ² test respectively. Results: The ratio of subjects with registered residence in Beijing city to other provinces was 1∶1. The ratio of male to female was 1∶1.08. The median concentration of VZV antibody was 341.4 (78.6, 1 497.8) mIU/ml, and the total antibody positive rate was 71.1% (1 524/2 144). There were significant differences in antibody positive rate (χ²=736.39, P<0.01) and antibody concentration (χ²=740.34, P<0.01) among different age groups. The antibody positive rate generally increased with age (χ²trend=7.32, Ptrend<0.01). Among 862 children under 14 years old, the antibody positive rate of two doses vaccination 72.8% (182/250) was significantly higher than that of one dose vaccination 51.9% (154/297) (χ²=25.14, P<0.01). There was significant difference between 1-4 years old group (χ²=11.71, P<0.01) and 10-14 years old group (χ²=5.95, P=0.02), but not in 5-9 years old group (χ²=3.00, P=0.07). Compared with the study in 2012, the antibody positive rate increased in 5-9 years old group (χ²=14.35, P<0.01) and decreased in 1-4 years old group (χ²=11.51, P=0.01) in 2017. Conclusion: The recommended varicella booster vaccination has significantly improved the VZV antibody level of children in Beijing city. In the future, it is necessary to explore a more optimized two doses varicella vaccination schedule for children in combination with epidemiological evidence.

Predictive value of serum Klotho level for progression of renal function in patients with chronic kidney disease / 临床检验杂志

Objective To observe the relationship between serum Klotho levels and the progression of renal function in patients with chronic kidney disease (CKD)and investigate further the feasibility of serum Klotho levels for predicting the progression of renal function in CKD patients.Methods Eighty-one non-dialysis patients with CKD 3 to 5 stages and 30 healthy volunteers in the First People's Hospital of Kunshan were enrolled for a 12 months of follow-up.The levels of Klotho and fibroblast growth factor 23 (FGF23) in serum were detected by ELISA at the beginning and the end of the follow-up.The other related indicators were also tested simultaneously.GFR values were calculated by MDRD and GC formulas.According to the decreasing range of GFR,the CKD patients were subdivided into two groups:deterioration group and stability group for renal function,and the relationships between Klotho levels and progression of kidney function were evaluated.Results The patients were followed up for an average of (9.5 + 2.9) months.GFR in CKD patients decreased from (24.8 ± 12.4) mL/min to (18.7 ± 12.1) mL/min (P ＜ 0.0 1),and serum Klotho level decreased from 2.53 (1.41,3.67)ng/mL to 1.63 (1.07,3.19)ng/mL (P ＜0.01)with more pronounced trend in the patients with renal function deterioration than the patients in stability group (P ＜0.01).Fifteen patients with high Klotho level suffered from adverse kidney outcomes while 26 ones with lower Klotho level suffered from deterioration of renal function (63.4％ vs 36.5％,P =0.02).KaplanMeier analysis revealed the high risk of adverse kidney outcomes arose in the CKD patients with lower Klotho level (P =0.013).Conclusion Klotho level in CKD patients may significantly decrease and should be more apparent with renal function progresses.Lower Klotho level in serum may be associated with high risk of adverse kidney outcomes and become a promising marker to predict CKD progression.

Detection of large deletions in X linked Alport syndrome using competitive multiplex fluorescence polymerase chain reaction / 北京大学学报(医学版)

Objective:To evaluate the ability of multiplex competitive fluorescence polymerase chain reaction in detection of large deletion and duplication genotypes of X-linked Alport syndrome.Methods:Clinical diagnosis of X-linked Alport syndrome was based on either abnormal staining of type Ⅳ collagen α5 chain in the epidermal basement membrane alone or with abnormal staining of type Ⅳ collagen α5 chain in the glomerular basement membrane and Bowman's capsule/ultrastructural changes in the glomerular basement membrane typical of Alport syndrome.A total of 20 unrelated Chinese patients (13 males and 7 females) clinically diagnosed as X-linked Alport syndrome were included in the study.Their genotypes were unknown.Control subjects included a male patient with other renal disease and two patients who had large deletions in COL4A5 gene detected by multiplex ligation-dependent probe amplification.Genomic DNA was isolated from peripheral blood leukocytes in all the participants.Multiplex competitive fluorescence polymerase chain reaction was used to coamplify 53 exons of COL4A5 gene and four reference genes in a single reaction.When a deletion removed exon 1 of COL4A5 gene was identified,the same method was used to coamplify the first 4 exons of COL4A5 and COL4A6 genes,a promoter shared by COL4A5 and COL4A6 genes,and three reference genes in a single reaction.Any copy number loss suggested by this method was verified by electrophoresis of corresponding polymerase chain reaction amplified products or DNA sequencing to exclude possible DNA variations in the primer regions.Results:Genotypes of two positive controls identified by multiplex competitive fluorescence polymerase chain reaction were consistent with those detected by multiplex ligation-dependent probe amplification.Deletions were identified in 6 of the 20 patients,including two large deletions removing the 5'part of both COL4A5 and COL4A6 genes with the breakpoint located in the second intron of COL4A6,two large deletions removing more than 30 exons of COL4A5 gene,one large deletion removing at least 1 exon of COL4A5 gene,and one small deletion involving 13 bps.No duplication was found.Conclusion:Our results show that multiplex competitive fluorescence polymerase chain reaction is a good alternative to classical techniques for large deletion genotyping in X-linked Alport syndrome.

Establishment of minireplicon system for severe fever with thrombocytopenia syndrome bunyavirus / 病毒学报

Severe fever with thrombocytopenia syndrome bunyavirus is a newly emerging virus in China, enveloped with a tripartite, single-stranded RNA genome of negative polarity. The regulatory elements for viral transcription and replication, as well as encapsidation and packaging signals, are thought to be located within these noncoding regions (NCRs). The terminal nucleotides are genus specific and highly conserved. The function of the remaining nucleotides of the NCRs is still not well understood. In this study, we developed the plasmid-driven RNA polymerase I minireplicon system for SFTSV firstly, using reporter genes GFP and luciferase. The function of the noncoding regions of the three Bunyaviridae RNA segments (L, M, S) in transcription was analyzed. Reporter genes are successfully expressed in SFTSV minireplicon system. Our results suggest that the NCRs of SFTSV from all three segments contain the necessary signals to initiate transcription. Quantitative detection of the luciferase expression level shows that promoter activity in the three segments is different.