Immunoglobulin G4 autoimmune diseases (IgG4-AID) is the general name of a series of autoimmune diseases, including membranous nephropathy, pemphigus and myasthenia gravis. It is mainly characterized by the existence of IgG4 autoantibodies in patients. At present, a variety of IgG4-AID-related autoantigens have been found, which mainly exist in kidney, skin, central and peripheral nervous system, blood circulation or vascular system. Compared with IgG autoantibodies, various IgG4 autoantibodies have better clinical significance or clinical-laboratory value in the diagnosis, differential diagnosis, treatment and prognosis judgment of some IgG4-AID. This article reviews the research progress of IgG4 autoantibodies in IgG4-AID.

Objective:To investigate the diagnostic value of Flt3 ligand (Flt3L) and growth arrest specific protein 6 (Gas6) in post-chemotherapy infection of patients with non-Hodgkin′s lymphoma.Methods:A total of 94 NHL patients admitted to Wuhan No.1 Hospital for chemotherapy from July 2019 to October 2020 were collected, and divided into infection group ( n=40) and non-infection group ( n=54). Fifty healthy subjects at the same period were selected as the control group to analyze the expression levels of Flt3L, Gas6 and general inflammatory indicators among the three groups. The relationship between Flt3L, Gas6 and general inflammatory indicators were analyzed. The predictive value of Flt3L and Gas6 for post-chemotherapy infection in NHL patients was analyzed by ROC curve. Kaplan-Meier curve was used to analyze the infection status of NHL chemotherapy patients with serum Flt3L and Gas6 levels. Results:The levels of serum Flt3L [807.80(215.10-1 232.00) pg/ml] and Gas6 [20.04(13.14-27.52) ng/ml] in the infection group were higher than those in the non-infection group and the control group, and the differences were statistically significant (all P<0.05);The levels of serum Flt3L[887.3(321.60-1 367.00) pg/ml] and Gas6[25.24(17.61-42.86) ng/ml] in the severely infection group were higher than those in the mildly infection group, and the differences were statistically significant (all P<0.05). serum Flt3L was negatively correlated with WBC and positively correlated with IL-6;serum Gas6 was negatively correlated with WBC.ROC curve analysis showed that the AUC and 95% CI of Flt3L and Gas6 were 0.814 (0.718-0.909) and 0.644 (0.523-0.765), respectively. The combined application of serum Flt3L with hsCRP, PCT and IL-6 significantly improved the diagnostic efficiency, and the area under the curve was 0.956, 0.923 and 0.865, respectively. Kaplan-Meier curve analysis showed that when serum Flt3L≥649.80 pg/ml and serum Gas6≥21.50 ng/ml in NHL chemotherapy patients, the infection rate was significantly increased ( P all<0.05). Conclusion:Serum Flt3L and Gas6 levels in post chemotherapy-infection of NHL patients were significantly increased and correlated with the severity of infection. Early detection of serum Flt3L levels is helpful to predict the diagnosis of infection in NHL patients after chemotherapy.

Viruses infect host cells by binding to receptors on thesurface of cells. Receptor is an important factor affecting host range and interspecific transmission. In December 2019, an outbreak of unexplained pneumonia occurred in Wuhan, Hubei province. The pathogen was a new coronavirus, named 2019 NovelCoronavirus (2019-nCoV) by WHO. Angiotensin-converting enzyme 2 (ACE2) was found to be the receptor of 2019-nCoV.This review provides a brief overview of human coronavirus receptors and their applications, with a view to providing references for the tracing, cross-species transmission, epidemiological analysis and antiviral and vaccine studies of 2019-nCoV.

Objective: To analyze the alterations and clinical significance of serum calcium binding protein S100A8/A9 and soluble receptor for advanced glycation end products (sRAGE) levels in patients with chronic obstructive pulmonary disease(COPD). Methods: Enzyme-linked immonosorbent assay was established to detect serum levels of S100A8/A9 and sRAGE in 203 patients with COPD[male166, female 37, aged 52-92 years, average years(69.72±9.079)] and in 41 smoking elderly non-COPD patients[male 35,female 6, aged 55-89 years, average years(68.66±8.74)], and 167 non-smoking healthy subjects as the control group[male 132, female 35, aged 57-92 years, average years(69.13±7.21)] from April 2018 to January 2019. The relationship between the S100A8/A9, sRAGE and clinical biomarkers [the percentage of fored expiratory volume in one second(FEV₁) in the predicted value, FEV₁/fored vital capacity(FVC), neutrophile granulocyte(NEU)%, pack-year] were investigated. The diagnostic value of S100A8/A9, sRAGE and their combined detection for COPD was analyzed using the subject operating characteristic curve. Results: The serum S100A8/A9 level [(2.70±1.11)μg/ml] in COPD patients was significantly higher than that in the smoking control group [(1.65±0.63) μg/ml] and the non-smoking control group[(0.99±0.48)μg/ml], t=5.807, P<0.000 1; t=18.45, P<0.000 1. The serum S100A8/A9 levels in patients with COPD[GOLD Ⅰ(2.08±1.08) μg/ml, GOLDⅡ (2.58±1.06) μg/ml, GOLD Ⅲ (2.69±1.12) μg/ml, GOLDⅣ (2.95±1.10)μg/ml] were significantly higher than the non-smoking control group(0.99±0.48)μg/ml, t=6.616, P<0.000 1; t=14.56, P<0.000 1; t=17.10, P<0.000 1; t=18.09, P<0.000 1.The serum sRAGE level [(0.29±0.25)ng/ml] in COPD patients was significantly higher than that in the smoking control group[(0.60±0.24)ng/ml] and the non-smoking control group[(0.85±0.35)ng/ml], t=7.367, P<0.000 1; t=18.14, P<0.000 1. The serum sRAGE levels in patients with COPD[GOLD Ⅰ(0.46±0.40),GOLDⅡ (0.28±0.25),GOLD Ⅲ (0.29±0.25),GOLD Ⅳ (0.25±0.19)ng/ml] were significantly lower compared with non-smoking control group[(0.85±0.35)ng/ml], t=3.459, P=0.000 5; t=10.23, P<0.000 1; t=13.95, P<0.000 1; t=11.70, P<0.000 1. Serum S100A8/A9 levels were positively correlated with smoking amount and NEU% (r=0.458 5, P<0.000 1; r=0.228 3, P=0.001 1), negatively correlated with FEV₁/FVC, the percentage of FEV₁ in the predicted value, and sRAGE(r=-0.190 6, P=0.006 4; r=-0.186 3, P=0.007 8; r=-0.201 7, P=0.003 9). sRAGE levels were negatively correlated with NEU% (r=-0.155 9, P=0.026 4). In the ROC curve, the area under the curve of S100A8/A9, sRAGE and combined detection were 0.922[95%CI(0.897-0.947)], 0.926[95%CI(0.899-0.952)]and 0.966 [95%CI(0.950-0.983)], respectively. Conclusion S100A8/A9 and sRAGE are closely correlated with the degree of airflow constrains and the levels of serum inflammatory mediators, which are expected to be as potential biomarkers of COPD.

Objective To investigate the value of F-actin autoantibodies in the serum of patients with systemic lupus erythematosus (SLE),and to explore the relationships between F-actin autoantibodies and other clinical indicators.Methods ELISA was established to detect serum levels of F-actin autoantibodies in 93 inpatients with SLE from March 2017 to January 2018 (case group,n=93),72 patients with rheumatoid arthritis (RA) (disease control group) and 83 healthy subjects (healthy control group) were included during the same period.The positive rates of F-actin autoantibodies between the case group and the two control group were compared.Clinical data including SLE disease activity index (SLEDAI),immuno-globulin (lg)G,erythrocyte sedimentation rate (ESR),anti-dsDNA,and antinuclear antibody (ANA) of 93 patients with SLE were collected and the correlation analysis between F-actin autoantibodies units was applied respectively.The diagnostic performance of F-actin autoantibodies in SLE was analyzed by using the receiver operating characteristic curve (ROC).T test,Chi-square test and Spearman/Pearson correlation analysis were applied for statistical analysis.Results The serum levels of F-actin autoantibodies in the SLE case group,disease control group,and healthy control group were (18±13),(12±6),and (11±5) U,respectively,the differences between SLE case group and disease control group,and healthy control group were significant (t=3.163,P=0.001 9;t=4.436,P＜0.01).The positive rates of F-actin autoantibodies were 33％(31/93) in patients with SLE,10％(7/72) in disease control group,and 4％(3/83) in healthy control group.The F-actin autoanti-bodies units in SLE were correlated with SLEDAI,IgG,ESR,anti-dsDNA,and ANA (r=0.273 7,P=0.008 3;r=0.558 7,P＜0.01;r=0.419 9,P=0.000 1,r=0.351 4,P=0.001 1,r=0.460 9,P＜0.01),in which F-actin autoantibodies units showed significant correlation with IgG and ANA.In the ROC curve,the area under the curve(AUC) was 0.62 [95％CI(0.54,0.70)],P=0.001 3.which was statistically significant.When the cut-off value of the F-actin autoantibodies was 14.04 U,the Youden's index (YI) was the largest (YI=0.30),and the sen-sitivity for the diagnosis of SLE was 0.77,the specificity was 0.53.Conclusion The positive rate of F-actin autoantibodies in the serum of patients with SLE is higher than that of RA and healthy controls,so it has certain diagnostic value for SLE.The F-actin autoantibodies units is correlated with both SLEDAI,ESR,and anti-dsDNA,suggesting that F-actin autoantibodies units may be a new biomarker for disease activity assessment of SLE patients.

Idiopathic pulmonary fibrosis (IPF) is a specific form of chronic, progressive, fibrosing interstitial pneumonia of unknown etiology , a median survival time of which is 2 to 3 years.The diagnosis and treatment are important for IPF in time.Krebs von den lungen-6(KL-6), Surfactant protein-A(SP-A) and Surfactant protein-D(SP-D) are acceptable biomarkers in clinical for idiopathic pulmonary fibrosis in Japan,which have shown good sensitivity at diagnosis IPF and predict the prognoses for patients with IPF . However , the differential diagnosis of IPF from other interstitial lung diseases is still challenging .Other biomarkers are being developed , one of which would have the best specificity and sensitivity at diagnosis IPF.Those biomarkers about pathogenesis of IPF includes alveolar epithelial cell dysfunction , fibrogenesis and immune dysregulation are shown .They are potential to account for underlying disease mechanisms , accelerated drug development and advance clinical management.

Autoimmune blistering skin diseases are a group of organ-specific autoimmune disorders that are characterized by autoantibodies against desmosome and hemidesmosome which are structural proteins of the epidermis or the dermal-epidermal junction and clinically by blisters and erosions on skin and/or mucous membranes.According to the skin level at which the blister occurs and the structural proteins that the autoantibodies target,autoimmune blistering diseases can be categorized into intraepithelial blister group and subepidermal blister group.The treatment options and prognosis are different among the various diseases.Since clinical criteria and histopathological characteristics are not sufficient for an accurate diagnosis of autoimmune blistering skin diseases,direct immunofluorescence microscopy,indirect immunofluorescence microscopy,ELISA,immunoblotting and immunoprecipitation are needed for exact diagnosis.The detection of serum autoantibodies have been shown to correlate with disease activity and thus may be helpful in deciding treatment options for the patients.

Objective To verify the performance of quantitative detection of interleukin-6 by using IMMUNITE1000 chemilumi-nescence analyzer.Methods According to the requirements of International Organization for Standardization(ISO)1 5 189,serum specimen were collected and levels of IL-6 were detected.The precision,accuracy,analytical measurement range,reportable range amd normal reference range of quantitative detection of interleukin-6 by using IMMUNITE1000 chemiluminescence analyzer were verified,and its performance was evaluated.Results The coefficient variation(CV)of between-day precision of high and low value was 6.42% and 1.97% respectively,and that of within-run precision was 3.40% and 3.82% respectively.Compared the test re-sults with the target values,the bias % was 0.91%.The regression equation:Y =0.986X - 7.1 (r 2 = 0.999,P < 0.05 ).With 27 times diluted,the recovery rate was from 97% to 100%,and the clinical reportable range was 2 to 27 000 pg/mL.The 95% refer-ence interval ranged from 0 to 5.3 pg/mL.Conclusion The performance of this system meets the manufacturer′s declaration,and could satisfy the quality requirements of clinical laboratory.

Objective To investigate clinical significance of plasma D-dimer (D-D),fibrinogen (FIB) and fibrin/fibrinogen degradation product (FDP) in patients with chronic obstructive pulmonary disease (COPD).Methods The level of plasma D-D,FIB and FDP in 150 patients with COPD and 80 healthy persons were detected,and compared.Results The level of plasma D-D,FIB and FDP in COPD patients were significantly higher than those in healthy persons[(2.16 ± 0.61) mg/L vs.(0.55 ± 0.04) mg/L,(5.88 ± 1.52) g/L vs.(3.12 ± 0.35) g/L,(7.18 ± 1.63) mg/L vs.(3.62 ± 1.55) mg/L],there were significant differences (P ＜ 0.01).Conclusion Monitoring the level of plasma D-D,FIB and FDP in COPD patients can provide reliable basis in hypercoagulable state and primary and secondary hyperfibrinolysis.

Impaired clearance of apoptotic cells is important in the pathogenesis of autoimmune disease.C-reactive protein (CRP) is an acute phase protein that plays a major role in the regulation of the autoimmune and inflammatory response .CRP has a role in the clearance of bacteria and dying and altered cells through binding to phosphocholine and might also have more complex immunomodulatory functions . CRP function as opsonins for pathogens and dying and apoptotic cells through activation of the complement pathway and through binding to Fcγreceptors , and is associated with the clearance of apoptotic cells and nuclear antigen , thus becoming a protective molecule against pathogenic autoimmune responses in general . Measurement of serum CRP level is in widespread clinical use as a sensitive marker of inflammation and autoimmune disease , particularly in relation to the use of the CRP-based disease activity score in the evaluation of rheumatoid disease.