IgG₄ is a subclass of IgG. Elevated serum IgG₄ levels are an important serological feature of IgG₄ related diseases and serve as a serological marker for assessing disease activity and severity. The harmonization of IgG₄ detection is crucial for its clinical application. National Clinical Research Center for Dermatologic and Immunologic Diseases (Peking Union Medical College Hospital), Experimental Diagnosis Research Committee, Rheumatology and Immunology Physicians Committee of Chinese Medical Doctor Association, Autoantibodies Detection Committee, and Chinese Rheumatism Data Center have organized clinical and laboratory experts to draft this consensus, aiming to standardize IgG₄ detection and provide guideline for clinician and laboratory experts to appropriate utility and interpret IgG₄ results in China.
Humans ; China ; Consensus ; Immunoglobulin G/blood*

OBJECTIVE: This study prospectively investigates the association between immunoglobulin G (IgG) N-glycan traits and ischemic stroke (IS) risk. METHODS: A nested case-control study was conducted in the China suboptimal health cohort study, which recruited 4,313 individuals in 2013-2014. Cases were identified as patients diagnosed with IS, and controls were 1:1 matched by age and sex with cases. IgG N-glycans in baseline plasma samples were analyzed. RESULTS: A total of 99 IS cases and 99 controls were included, and 24 directly measured glycan peaks (GPs) were separated from IgG N-glycans. In directly measured GPs, GP4, GP9, GP21, GP22, GP23, and GP24 were associated with the risk of IS in men after adjusting for age, waist and hip circumference, obesity, diabetes, hypertension, and dyslipidemia. Derived glycan traits representing decreased galactosylation and sialylation were associated with IS in men (FBG2S2/(FBG2 + FBG2S1 + FBG2S2): odds ratio ( OR) = 0.92, 95% confidence interval ( CI): 0.87-0.97; G1 ⁿ: OR = 0.74, 95% CI: 0.63-0.87; G0 ⁿ: OR = 1.12, 95% CI: 1.03-1.22). However, these associations were not found among women. CONCLUSION This study validated that altered IgG N-glycan traits were associated with incident IS in men, suggesting that sex discrepancies might exist in these associations.
Male ; Humans ; Female ; Immunoglobulin G/metabolism* ; Ischemic Stroke ; Case-Control Studies ; Cohort Studies ; Glycosylation ; Polysaccharides

Objective To investigate the preventive therapeutic effect and possible mechanism of single chain variable fragments chimeric protein (SD) of ovalbumin epitopes internalizing receptor DEC-205 antibody on food allergy in mice. Methods Mice were randomly divided to five groups (control, PBS, scFv DEC 100 μg, SD 50 μg, SD 100 μg) and treated for 24 hours before OVA administration. After challenge, the serum level of OVA-specific IgE, IgG1, IgG2a and IL-4 were detected by ELISA. Infiltration of eosinophils and mast cells in the jejunum was observed by HE staining and toluidine blue staining respectively. The bone marrow of tibia and femur was isolated and cultured to obtain immature dendritic cells(BMDCs), which were further treated with LPS (10 ng/mL), TSLP (50 ng/mL), scFv DEC protein (1000 ng/mL) and SD protein (10,100,1000)ng/mL for 24 hours, and the IL-10 level of supernatant was assayed by ELISA. Results Compared with PBS group, the number of SD-treated mice with diarrhea was markedly reduced. The difference in rectal temperature and the levels of serum OVA-specific IgE, IgG1, IgG2a and IL-4 decreased significantly after prophylactic administration of SD; The number of eosinophils and mast cells in jejunum also decreased significantly while the IL-10 level in the supernatant of BMDCs increased significantly after SD intervention. Conclusion SD mitigates experimental FA response by fosters the immune tolerance property of dendritic cells.
Mice ; Animals ; Ovalbumin ; Interleukin-10 ; Single-Chain Antibodies/genetics* ; Immunoglobulin E ; Epitopes/therapeutic use* ; Interleukin-4 ; Food Hypersensitivity/prevention & control* ; Immunoglobulin G ; Recombinant Fusion Proteins/genetics* ; Mice, Inbred BALB C ; Disease Models, Animal

Objective To prepare specific mouse monoclonal antibody (mAb) against human adenovirus type 55 Hexon protein (HAdV55 Hexon). Methods The Hexon genes of HAdV55, 3, 4, 7, 16 and 21 were chemically synthesized as templates for PCR amplification. The prokaryotic expression plasmids pET28a-HAdV55 Hexon and eukaryotic expression plasmids pCAGGS-HAdV3, 4, 7, 16, 21 and 55 Hexon were constructed respectively. The pET28a-HAdV55 Hexon plasmid was transformed into E. coli competent cell BL21 (DE3) and was induced by IPTG. After the purified inclusion body was denatured and renatured, Hexon55 protein was purified by tangential flow filtration system. pCAGGS-HAdV55 Hexon was used to immunize BALB/c mice by cupping, and HAdV55 Hexon protein was used to booster immunization. The anti-HAdV55 Hexon mAb was prepared by hybridoma technique and the titer and subclass were determined. The specificity of antibody was identified by Western blot using HEK293T cells transfected with pCAGGS-HAdV55 Hexon and by immunofluorescence assay (IFA) using BHK cells transfected with pCAGGS-HAdV55 Hexon. Both clones with high titer were selected, and the cross-reactivity of pCAGGS-HAdV3, 4, 7, 16, 21 and 55 Hexon transfected cells were analyzed by Western blot analysis and IFA. Results PET28a-HAdV55 Hexon and pCAGGS-HAdV55 Hexon, 3, 4, 7, 16 and 21 expression plasmids were successfully constructed. BL21 transformed with pET28a-HAdV55 Hexon was induced by IPTG. The HAdV55 Hexon protein was mainly expressed in the form of inclusion body. After denaturation and renaturation, the purified HAdV55 Hexon protein was obtained by ultrafiltration. Six hybridoma cell lines secreting HAdV55 Hexon mAb were obtained. The antibody subclass analysis showed that 2 strains were IgG2a subtypes and 4 strains were IgG2b. Two specific HAdV55 Hexon antibodies with high titer were obtained, and there was no cross-reactivity with HAdV3, 4, 7, 16, 21 Hexon. Conclusion The specific mice mAb against HAdV55 Hexon provides an experimental basis for establishing its antigen detection method.
Animals ; Mice ; Humans ; Adenoviruses, Human/genetics* ; Escherichia coli/genetics* ; HEK293 Cells ; Isopropyl Thiogalactoside ; Blotting, Western ; Immunoglobulin G ; Antibodies, Monoclonal ; Antibody Specificity ; Mice, Inbred BALB C

OBJECTIVE: To analyze the effect of CD56 expression on the prognosis of newly diagnosed multiple myeloma (MM) patients and explore the relationship between CD56 with clinical characteristics. METHODS: In this retrospective study, the clinical data and laboratory parameters of 175 newly diagnosed MM patients from February 2015 to December 2020 in the Second Hospital of Anhui Medical University were collected. The patients were divided into CD56⁺ and CD56^- groups based on the expression of CD56, and the general data and laboratory parameters of the two groups were compared. The patients were followed up to June 30, 2021, and progression-free survival (PFS) and overall survival (OS) were recorded. PFS and OS curves of the two groups were plotted respectively, and the survival differences were compared. Univariate and multivariate Cox regression analyses were performed to analyze the effect of CD56 on the prognosis of newly diagnosed MM patients. RESULTS: In 175 newly diagnosed MM patients, 57(32.6%) cases were in the CD56^-group and 118 (67.4%) cases in the CD56⁺ group. There was significant correlation between CD56 expression and ISS stage, ECOG score, platelets, β₂-microglobulin, creatinine, and extramedullary disease (all P <0.05). The incidence of extramedullary disease in the CD56^- group was significantly higher than that in the CD56⁺ group (29.8% vs 12.7%, P =0.006). The median follow-up time of the whole cohort was 23.6 (1.0-78.6) months. The median PFS of patients in CD56⁺ group and CD56^- group were 18.6 (1.2-77.6) and 12.2 (1.0-49.0) months, respectively, and the median OS of the two groups were 27.6 (1.4-77.7) and 19.7 (1.0-78.6) months, respectively. The 2-year PFS rate in the CD56⁺ group was significantly higher than that in the CD56^- group (57.6% vs 36.8%, P =0.010), and the 2-year OS rate in the CD56⁺ group was higher than that in the CD56^- group, but it didn't reach statistical significance (74.6% vs 64.9%, P =0.158). The results of univariate Cox regression analysis showed that the PFS was significantly shorter in newly diagnosed MM patients with advanced age, type IgG, high ECOG score, decreased platelet count, increased lactate dehydrogenase level, extramedullary disease, and CD56^- (all P <0.05), the OS was significantly shorter in patients with high ECOG score, decreased platelet count, increased lactate dehydrogenase level, extramedullary disease, and CD56^- (all P <0.05). The results of multivariate Cox regression analysis showed that advanced age, type IgG, elevated lactate dehydrogenase level, extramedullary disease, and CD56^- were independent prognostic factors for poor PFS (all P <0.05); and decreased platelet count, elevated lactate dehydrogenase level, and extramedullary disease were independent adverse prognostic factors for OS (all P <0.05), while there was no significant independent correlation between CD56 and OS (P >0.05). CONCLUSION Most of the newly diagnosed MM patients have positive expression of CD56. Loss of CD56 expression was associated with unfavorable biological and clinical parameters and poor prognosis, suggesting that CD56 has important clinical value in the prognosis of newly diagnosed MM patients.
Humans ; Immunoglobulin G ; Lactate Dehydrogenases ; Multiple Myeloma/diagnosis* ; Prognosis ; Retrospective Studies

An epidemiological investigation was conducted on a cluster epidemic of COVID-19 in the vaccinated population in Beijing in 2022, and serum samples were collected from 21 infected cases and 61 close contacts (including 20 cases with positive nucleic acid in the isolation observation period). The results of antibody detection showed that the IgM antibody of two infected persons was positive, and the IgG antibody positive rates of patients who were converted, not converted to positive and infected persons were 36.84% (7/19), 63.41% (26/41) and 71.43% (15/21), respectively. About 98.78% of patients had been vaccinated with the SARS-CoV-2 inactivated vaccine. The positive rate of IgG antibody in patients immunized with three doses of vaccine was 86.00% (43/50), which was higher than that in patients with one or two doses [16.12% (5/31)]. The antibody level of M (Q₁, Q₃) in patients immunized with three doses was 4.255 (2.303, 7.0375), which was higher than that in patients with one or two doses [0.500 (0.500, 0.500)] (all P values<0.001). The antibody level of patients who were vaccinated less than three months [7.335 (1.909, 7.858)] was higher than that of patients vaccinated more than three months after the last vaccination [2.125 (0.500, 4.418)] (P=0.007). The positive rate and level of IgG antibody in patients who were converted to positive after three doses were 77.78% (7/9) and 4.207 (2.216, 7.099), respectively, which were higher than those in patients who were converted after one or two doses [0 and 0.500 (0.500, 0.500)] (all P values<0.05).
Humans ; COVID-19 ; SARS-CoV-2 ; Disease Outbreaks ; COVID-19 Vaccines ; Immunoglobulin G ; Antibodies, Viral

Objective: To investigate the value of plasma cells for diagnosing lymph node diseases. Methods: Common lymphadenopathy (except plasma cell neoplasms) diagnosed from September 2012 to August 2022 were selected from the pathological records of Changhai Hospital, Shanghai, China. Morphological and immunohistochemical features were analyzed to examine the infiltration pattern, clonality, and IgG and IgG4 expression of plasma cells in these lymphadenopathies, and to summarize the differential diagnoses of plasma cell infiltration in common lymphadenopathies. Results: A total of 236 cases of lymphadenopathies with various degrees of plasma cell infiltration were included in the study. There were 58 cases of Castleman's disease, 55 cases of IgG4-related lymphadenopathy, 14 cases of syphilitic lymphadenitis, 2 cases of rheumatoid lymphadenitis, 18 cases of Rosai-Dorfman disease, 23 cases of Kimura's disease, 13 cases of dermal lymphadenitis and 53 cases of angioimmunoblastic T-cell lymphoma (AITL). The main features of these lymphadenopathies were lymph node enlargement with various degrees of plasm cell infiltration. A panel of immunohistochemical antibodies were used to examine the distribution of plasma cells and the expression of IgG and IgG4. The presence of lymph node architecture could help determine benign and malignant lesions. The preliminary classification of these lymphadenopathies was based on the infiltration features of plasma cells. The evaluation of IgG and IgG4 as a routine means could exclude the lymph nodes involvement of IgG4-related dieases (IgG4-RD), and whether it was accompanied by autoimmune diseases or multiple-organ diseases, which were of critical evidence for the differential diagnosis. For common lesions of lymphadenopathies, such as Castleman's disease, Kimura's disease, Rosai-Dorfman's disease and dermal lymphadenitis, the expression ratio of IgG4/IgG (>40%) as detected using immunhistochemistry and serum IgG4 levels should be considered as a standard for the possibility of IgG4-RD. The differential diagnosis of multicentric Castleman's diseases and IgG4-RD should be also considered. Conclusions: Infiltration of plasma cells and IgG4-positive plasma cells may be detected in some types of lymphadenopathies and lymphomas in clinicopathological daily practice, but not all of them are related to IgG4-RD. It should be emphasized that the characteristics of plasma cell infiltration and the ratio of IgG4/IgG (>40%) should be considered for further differential diagnosis and avoiding misclassification of lymphadenopathies.
Humans ; Castleman Disease/pathology* ; Plasma Cells/pathology* ; Immunoglobulin G4-Related Disease ; China ; Lymphadenopathy/pathology* ; Inflammation/pathology* ; Lymph Nodes/pathology* ; Diagnosis, Differential ; Lymphadenitis/pathology* ; Immunoglobulin G/metabolism*

Humans ; Cholangitis, Sclerosing/diagnosis* ; Immunoglobulin G ; Hormones ; Diagnosis, Differential ; Autoimmune Diseases

Background: Though protective levels of neonatal SARS-CoV2 IgG still warrant further studies, maternal antibodies from COVID-19 vaccination may be the key to neonatal protection against COVID-19 related complications. This study aimed to correlate SARS-CoV2 IgG titers of term newborns delivered to fully vaccinated/boosted mothers with the time of dose completion to delivery and the type of COVID-19 vaccine received by the mothers. Methodology: A single center prospective cohort study that utilized CLIA Anti-S-RBD IgG determination in cord blood was done. Kruskal-Wallis and Mann-Whitney U Test were used to determine significant differences between IgG titers from vaccine types and groups as to trimester when COVID-19 dose was completed. Spearman’s rank was used to determine the correlation between IgG levels and interval of dose completion to delivery. Results: All 177 newborns enrolled in the study had reactive results (> 1 AU/ml) regardless of vaccine type received and trimester of maternal vaccination completion. The highest titers recorded per group was 19,340 AU/ml from the booster group and 5,960 AU/ml from the primary series group. The mRNA vaccinated group exhibited higher titers compared to other vaccine types regardless of the trimester completion for both groups. Conclusions A significant difference between IgG levels showed that higher titers were noted in the booster group compared to the primary series group across all trimesters. There was also a significant correlation between titer levels and time of dose completion to delivery with higher titers associated with more recent dose completion for both groups.
Immunoglobulin G ; COVID-19 Vaccines ; Infant, Newborn

OBJECTIVES: To study the effect of breastfeeding on immune function in infants with human cytomegalovirus (HCMV) infection. METHODS: A retrospective analysis was performed on the medical data of 135 infants with HCMV infection who were admitted to Children's Hospital Affiliated to Zhengzhou University from January 2021 to May 2022, and all these infants received breastfeeding. According to the results of breast milk HCMV-DNA testing, the infants were divided into two groups: breast milk HCMV positive (n=78) and breast milk HCMV negative (n=57). According to the median breast milk HCMV-DNA load, the infants in the breast milk HCMV positive group were further divided into two subgroups: high viral load and low viral load (n=39 each). Related indicators were compared between the breast milk positive and negative HCMV groups and between the breast milk high viral load and low viral load subgroups, including the percentages of peripheral blood lymphocyte subsets (CD3⁺ T cells, CD3⁺CD4⁺ T cells, CD3⁺CD8⁺ T cells, and CD19⁺ B cells), CD4⁺/CD8⁺ ratio, IgG, IgM, IgA, and urine HCMV-DNA load. RESULTS: There were no significant differences in the percentages of CD3⁺ T cells, CD3⁺CD4⁺ T cells, CD3⁺CD8⁺ T cells, and CD19⁺ B cells, CD4⁺/CD8⁺ ratio, IgG, IgM, IgA, and urine HCMV-DNA load between the breast milk HCMV positive and HCMV negative groups, as well as between the breast milk high viral load and low viral load subgroups (P>0.05). CONCLUSIONS Breastfeeding with HCMV does not affect the immune function of infants with HCMV infection.
Female ; Child ; Humans ; Infant ; Breast Feeding ; Cytomegalovirus Infections ; CD8-Positive T-Lymphocytes ; Retrospective Studies ; Infectious Disease Transmission, Vertical ; Milk, Human ; Cytomegalovirus ; Immunity ; Immunoglobulin A ; Immunoglobulin G ; Immunoglobulin M