Research on IgG4-related disease (IgG4-RD), an autoimmune condition recognized to be a unique disease entity only two decades ago, has processed from describing patients' symptoms and signs to summarizing its critical pathological features, and further to investigating key pathogenic mechanisms. Challenges in gaining a better understanding of the disease, however, stem from its relative rarity-potentially attributed to underrecognition-and the absence of ideal experimental animal models. Recently, with the development of various high-throughput techniques, "omics" studies at different levels (particularly the single-cell omics) have shown promise in providing detailed molecular features of IgG4-RD. While, the application of omics approaches in IgG4-RD is still at an early stage. In this paper, we review the current progress of omics research in IgG4-RD and discuss the value of machine learning methods in analyzing the data with high dimensionality.
Humans ; Immunoglobulin G4-Related Disease/metabolism* ; Immunoglobulin G/metabolism* ; Machine Learning ; Animals ; Proteomics/methods*

OBJECTIVES: This study aimed to explore the therapeutic effect and mechanism of ginsenoside Rb3 on experimental periodontitis and bone resorption in rats. METHODS: Male SD rats were randomly divided into a control group, a ligation group, an Rb3 group, and a doxycycline (Dox) group for in vivo experiments. A periodontitis model was established by ligating the maxillary second molar, and samples were collected after 3 weeks of drug treatment. Micro-CT assessment of alveolar bone resorption was performed, and hematoxylin-eosin (HE) staining was used to observe pathological changes in periodontal and visceral tissues. Tartrate resistant acid phosphatase (TRAP) staining was applied to detect the formation of osteoclasts in periodontal tissues, and enzyme-linked immunosorbent assay (ELISA) was adopted to detect the serum levels of interleukin (IL)-6, IL-8, immunoglobulin (Ig)M, and IgG. Quantitative polymerase chain reaction (qPCR) was employed to detect the expression of factors related to gingival inflammation and osteoclast formation. Immunofluorescence staining was used to detect phospho-extracellular signal-regulated kinase (p-ERK) expression. In vitro experiments were conducted by pretreating RAW264.7 cells with drugs and adding lipopolysaccharides (LPS) stimulation from Porphyromonas gingivalis (P. gingivalis). IL-1β and IL-6 mRNA expression was detected by qPCR, and Western blot was used to detect the effect of Rb3 on the mitogen-activated protein kinases (MAPKs) signaling pathway. RESULTS: Compared with the control group, the ligation group showed significant periodontitis and bone resorption. Compared with the ligation group, the Rb3 group showed a decrease in alveolar bone resorption and osteoclast formation; p-ERK/ERK ratio, IL-1β, IL-6, and nuclear factor of activated T cells (NFATc1) mRNA levels and downstream gene expression in periodontal tissues; serum IL-6, IL-8, IgG, and IgM levels. Rb3 reduced IL-8 and IL-1β mRNA expression levels and p-ERK/ERK and p-p38 MAPK/p38 MAPK ratios in RAW264.7 cells induced by P. gingivalis LPS stimulation. CONCLUSIONS Rb3 inhibits inflammation and bone resorption in experimental periodontitis in rats. Compared with Dox, Rb3 has better effects in inhibiting pro-inflammatory factors and osteoclast gene expression and may exert anti-inflammatory effects by activating the MAPK signaling pathway.
Animals ; Ginsenosides/therapeutic use* ; Rats, Sprague-Dawley ; Male ; Periodontitis/pathology* ; Rats ; Osteoclasts/drug effects* ; Interleukin-1beta/metabolism* ; Interleukin-6/blood* ; Mice ; Alveolar Bone Loss ; Interleukin-8/blood* ; Immunoglobulin G/blood* ; RAW 264.7 Cells ; Transcription Factors

In this study, we constructed a series of recombinant Fc variants of immunoglobulin G4 (IgG4), screened the fragment crystallizable (Fc) variants with significantly prolonged serum half-lives, and analyzed the relationship between mutation site and half-life, aiming to provide a theoretical basis for the development of IgG4 antibodies and Fc fusion protein-based drugs. Nine gene sites were selected for mutation, and different mutation sites were combined. The variant expression plasmids pET24b-Fc were constructed by molecular cloning and point mutation. The plasmids were transformed into Escherichia coli BL21(DE3) for the expression of different recombinant proteins of Fc. Fc2 and Fc3 variants had slightly lower recombinant protein yields, and the expression of other variants was not affected. The toxicity of different Fc variants was determined by cell counting kit-8 (CCK-8) and calcein acetoxymethyl ester/ propidium iodide (calcein AM/PI) in vitro and enzyme-linked immuno sorbent assay (ELISA) in vivo. The results showed that the recombinant Fc variants had good biocompatibility and safety. Finally, the Fc variants were labeled with fluorescent markers, and the effects of different mutations on their serum half-lives were investigated by in vivo experiments. The Fc5 variant with prolonged serum half-life was successfully screened out, which provided a theoretical and practical basis for the optimal design of IgG4 subtype antibody and Fc fusion protein drugs.
Immunoglobulin G/blood* ; Immunoglobulin Fc Fragments/biosynthesis* ; Half-Life ; Animals ; Escherichia coli/metabolism* ; Humans ; Recombinant Fusion Proteins/biosynthesis* ; Recombinant Proteins/biosynthesis* ; Mice

This study aimed to investigate the mechanism by which Shegan Mahuang Decoction(SGMH) and its bitter Chinese herbs(BCHs) regulated the lung-gut axis through the bitter taste receptor 14(TAS2R14)/secretory immunoglobulin A(SIgA)/thymic stromal lymphopoietin(TSLP) to intervene in the epithelial cell barrier of cold asthma rats. Fifty SD rats were randomly divided into the following five groups: normal group, model group, dexamethasone group, SGMH group, and BCHs group. A 10% ovalbumin(OVA) solution was used to sensitize the rats via subcutaneous injection on both sides of the abdomen and groin, combined with 2% OVA atomization and cold(2-4 ℃) stimulation to induce a cold asthma model in rats. The SGMH, BCHs, and dexamethasone groups were given corresponding treatments by gavage and nebulization, while the normal and model groups received normal saline by gavage and nebulization. After the final stimulation, pathological changes in the lung and intestine tissues were observed using hematoxylin-eosin(HE) and periodic acid-Schiff(PAS) staining. Lung function was assessed by measuring the ratio of forced expiratory volume in the first second to forced vital capacity(FEV1/FVC), the ratio of the average flow rate at 25%-75% of forced vital capacity to foned vital capacity(FEV25%-75%/FVC), the peak expiratory flow(PEF), and pulmonary resistance(RL). The levels of IL-4, IL-5, IL-13, and TNF-α in serum, and sIgA in serum, intestinal, and bronchial mucosa were detected by enzyme-linked immunosorbent assay(ELISA). The expression of TAS2R14 protein in lung tissue was detected by Western blot(WB). The content of short-chain fatty acids(SCFAs) in rat feces was determined by gas chromatography-mass spectrometry(GC-MS). The effect of TAS2R14/TSLP on lipopolysaccharide(LPS)-induced inflammation in epithelial cells in the BCHs group was observed, and the expression of TAS2R14 and TSLP in cells was detected by WB. Compared with the normal group, the model group showed reduced water intake, diet, and body weight, increased infiltration of inflammatory cells in the lung and intestinal tissues, goblet cell hyperplasia, significantly decreased FEV1/FVC, FEV25%-75%/FVC, and PEF, and significantly increased RL. Moreover, serum levels of IL-4, IL-5, IL-13, and TNF-α were elevated, and sIgA levels in serum, intestine, and bronchial mucosa were significantly decreased. TAS2R14 expression in lung tissues was inhibited, and the content of acetic acid, propionic acid, and butyric acid in feces was significantly reduced. In the LPS group, TSLP expression increased, and TAS2R14 expression decreased. Compared with the model group, the general condition of rats in the SGMH and BCHs groups improved, with reduced infiltration of inflammatory cells and goblet cell hyperplasia in the lung and intestinal tissues. FEV1/FVC, FEV25%-75%/FVC, and PEF significantly increased, and RL significantly decreased. Serum levels of IL-4, IL-5, IL-13, and TNF-α decreased, while sIgA levels in serum, intestine, and bronchial mucosa significantly increased, and TAS2R14 expression was activated in lung and intestinal tissues. The content of acetic acid, propionic acid, and butyric acid in feces significantly increased. Compared with the model group, the BCHs group and the agonist group showed inhibited TSLP expression and increased TAS2R14 expression. The results showed that both SGMH and BCHs could reduce lung and intestinal inflammatory reactions, improve lung function, and regulate the content of intestinal SCFAs in asthmatic rats. There was no significant difference in TAS2R14 protein expression between the SGMH and BCHs groups, indicating that the clinical efficacy of BCHs may be related to the activation of the bitter receptor TAS2R14 and the regulation of immune inflammatory mediators in lung and intestinal epithelial cells.
Animals ; Drugs, Chinese Herbal/administration & dosage* ; Rats ; Rats, Sprague-Dawley ; Lung/metabolism* ; Asthma/metabolism* ; Cytokines/immunology* ; Male ; Receptors, G-Protein-Coupled/immunology* ; Epithelial Cells/metabolism* ; Thymic Stromal Lymphopoietin ; Immunoglobulin A, Secretory/genetics* ; Humans ; Cold Temperature

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*

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

Immunoglobulin (IgG) glycosylation affects the effector functions of IgG in a myriad of biological processes and has been closely associated with numerous autoimmune diseases, including systemic lupus erythematosus (SLE), thus underlining the pathogenic role of glycosylation aberration in autoimmunity. This study aims to explore the relationship between IgG sialylation patterns and lupus pregnancy. Relative to that in serum samples from the control cohort, IgG sialylation level was aberrantly downregulated in serum samples from the SLE cohort at four stages (from preconception to the third trimester of pregnancy) and was significantly associated with lupus activity and fetal loss during lupus pregnancy. The type I interferon signature of pregnant patients with SLE was negatively correlated with the level of IgG sialylation. The lack of sialylation dampened the ability of IgG to suppress the functions of plasmacytoid dendritic cells (pDCs). RNA-seq analysis further revealed that the expression of genes associated with the spleen tyrosine kinase (SYK) signaling pathway significantly differed between IgG- and deSia-IgG-treated pDCs. This finding was confirmed by the attenuation of the ability to phosphorylate SYK and BLNK in deSia-IgG. Finally, the coculture of pDCs isolated from pregnant patients with SLE with IgG/deSia-IgG demonstrated the sialylation-dependent anti-inflammatory function of IgG. Our findings suggested that IgG influences lupus activity through regulating pDCs function via the modulation of the SYK pathway in a sialic acid-dependent manner.
Humans ; Pregnancy ; Female ; Lupus Erythematosus, Systemic/pathology* ; Signal Transduction ; N-Acetylneuraminic Acid/metabolism* ; Immunoglobulin G ; Dendritic Cells/pathology*

Adult ; Aged ; Antibodies, Viral/metabolism* ; China ; Female ; Humans ; Immunoglobulin G/metabolism* ; Male ; Measles/metabolism* ; Measles virus/physiology* ; Medical Staff ; Middle Aged ; Saliva/virology* ; Young Adult

Objective: To assess the correlation of glomerular C1q or IgA deposition with clinical and pathological features of primary membranous nephropathy (PMN) in children. Methods: The clinical and pathological manifestations including (phospholipase A2 receptor, PLA2R) and IgG subclasses staining in renal biopsies, serum anti-PLA2R antibody and therapeutic response of 33 children diagnosed with PMN in Peking University First Hospital from December 2012 to December 2020 were retrospectively summarized and analyzed. According to results of PLA2R test and findings renal pathological, the patients were divided into PLA2R-related group and non-PLA2R-related group, typical MN group and atypical MN group, C1q deposit group and non-C1q deposit group, as well as IgA deposit group and non-IgA deposit group respectively. T-test, Mann-Whitney U test and Fisher's exact probability test were used for comparison between the groups. Results: Among the 33 children with PMN, there were 20 males and 13 females, of that the age of onset was 11 (8, 13) years, and 32 patients had nephrotic level proteinuria. Renal biopsies were performed at 4.6 (2.1, 11.6) months after onset, and 28 patients (85%) received glucocorticoid or immunosuppressive therapy prior to renal biopsy. There were 20 cases (61%) with PLA2R-related MN and 13 cases (39%) with non-PLA2R-related MN. Compared with the non-PLA2R-related group, the PLA2R-related group had an older age of onset (12 (10, 13) vs. 7 (3, 12) years, Z=-2.52, P=0.011), a lower preceding infection rate (45% (9/20) vs. 11/13, P=0.032) and lower spontaneous remission rate (0 vs. 4/13, P=0.017). Renal PLA2R positivity was significantly associated with predominant or co-deposition of IgG4 (13/17 vs. 5/15, P=0.031) and low albumin levels at renal biopsy ((25±6) vs. (29±7) g/L, t=2.14, P=0.041). There were 12 patients with typical PMN and 21 patients with atypical PMN, and no significant difference in clinical and pathological manifestations was found between these 2 groups (all P>0.05). There were 10 cases (32.3%) with glomerular C1q deposition, and their disease course before renal biopsy was significantly shorter than those without C1q deposition (1.8 (0.8, 5.9) vs. 6.0 (2.5, 22.3) months, Z=-2.27, P=0.023). Twelve cases (36.4%) had glomerular IgA deposition, and their course of disease,clinical and pathological manifestations were not significantly different from those without IgA deposition (all P>0.05). Conclusion: Glomerular C1q or IgA deposition may not affect the clinical manifestations, glomerular PLA2R and IgG subclasses staining pattern, or the response to treatment of PMN in children.
Autoantibodies ; Child ; Complement C1q/metabolism* ; Female ; Glomerulonephritis, Membranous/drug therapy* ; Humans ; Immunoglobulin A/immunology* ; Immunoglobulin G ; Kidney Glomerulus ; Male ; Retrospective Studies

Objective: To detect and analyze the expression level of serum 25-hydroxyvitamin D [25(OH)D], periodontal clinical indicators and immunological indicators of rheumatism in patients with periodontitis and rheumatoid arthritis (RA), and to explore the correlation between 25(OH)D and the two diseases. Methods: This study was a case-control study. According to the inclusion criteria, patients from the Department of Stomatology and the Department of Rheumatology and Immunology and healthy volunteers from the Physical Examination Center were selected from November 2018 to May 2019 in Shengjing Hospital, China Medical University respectively. The patients were divided into 4 groups: 26 patients with simple periodontitis were included in the periodontitis group; 23 patients with RA were included in the RA group; 22 patients with RA and periodontitis simultaneously were included in the RA with periodontitis group; 22 healthy volunteers were included in the healthy control group, adding up to a total of 93 cases. The general information and periodontal clinical indexes of subjects in these 4 groups were recorded. Median elbow venous blood samples were collected from fasting subjects in each group, and 25(OH)D and immunoglobulin (Ig) were measured. The disease activity scores of RA patients were recorded and the rheumatic immune indexes were determinated. Pearson correlation analysis was performed between 25 (OH) D level and periodontal indexes in subjects of 4 groups. Results: The expression levels of rheumatoid factor [106.5(47.1, 283.8) kU/L] and C-reactive protein [20.5(13.1, 32.3) mg/L] in RA with periodontitis group were significantly higher than those in RA group [60.1(19.0, 110.0) kU/L, 14.7(3.0, 18.0) mg/L] (Z=-2.29, P=0.022; Z=-2.25, P=0.024). The levels of IgG and IgA in RA with periodontitis group [IgG and IgA: (16.0±4.3), (3.2± 1.3) g/L] as well as RA group [IgG and IgA: (16.3±5.5), (3.7±1.8) g/L] were significantly higher than those in healthy control group [IgG and IgA: (12.0±1.8), (2.3±0.6) g/L] and periodontitis group [IgG and IgA: (12.5±2.2), (2.0±0.7) g/L](P<0.05). The level of 25(OH)D in RA with periodontitis group [(26.0±9.8) nmol/L] was significantly lower than that in periodontitis group [(35.6±8.4) nmol/L] and RA group [(32.7±8.6) nmol/L] (P<0.05). The level of 25(OH)D was negatively correlated with sulcus bleeding index (r=-0.43, P=0.032) and clinical attachment loss (r=-0.41, P=0.043). Conclusions: Expression level of 25(OH)D was significantly decreased in patients with periodontitis and RA. There was a certain correlation between 25(OH)D and periodontitis and RA.
Arthritis, Rheumatoid/metabolism* ; Case-Control Studies ; Humans ; Immunoglobulin A ; Immunoglobulin G ; Periodontitis ; Vitamin D/analogs & derivatives*