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

The humoral immune response of B cells is the key to the protection of specific immunity, and immune aging reshapes its production and function. The decreased B cell immune function is an indicator of immune senescence. The impaired humoral immune function mediated by antibody secreted by B cells leads to a decline in the response of elderly individuals to the vaccine. These people are therefore more susceptible to infection and deterioration, and have a higher incidence of tumors and metabolic diseases. Activation-induced cytidine deaminase (AID) is an enzyme that triggers immunoglobulin class conversion recombination (CSR) and somatic high frequency mutation (SHM). It decreases during immune senescence and is considered to be a biomarker of decreased B cell function in aging mice and humans. Understanding the inherent defects of B-cell immune senescence and the regulation mechanism of AID in the aging process can provide new research ideas for the susceptibility, prevention and treatment of diseases in the elderly.
Animals ; Humans ; Mice ; Aging/metabolism* ; B-Lymphocytes/metabolism* ; Cytidine Deaminase/metabolism* ; Somatic Hypermutation, Immunoglobulin

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*

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*

OBJECTIVES: To investigate the change in the distribution of memory B cell subsets in children with frequently relapsing nephrotic syndrome (FRNS) during the course of the disease. METHODS: A total of 35 children with primary nephrotic syndrome (PNS) who attended the Department of Pediatrics of the Affiliated Hospital of Xuzhou Medical University from October 2020 to October 2021 were enrolled as subjects in this prospective study. According to the response to glucocorticoid (GC) therapy and frequency of recurrence, the children were divided into two groups: FRNS (n=20) and non-FRNS (NFRNS; n=15). Fifteen children who underwent physical examination were enrolled as the control group. The change in memory B cells after GC therapy was compared between groups, and its correlation with clinical indicators was analyzed. RESULTS: Before treatment, the FRNS and NFRNS groups had significantly increased percentages of total B cells, total memory B cells, IgD⁺ memory B cells, and IgE⁺ memory B cells compared with the control group, and the FRNS group had significantly greater increases than the NFRNS group (P<0.05); the FRNS group had a significantly lower percentage of class-switched memory B cells than the NFRNS and control groups (P<0.05). After treatment, the FRNS and NFRNS groups had significant reductions in the percentages of total B cells, total memory B cells, IgM⁺IgD⁺ memory B cells, IgM⁺ memory B cells, IgE⁺ memory B cells, IgD⁺ memory B cells, and IgG⁺ memory B cells (P<0.05) and a significant increase in the percentage of class-switched memory B cells (P<0.05). The FRNS group had a significantly higher urinary protein quantification than the NFRNS and control groups (P<0.05) and a significantly lower level of albumin than the control group (P<0.05). In the FRNS group, urinary protein quantification was negatively correlated with the percentage of class-switched memory B cells and was positively correlated with the percentage of IgE⁺ memory B cells (P<0.05). CONCLUSIONS Abnormal distribution of memory B cell subsets may be observed in children with FRNS, and the percentages of IgE⁺ memory B cells and class-switched memory B cells can be used as positive and negative correlation factors for predicting recurrence after GC therapy in these children.
Child ; Humans ; B-Lymphocyte Subsets/metabolism* ; Immunoglobulin E ; Immunoglobulin M ; Nephrotic Syndrome/immunology* ; Prospective Studies ; Glucocorticoids/therapeutic use*

Lectins are proteins responsible for recognizing the signals of sugar molecules in the body. Sialic acid-binding immunoglobulin-like lectins (Siglecs) regulate the innate and adaptive immune responses in the tumor microenvironment by recognizing the glycan structure containing sialic acid and mediating downstream signals through immune receptor tyrosine inhibitory motifs. In recent years, a variety of tumor treatment strategies targeting the sialic acid-Siglecs axis have been introduced, including sialoglycoprotein-mediated drug delivery and antibody mediated inhibition of Siglecs from recognizing tumor surface ligands. In the future, by combining with glycoprotein nanotherapy, antibody therapy and gene therapy, Siglecs can be used to accurately locate tumor targets and release the anti-tumor immunity, so as to achieve the purpose of effective cure of tumors.
Sialic Acid Binding Immunoglobulin-like Lectins/metabolism* ; N-Acetylneuraminic Acid ; Immunoglobulins/metabolism* ; Receptors, Immunologic ; Ligands

Single chain antibody fragment (scFv) is a small molecule composed of a variable region of heavy chain (VH) and a variable region of light chain (VL) of an antibody, and these two chains are connected by a flexible short peptide. scFv is the smallest functional fragment with complete antigen-binding activity, which contains both the antibody-recognizing site and the antigen-binding site. Compared with other antibodies, scFv has the advantages of small molecular weight, strong penetration, low immunogenicity, and easy expression. Currently, the most commonly used display systems for scFv mainly include the phage display system, ribosome display system, mRNA display system, yeast cell surface display system and mammalian cell display system. In recent years, with the development of scFv in the field of medicine, biology, and food safety, they have also attracted much attention in the sectors of biosynthesis and applied research. This review summarizes the advances of scFv display systems in recent years in order to facilitate scFv screening and application.
Animals ; Immunoglobulin Variable Region/genetics* ; Immunoglobulin Fragments/metabolism* ; Single-Chain Antibodies/metabolism* ; Peptide Library ; Mammals/genetics*

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*

Urticaria is an immune-mediated allergic disease. This study explored the effect of Jingfang Mixture on spleen T lymphocyte subsets of urticaria mice. A total of 50 Kunming mice were randomized into normal group(C), model group(V), and low-(JF-L, 0.5 g·kg~(-1)), medium-(JF-M, 1 g·kg~(-1)) and high-dose(JF-H, 2 g·kg~(-1)) Jingfang Mixture groups, with 10 mice in each group. The mixture of ovalbumin and aluminum hydroxide(0.1 mg + 0.1 mL) was used(intraperitoneal injection) to induce urticaria in mice. The administration began 6 days after the first immunization, and the second immunization was carried out 10 days after the first immunization. The pruritus index was detected within 30 min after the second immunization. The administration lasted 21 days. After 21 days, the serum was taken to detect the total IgE level. Based on hematoxylin and eosin(HE) staining, the pathological changes of skin tissue were observed, and Western blot was used to detect the levels of p-Janus kinase 2(JAK2)/JAK2 and p-signal transducer and activator of transcription 3(STAT3)/STAT3 in skin tissue. The spleen was taken to detect the spleen index, and flow cytometry was employed to determine the expression of lymphocyte subsets. The results showed that group V had obvious pathological changes in skin tissue compared with group C. Moreover, group V showed more scratches, higher spleen index, and higher level of total serum IgE than group C. In addition, higher levels of p-JAK2 and p-STAT3, lower proportions of CD4~+T, Th1, and Treg, higher proportions of CD8~+T, Th2, and Th17, and lower ratios of CD4~+/CD8~+, Th1/Th2, and Terg/Th17 were observed in group V than in group C. Compared with group V, each administration group showed alleviation of the pathological morphology of skin tissue, obvious epidermal thickening, relatively intact collagen fiber structure of dermal reticular layer, alleviated edema, and relief of vasodilation and peripheral inflammatory cell infiltration. Moreover, less scratching, lower spleen index, lower p-JAK2/JAK2 and p-STAT3/STAT3 were observed in the administration groups than in group V. JF-M group and JF-H group demonstrated lower levels of total IgE, larger proportions of CD4~+T, Th1, and Treg, smaller proportions of CD8~+ T, Th2, and Th17, and higher ratios of CD4~+/CD8~+, Th1/Th2, and Terg/Th17. In conclusion, Jingfang Mixture may improve the symptoms of urticaria mice by regulating the balance of spleen T lymphocyte subsets through JAK2-STAT3 signaling pathway.
Mice ; Animals ; Janus Kinase 2/pharmacology* ; Spleen ; T-Lymphocyte Subsets/metabolism* ; Signal Transduction ; Urticaria ; Immunoglobulin E