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*

Humans ; Child ; Immunoglobulin G ; Autoimmune Diseases ; Hepatitis, Autoimmune ; Pancreatic Diseases ; Pancreatic Neoplasms

Objective: To analyze the clinical characteristics of children with multisystem inflammatory syndrome (MIS-C) associated with SARS-CoV-2 in China, and to improve the understanding of MIS-C among pediatricians. Methods: Case series study.Collect the clinical characteristics, auxiliary examinations, treatment decisions, and prognosis of 64 patients with MIS-C from 9 hospitals in China from December 2022 to June 2023. Results: Among the 64 MIS-C patients, 36 were boys and 28 were girls, with an onset age being 2.8 (0.3, 14.0) years. All patients suffered from fever, elevated inflammatory indicators, and multiple system involvement. Forty-three patients (67%) were involved in more than 3 systems simultaneously, including skin mucosa 60 cases (94%), blood system 52 cases (89%), circulatory system 54 cases (84%), digestive system 48 cases (75%), and nervous system 24 cases (37%). Common mucocutaneous lesions included rash 54 cases (84%) and conjunctival congestion and (or) lip flushing 45 cases (70%). Hematological abnormalities consisted of coagulation dysfunction 48 cases (75%), thrombocytopenia 9 cases (14%), and lymphopenia 8 cases (13%). Cardiovascular lesions mainly affected cardiac function, of which 11 patients (17%) were accompanied by hypotension or shock, and 7 patients (12%) had coronary artery dilatation.Thirty-six patients (56%) had gastrointestinal symptoms, 23 patients (36%) had neurological symptoms. Forty-five patients (70%) received the initial treatment of intravenous immunoglobulin in combination with glucocorticoids, 5 patients (8%) received the methylprednisolone pulse therapy and 2 patients (3%) treated with biological agents, 7 patients with coronary artery dilation all returned to normal within 6 months. Conclusions: MIS-C patients are mainly characterized by fever, high inflammatory response, and multiple organ damage. The preferred initial treatment is intravenous immunoglobulin combined with glucocorticoids. All patients have a good prognosis.
Male ; Child ; Female ; Humans ; Immunoglobulins, Intravenous/therapeutic use* ; Blood Coagulation ; COVID-19 ; China/epidemiology* ; Connective Tissue Diseases ; Coronary Aneurysm ; Fever ; Systemic Inflammatory Response Syndrome/therapy*

Objective: To evaluate the association between immunoglobulin concentration and the risk of type 2 diabetes mellitus (T2DM) in adults in Tianjin City. Methods: Based on the Tianjin Chronic Low-grade Systemic Inflammation and Health (TCLSIHealth) cohort from January 2010 to December 2018, subjects who had completed the measurement of baseline immunoglobulin concentration and blood glucose concentration and not been diagnosed with any type of diabetes at baseline were selected in this study. The collected data included the concentration of serum immunoglobulin (IgG, IgM, IgA and IgE), fasting blood glucose and other potential confounders. The subjects were divided into four groups from Q₁ to Q₄ according to the quartiles of baseline immunoglobulin concentration. The multivariable Cox regression model was used to assess the association between the baseline immunoglobulin concentration and T2DM. Results: A total of 6 315 subjects aged (50.1±10.0) years were included. About 390 subjects were newly diagnosed with T2DM during the follow-up period. The incidence rate was 16.8/1 000 person-years. After adjusting for age, sex, waist circumference, smoking status, drinking status, eosinophil ratio, metabolic syndrome, first-or second-degree family history, and reciprocal adjusting for other immunoglobulin concentrations, compared to the lowest quartile concentration group Q₁, subjects in group Q₄ with the highest quartile of IgG concentration showed a lower risk of T2DM (HR=0.71, 95%CI: 0.52-0.97), and subjects in group Q₄ with the highest quartile of IgM concentration also had a decreased risk of T2DM (HR=0.66, 95%CI: 0.47-0.91). Subjects in group Q₄ with the highest quartile of IgA concentration had an increased risk of T2DM (HR=1.56, 95%CI: 1.18-2.07). The risk of T2DM decreased with the increase of serum IgG and IgM concentrations (P_trend=0.018, P_trend=0.010) and increased with the increase of serum IgA concentrations (P_trend<0.001). No association was found between the concentration of IgE and T2DM risk (HR=0.99, 95%CI: 0.74-1.31, P_trend=0.891). Conclusion: The concentration of IgG and IgM is negatively associated with the risk of T2DM, and the concentration of IgA is positively associated with the risk of T2DM in Tianjin City. The concentrations of IgG, IgM and IgA could be a predictor of hyperglycemia and T2DM.
Humans ; Adult ; Diabetes Mellitus, Type 2 ; Prospective Studies ; Blood Glucose ; Inflammation/complications* ; Immunoglobulin A ; Immunoglobulin M ; Immunoglobulin G ; Immunoglobulin E ; Risk Factors

Objective: To analyze the immunological characteristics and antibody changes of patients infected with the Omicron BA.1 and evaluate the possibility of secondary infection. Methods: A total of 104 patients infected with Omicron BA.1 in the Jinnan District of Tianjin from January 8 to February 2, 2022, were included in the study. The control group and case group were matched 1∶1 based on age, sex and vaccination status. Serum was collected from the case group and control group at 3, 6 and 9 months after infection. The serum levels of interleukin4 (IL-4), IL-5 and interferon-gamma (IFN-γ), as well as the positive rates of IgG, IgG1 and IgG2, were detected by ELISA. Results: The highest concentration of IFN-γ in the case group at 6 months after infection was 145.4 pg/ml, followed by a decrease in concentration. The concentrations of IL-4 and IL-5 began to decrease at 6 months after infection (all P<0.001). There was no significant difference in the IgG2 positive rate between the case group and the control group at 6 months after BA.1 infection. However, at 9 months, there was a significant decrease compared to the control group (P=0.003). The ratio of IFN-γ/IL4 at 3 months after infection in the case group was lower than that in the control group (P<0.001). There was no significant difference in the ratio between the case group and the control group at 9 months after infection. Conclusion: The cellular immune function has been impaired at 3 months after infection with BA.1, and the specific cellular immune and humoral immune functions decrease significantly after 6 months, and the risk of secondary infection increases.
Adult ; Humans ; Immunity, Humoral ; Coinfection ; Interleukin-4 ; Interleukin-5 ; Immunoglobulin G ; Interferon-gamma

A study was conducted on rural women of childbearing age aged 20-49 who underwent the National Free Preconception Health Examination Project (NFPHEP)in Yunnan Province from 2013 to 2019. Descriptive analysis was conducted to determine the negative rate of IgG antibodies against the rubella virus and its differences among various socio-demographic characteristics. Among the 1 511 203 study subjects, the negative rate of IgG antibodies against the rubella virus was 24.36%. Only 2.64% of the population had received rubella virus vaccine. The negative rate of IgG antibodies among rural childbearing-age women in the preconception period in Yunnan Province decreased with age and educational level (P_trend<0.001). The negative rate of IgG antibodies in ethnic minority women of childbearing age in the preconception period (25.19%) was higher than that of Han women (23.88%). Among the 22 ethnic groups with over 1 000 participants, the negative rates of IgG antibodies in women of childbearing age from the Blang (32.85%), Bouyei (31.03%), Zhuang (31.01%), and Miao (30.70%) ethnic groups were higher than those of women from other ethnic groups. Among the 16 states (cities) in Yunnan Province, the negative rate of IgG antibodies in pregnant women of childbearing age in Wenshan Zhuang and Miao Autonomous Prefecture (38.06%) and Lincang City (32.63%) was higher than that in other states (cities). The negative rate of serum IgG antibodies in women who reported having received rubella virus vaccine (18.60%) was lower than that in other non-vaccinated populations (24.52%). The proportion of rural women of childbearing age in Yunnan Province who were susceptible to the rubella virus before pregnancy was still high. It is necessary to promote rubella vaccination among people susceptible to rubella, especially pregnant women, to prevent rubella virus infection and reduce the incidence rate and disease burden of rubella people.
Pregnancy ; Female ; Humans ; Rubella virus ; Immunoglobulin G ; Ethnicity ; Minority Groups ; China ; Rubella/prevention & control* ; Antigens, Viral ; Vaccines

Objective: To analyze the immunological characteristics and antibody changes of patients infected with the Omicron BA.1 and evaluate the possibility of secondary infection. Methods: A total of 104 patients infected with Omicron BA.1 in the Jinnan District of Tianjin from January 8 to February 2, 2022, were included in the study. The control group and case group were matched 1∶1 based on age, sex and vaccination status. Serum was collected from the case group and control group at 3, 6 and 9 months after infection. The serum levels of interleukin4 (IL-4), IL-5 and interferon-gamma (IFN-γ), as well as the positive rates of IgG, IgG1 and IgG2, were detected by ELISA. Results: The highest concentration of IFN-γ in the case group at 6 months after infection was 145.4 pg/ml, followed by a decrease in concentration. The concentrations of IL-4 and IL-5 began to decrease at 6 months after infection (all P<0.001). There was no significant difference in the IgG2 positive rate between the case group and the control group at 6 months after BA.1 infection. However, at 9 months, there was a significant decrease compared to the control group (P=0.003). The ratio of IFN-γ/IL4 at 3 months after infection in the case group was lower than that in the control group (P<0.001). There was no significant difference in the ratio between the case group and the control group at 9 months after infection. Conclusion: The cellular immune function has been impaired at 3 months after infection with BA.1, and the specific cellular immune and humoral immune functions decrease significantly after 6 months, and the risk of secondary infection increases.
Adult ; Humans ; Immunity, Humoral ; Coinfection ; Interleukin-4 ; Interleukin-5 ; Immunoglobulin G ; Interferon-gamma

A study was conducted on rural women of childbearing age aged 20-49 who underwent the National Free Preconception Health Examination Project (NFPHEP)in Yunnan Province from 2013 to 2019. Descriptive analysis was conducted to determine the negative rate of IgG antibodies against the rubella virus and its differences among various socio-demographic characteristics. Among the 1 511 203 study subjects, the negative rate of IgG antibodies against the rubella virus was 24.36%. Only 2.64% of the population had received rubella virus vaccine. The negative rate of IgG antibodies among rural childbearing-age women in the preconception period in Yunnan Province decreased with age and educational level (P_trend<0.001). The negative rate of IgG antibodies in ethnic minority women of childbearing age in the preconception period (25.19%) was higher than that of Han women (23.88%). Among the 22 ethnic groups with over 1 000 participants, the negative rates of IgG antibodies in women of childbearing age from the Blang (32.85%), Bouyei (31.03%), Zhuang (31.01%), and Miao (30.70%) ethnic groups were higher than those of women from other ethnic groups. Among the 16 states (cities) in Yunnan Province, the negative rate of IgG antibodies in pregnant women of childbearing age in Wenshan Zhuang and Miao Autonomous Prefecture (38.06%) and Lincang City (32.63%) was higher than that in other states (cities). The negative rate of serum IgG antibodies in women who reported having received rubella virus vaccine (18.60%) was lower than that in other non-vaccinated populations (24.52%). The proportion of rural women of childbearing age in Yunnan Province who were susceptible to the rubella virus before pregnancy was still high. It is necessary to promote rubella vaccination among people susceptible to rubella, especially pregnant women, to prevent rubella virus infection and reduce the incidence rate and disease burden of rubella people.
Pregnancy ; Female ; Humans ; Rubella virus ; Immunoglobulin G ; Ethnicity ; Minority Groups ; China ; Rubella/prevention & control* ; Antigens, Viral ; Vaccines

OBJECTIVE: To understand the medical treatment and clinical characteristics of patients with IgG4-related disease (IgG4-RD) with complex clinical manifestations and easy to be misdiagnosed and missed, and to improve the recognition of this disease among doctors from relevant medical departments. METHODS: A retrospective analysis was conducted on the medical records of patients diagnosed with IgG4-RD who were hospitalized and discharged from Peking University Third Hospital from January 1, 2012 to December 31, 2022. The patient' s medical visit status, clinical manifestations, laboratory examinations, diagnosis, and treatment information were summarized. RESULTS: A total of 116 patients diagnosed with IgG4-RD were included in this study, with a male to female ratio of 2. 52∶ 1 and an average age of (61.83±10.80) years. The departments for initial visits were gastroenterology, general surgery, and ophthalmology. While the departments responsible for definitive diagnosis were gastroenterology, rheumatology and immunology, and respiratory medicine. Twenty-one patients (18. 10%) required consultation and treatment from three or more departments before receiving a definitive diagnosis. The median time from symptom onset to the initial clinic visit was 2 (1, 7) months, and the median time from symptom onset to diagnosis was 1 (1, 12) month. Twenty-four patients (20.69%) underwent surgical resection of the affected sites before diagnosis. According to the classification criteria of IgG4-RD, sixty-eight (58.62%) cases were diagnosed definitively, eight (6.9%) cases were likely to be diagnosed, and 40 (34.48%) cases were suspected to be diagnosed. In the 68 definitively diagnosed patients, the most commonly affected organs were submandibular gland, the pancreas, biliary tract, parotid in sequence. The median serum IgG4 (IgG4, immunoglobulin G4) level was 6.16 (3. 61, 12. 30) g/L. Fifty-seven patients (83.82%) were treated with glucocorticoids, and 14 patients (20.59%) were treated with immunosuppressants. The use of immunosuppressants was mainly in the rheumatology and immunology department (78. 57%). CONCLUSION IgG4-RD is more common in elderly males, with submandibular gland, the pancreas, biliary tract, and parotid being most commonly affected. The distribution of initial visit departments in patients is wide. The proportion of definitive diagnosis based on pathology is relatively low. In terms of treatment, the main approach is steroid treatment, while the use of immunosuppres-sants is not widespread.
Humans ; Male ; Female ; Aged ; Middle Aged ; Immunoglobulin G4-Related Disease/diagnosis* ; Retrospective Studies ; Immunosuppressive Agents/therapeutic use* ; Glucocorticoids ; Immunoglobulin G

OBJECTIVE: To explore the clinical significance of anti-endothelial cell antibodies (AECA) in predicting early miscarriage. METHODS: A total of 122 pregnant women with no history of autoimmune diseases who underwent prenatal examination at Peking University People's Hospital from January 2020 to December 2022 were selected, and they were tested for AECA. Based on the history of early miscarriage (gestational age at miscarriage < 12 weeks), the participants were divided into an early miscarriage group and a control group. t-tests, non-parametric Wilcoxon tests, Chi-square tests, and Fisher's exact probability method were used to compare general information and laboratory indicators between the two groups. A multivariate Logistic regression model was used to analyze the factors associated with early miscarriage. The natural miscarriage rates were assessed through follow-up with pregnant women, and Kaplan-Meier survival analysis was employed to compare the natural miscarriage rates between AECA-positive and AECA-negative pregnant women. RESULTS: (1) A total of 122 pregnant women were enrolled, comprising 35 cases (28.7%) in the early miscarriage group, with an average age of (32.1±6.1) years, and 87 cases (71.3%) in the control group, with an average age of (30.7±5.1) years. The early miscarriage group had higher gravidity [3 (2, 4) vs. 1 (1, 2), Z=-6.402, P < 0.001] and a higher prevalence of hypertension (11.4% vs.1.1%, P=0.024). The positive rate of AECA in the early miscarriage group (34.3% vs. 8.0%, χ²=13.070, P < 0.001) and the proportion of elevated immunoglobulin G (17.1% vs. 4.6%, P=0.032) were significantly higher than that in the control group. (2) Multivariate logistic regression analysis showed that higher gravidity (OR=4.149, 95%CI: 2.287-7.529, P < 0.001), AECA positivity (OR= 4.288, 95% CI: 1.157-15.893, P=0.029), and elevated immunoglobulin G levels (OR =6.177, 95%CI: 1.156-33.015, P=0.033) were risk factors for early miscarriage. (3) The 122 pregnant women were categorized into two groups: the AECA-positive group (19 cases) and the AECA-negative group (103 cases). Survival analysis demonstrated that at the end of 12 weeks of gestation, the fetal survival rate in the AECA-positive group was significantly lower than that in the AECA-negative group (84.2% vs. 96.1%, P= 0.035). CONCLUSION Higher gravidity, AECA positivity, and elevated immunoglobulin G levels are significant risk factors for early miscarriage. The results demonstrate that AECA is a novel predicting test in early miscarriage.
Humans ; Female ; Pregnancy ; Adult ; Infant ; Abortion, Spontaneous ; Autoantibodies ; Immunoglobulin G ; Hypertension