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: To investigate the role of multiple serological methods in the identification of complex antibodies. METHODS: The blood group antigens were detected by saline and microcolumn agglutination methods. The saline method was used to screen and identify IgM-type antibodies in the patient's serum, while the polybrene, anti-globulin, microcolumn agglutination, enzymic and absorption-elution methods were used to screen and identify IgG-type antibodies. RESULTS: The patient was B/CCDee/Jk(a-b+)/Fy(a-b+) blood type. The serum reacted with panel cells, and the reaction presented anti-E pattern in the saline medium. It was fully positive in the microcolumn agglutination card, except 2 negative ones after using papain to treat the panel cells. Referring to the pattern table, it was concluded that there existed anti-c, anti-E, and anti-Jk^a antibodies, and one antibody corresponding to an antigen that was easily destroyed by papain. The red blood cells with specific phenotype were selected for absorption-elution to identify IgG-type anti-c, anti-E, anti-Jk^a and anti-Fy^a antibodies. CONCLUSION It is confirmed that IgM-type anti-E, and IgG-type anti-c, anti-E, anti-Jk^a and anti-Fy^a antibodies exist in the patient's serum by multiple serological methods.
Humans ; Papain ; Blood Group Antigens ; Erythrocytes ; Immunoglobulin G ; Immunoglobulin M

Adult ; Female ; Hepatitis ; blood ; Humans ; Immunoglobulin G ; blood

OBJECTIVETo study the possible role of human β-defensins 1 (Hbd-1) and immunoglobulins A, G and M (IgA, IgG and IgM) in the development of recurrent pneumonia by measuring serum concentrations of the above indexes in infants with recurrent pneumonia and healthy infants.

METHODSSerum samples were obtained from 35 healthy children and 35 children aged from 2 to 24 months with recurrent pneumonia. Serum Hbd-1 concentration was measured using ELISA. Serum IgA, IgG and IgM concentrations were measured by immunonephelometry. The correlation of hBD-1 with IgA, IgG and IgM was evaluated.

RESULTSThe serum concentration of hBD-1 in infants with recurrent pneumonia (14±11 μg/mL) was significantly lower than in controls (18±11 μg/mL) (P<0.05), as was the serum concentration of IgA in infants with recurrent pneumonia (1.3±0.6 g/L vs 1.5±0.8 g/L; P<0.05). The serum concentration of IgG in infants with recurrent pneumonia was also significantly lower than in controls (9±3 g/L vs 13±5 g/L; P<0.05). There were no linear relationships between serum Hbd-1 and IgA, IgG and IgM (P>0.05).

CONCLUSIONSThe serum levels of hBD-1, IgA and IgG decrease in infants with recurrent pneumonia, suggesting disorders in the immune defensive function of the respiratory tract, and this may be one of the immunity related reasons for recurrent pneumonia in infants. It is of great clinical value to measure serum levels of Hbd-1, IgA, IgG and IgM in infants with recurrent pneumonia.

Female ; Humans ; Immunoglobulin A ; blood ; Immunoglobulin G ; blood ; Immunoglobulin M ; blood ; Immunoglobulins ; blood ; Infant ; Male ; Pneumonia ; immunology ; Recurrence ; beta-Defensins ; blood

The changes in serum levels of immunoglobulins G, M and A of dairy and beef calves of well-managed herds were monitored from birth to 14 days post partum using single radial immunodiffusion. Serum levels of all three immunoglobulin classes reached its peak at 24 hours in both groups of calves after birth, at which time there were very high levels of each immunoglobulin present. The mean IgM and IgA levels of the two groups became same at 6 days and 8 days of age, respectively but the mean IgG level of beef calves was approximately twice that of dairy calves throughout the experiment.
Animals ; Animals, Newborn ; Cattle/*immunology ; Female ; Immunodiffusion/veterinary ; Immunoglobulin A/blood ; Immunoglobulin G/blood ; Immunoglobulin M/blood ; Immunoglobulins/*blood ; Male ; Pregnancy

Objective: To summarize changes of serum immunoglobulin levels before and after chemotherapy in children with Burkitt lymphoma (BL), so as to investigate the effects of chemotherapy and rituximab on serum immunoglobulin levels in children with BL. Methods: Clinical data of 223 children with newly diagnosed Burkitt lymphoma at Beijing Children's Hospital from January 2009 to April 2017 were analyzed retrospectively. They were treated according to the modified LMB 89 regimen and some of them received combined rituximab therapy during the chemotherapy. The serum immunoglobulin (IgA, IgM, IgG) before chemotherapy, at the time of discontinuing chemotherapy, as well as 6, 12, 24, 36 months after chemotherapy were collected. Changes of serum IgA, IgM and IgG with time among different treatment groups were compared using repeated measures ANOVA. Results: According to risk group, 223 children were devided into group B（n=53）and group C（n=170）. Before chemotherapy, 109 cases (48.9%) were combined with hypogammaglobulinemia. The serum IgA, IgM, and IgG levels of all the patients were (0.9±0.7), 1.2 (0.5, 1.3) and (7.2±2.9) g/L before chemotherapy, (0.5±0.4), 0.2 (0.1, 0.3) and (6.3±2.3) g/L at the time of discontinuing chemotherapy (t=13.63, Z=-11.99, t=4.57, all P<0.05). There were statistical difference in IgA, IgM levels of group B and IgA, IgM, IgG levels of group C before chemotherapy and at the time of discontinuing chemotherapy (t=8.86, Z=-6.28, t=11.19, Z=-10.15, t=4.50, all P<0.05). The differences of serum IgA and IgG levels at the time after chemotherapy among patients treated with chemotherapy alone and those treated with chemotherapy combined rituximab in group B and C were significant (F=5.38, P=0.002 and F=4.22, P=0.007). Conclusions: Approximately half of children with BL have already existed hypogammaglobulinemia at initial diagnosis prior to the start of treatment. The modified LMB 89 regimen have significant effect on humoral immunity of children with BL. In the process of immune reconstruction after chemotherapy, rituximab has more significant effect on serum IgA and IgG levels in BL patients.
Agammaglobulinemia ; Burkitt Lymphoma/drug therapy* ; Child ; Humans ; Immunoglobulin A/blood* ; Immunoglobulin G/blood* ; Immunoglobulin M/blood* ; Retrospective Studies ; Rituximab/therapeutic use*

Pseudothrombocytopenia is an in vitro phenomenon usually associated with anticoagulant (ethylene diaminetetraacetic acid, EDTA)-dependent IgG platelet agglutinins. Two cases of pseudothrombocytopenia due to EDTA-independent agglutinins are reported. The fingerstick blood smear showed platelet clumping as well as EDTA, citrate and heparin samples. In a case with malaria, serum IgM was 985 mg/dL and serum protein immunofixation demonstrated an additional IgM band which disappeared together with platelet clumping a month later. The increased immunoglobulin (especially, IgM) appeared to be associated with platelet agglutinin. Another case had cold reactive agglutinin because the electronic platelet counts were dependent on temperature. These cases illustrate that pseudothrombocytopenia may be caused by more than one type of agglutinin and can be confirmed by using a direct fingerstick, keeping the sample warm, or drawing the blood into another anticoagulant.
Agglutinins* ; Blood Platelets ; Citric Acid ; Edetic Acid ; Heparin ; Immunoglobulin G ; Immunoglobulin M ; Immunoglobulins ; Malaria ; Platelet Count

Adolescent ; Arthritis, Juvenile ; blood ; immunology ; pathology ; Child ; Child, Preschool ; Female ; Humans ; Immunoglobulin A ; blood ; Immunoglobulin G ; blood ; Immunoglobulin M ; blood ; Interferon-gamma ; blood ; Interleukin-4 ; blood ; Male

OBJECTIVEThe development of recurrent respiratory tract infection (RRTI) is related to vitamin A deficiency and immune function abnormality in children. This study examined serum levels of IgG subclasses and vitamin A in children with recurrent respiratory tract infection.

METHODSSerum IgG subclasses levels (IgG1, IgG2, IgG3, IgG4) were detected using ELISA and serum vitamin A levels were detected using high performance liquid chromatography-Miller method in 80 children with RRTI (ranged from 2-10 years old). The values were compared with those from 80 aged-matched healthy children.

RESULTSSerum levels of IgG2 (1.52 +/- 0.18 g/L) and IgG4 (0.22 +/- 0.12 g/L) in children with RRTI were significantly lower than controls (IgG2: 2.23 +/- 0.08 g/L; IgG4: 0.28 +/- 0.01 g/L) (P < 0.05). Serum vitamin A levels in children with RRTI were also significantly lower than controls (1.16 +/- 0.22 micromol/L vs 1.56 +/- 0.12 micromol/L; P < 0.05). IgG2 and IgG4 deficiency (27%) was the most common in 22 RRTI children with vitamin A deficiency.

CONCLUSIONSSerum levels of IgG subclasses, IgG2 and IgG4, and vitamin A decrease in children with RRTI. There might be some relationship between the decreased IgG2 and IgG4 levels and vitamin A deficiency.

Child ; Child, Preschool ; Female ; Humans ; Immunoglobulin G ; blood ; classification ; Male ; Respiratory Tract Infections ; blood ; Vitamin A ; blood

OBJECTIVE: To establish a based method flow cytometry to identify the antigen Jka in human red blood cells (RBCs) and verify its accuracy. METHODS: A total of 96 blood samples were enrolled in the study randomly from the voluntary blood donors in Shenzhen Blood Center. The RBCs were incubated with IgG anti-Jka primary antibody, and then labeled with the secondary antibody anti-IgG-Alexa Fluor 647. The fluorescence histograms of each sample were obtained by flow cytometry. Serological agglutination test was used to compare the accuracy of flow cytometry in the detecting of antigen Jka, while PCR-SSP and gene sequencing genotyping were used to verify the accuracy of flow cytometry in the detecting of the antigen in human RBCs. RESULTS: The results of flow cytometry for antigen Jka in human RBCs were consistent with those from serological tests. Samples that demonstrated higher serological agglutination intensity also showed higher fluorescence activity, which indicate more stronger of Jka antigen. The sensitivity of flow cytometry was higher than that of serological test; especially in distinguish Jka weak and negative samples. Flow cytometric results of all samples were consistent with the genotyping results, which confirmed the accuracy of flow cytometry. CONCLUSION The study established a new flow cytometry-based method successfully for the identification of Jka antigen of Kidd blood group in human RBCs. The Kidd blood group antigen Jka of different intensities can be accurately distinguished by the technique.
Blood Group Antigens ; Blood Grouping and Crossmatching ; Erythrocytes ; Flow Cytometry ; Humans ; Immunoglobulin G ; Kidd Blood-Group System