Serological evaluation of immunity against Corynebacterium diphtheriae in the Peruvian adult population

Serum immunoglobulin levels in patients with neuroblastoma and their prognosis

The levels of correlation between the number of Opisthorchis viverrini eggs excreted in the faeces and levels of anti-Opisthorchis IgG and IgG(4) in the serum and urine (as indicated by absorbances in ELISA) have recently been evaluated in north-eastern Thailand. The 225 subjects investigated in detail, all of whom came from an endemic village in Chaiyaphum province, were selected on the basis of the numbers of O. viverrini eggs that they were excreting. ELISA based on a crude antigen extract of the trematode were then used to determine the levels of specific IgG and IgG(4) in serum and urine samples. Compared with the egg-negative, the villagers who were found to be egg-positive for O. viverrini had significantly higher levels of specific IgG in their urine and serum and significantly higher levels of specific IgG(4) in their serum. The serum levels of specific IgG and IgG(4) and the urine levels of specific IgG all correlated with the numbers of O. viverrini eggs/g faeces [with correlation coefficients (r) of 0.251, 0.121 and 0.142, respectively]. Although the serum levels of IgG were positively correlated with the urine levels of IgG (r=0.098), there was no significant relationship between the serum and urine levels of specific IgG(4) (r=0.051). When the 225 subjects investigated in the ELISA were divided according to whether they had no detectable Opisthorchis eggs in their faeces (N=57), or 1-100 (N=154), 101-1000 (N=5), 1001-1500 (N=5) or >1501 (N=4) eggs/g faeces, the serum and urine levels of specific IgG and the serum (but not urine) levels of specific IgG4 were also found to correlate significantly with the infection-intensity categories (with r-values of 0.550, 0.146 and 0.578, respectively). When the results of the faecal examinations were treated as the 'gold standard', the ELISA for the detection of (Opisthorchis-specific) serum IgG, serum IgG(4), urine IgG and urine IgG(4) had sensitivities of 99.2%, 23.1%, 43.0% and 45.9% and specificities of 93.0%, 29.6%, 45.9% and 67.2%, respectively. Although the study was limited by the small number of subjects with intense infections, it appears worth investigating urine samples for subclasses of specific IgG other than IgG(4).

Pathogen-specific IgG antibody levels in immunodeficient patients receiving immunoglobulin replacement do not provide additional benefit to therapeutic management over total serum IgG

Objectives: The current study aimed at evaluating the predictive value of serum IgG and IgG/IgM ratio measured on admission for steroid-resistant response after eight weeks of treatment in pediatric patients with idiopathic nephrotic syndrome (NS). Methods: The current cross sectional study was conducted on 69 children, including 41 patients with idiopathic NS and 28 healthy subjects as controls. Serum IgA, IgG, and IgM levels were measured in all subjects using immunoturbidimetric method. Results: The median serum IgA, IgG, and IgM levels were 1.15, 2.23, and 1.7 g/L, respectively. Serum IgA and IgG levels in patients were lower than controls (P < 0.001). In addition, 46.3% of children had steroid-resistant nephrotic syndrome (SRNS). IgG had a positive predictive value for SRNS (area under the curve (AUC) = 0.923, P < 0.001). With the cutoff point of 2.04 g/L, this test had the sensitivity and specificity of 89.5% and 95.5%, respectively. The IgG/IgM ratio also had a positive predictive value for SRNS (AUC = 0.892, P < 0.001). With the cutoff point of 1.64 g/L, this test had the sensitivity of and specificity of 89.5% and 81.8%, respectively. Conclusions: Serum IgG level and IgG/IgM ratio can be considered as predictive markers for steroid resistance in children first diagnosed with idiopathic NS.

BAL and Serum IgG Levels in Healthy Asymptomatic HIV-Infected Patients

Background: Increased serum antibodies against carbonic anhydrase II (CA-II Ab) or IgG4 levels have been reported in cases of autoimmune chronic pancreatitis (ACP). Aim: To assess the relevance of serum...

High pneumococcal serotype specific IgG, IgG1 and IgG2 levels in serum and the middle ear of children with recurrent acute otitis media receiving ventilation tubes

Association of serum IgG4 and soluble interleukin-2 receptor levels with epicardial adipose tissue and coronary artery calcification

BackgroundIn contrast to intense investigations of galactose-deficient immunoglobulin A (IgA)1 specific immunoglobulin G (IgG), little is known about the IgG subclasses in IgA nephropathy (IgAN). Low IgG4 levels in IgAN were noticed in our preliminary experiment. We aimed to verify the low IgG4 levels and investigate the related immune mechanism in IgAN.MethodsA total of 112 healthy controls (HC) and 112 newly diagnosed IgAN patients were enrolled in this study. Patients with idiopathic membranous nephropathy (IMN), minimal change disease (MCD), or lupus nephritis (LN) were selected as disease controls (DC) (n=122). Serum IgG4 and IgG levels were detected by enzyme-linked immunosorbent assay (ELISA). The IgG4+ B, T helper 1 (Th1), and Th2 cells were measured by flow cytometry. Receiver operating characteristic curves (ROC) were performed to evaluate the diagnostic value of IgG4.ResultsBoth IgG4 levels and IgG4/IgG in IgAN were lower than HC and DC (all P<0.001). Severe IgAN displayed lower IgG4 levels than mild IgAN (P=0.039). Patients with higher risk of renal progression (>50%) demonstrated lower IgG4 levels than lower-risk (≤15%) patients (P=0.019). The cutoff value of IgG4 in differentiating IgAN from HC and DC was 0.26 mg/mL [sensitivity 98.2%, specificity 82.4%, area under the curve (AUC): 0.941, P<0.0001] and 0.17 mg/mL (sensitivity 90.2%, specificity 85.2%, AUC: 0.937, P<0.0001), respectively. IgG4/IgG displayed similar diagnostic and differential ability. The IgG4+ B/B cells (P<0.0001) and Th2/Th (P=0.042) of IgAN were lower than HC.ConclusionsSerum IgG4 levels were low in IgAN. Lower IgG4 levels indicated more severe disease conditions and higher risk of renal progression. Low serum IgG4 seemed to be a potential diagnostic biomarker for IgAN. Decreased IgG4+ B cells and Th2 cells may contribute to the low IgG4 levels in IgAN.

IntroductionTo allow the identification of IgG4-related disease (IgG4-RD) from a subclinical phase as it is important to understand the risk of elevated serum IgG4 levels. We planned to evaluate serum IgG4 levels in the participants of the Nagasaki Islands Study (NaIS), a large-scale health checkup cohort study.MethodsThis study included 3,240 individuals who participated in the NaIS between 2016 and 2018 and consented to participate in the study. Serum IgG4, IgG, and IgE levels and human leukocyte antigen (HLA) genotyping results of the NaIS subjects as well as lifestyle habits and peripheral blood test results were analyzed. The magnetic bead panel assay (MBA) and the standard nephelometry immunoassay (NIA) were used to measure serum IgG4 levels. The data were evaluated using multivariate analysis to identify lifestyle and genetic factors associated with elevated serum IgG4 levels.ResultsSerum IgG4 levels measured with the NIA and MBA showed a tight positive correlation between the two groups (correlation coefficient 0.942). The median age of the participants in the NaIS was 69 years [63–77]. The median serum IgG4 level was 30.2 mg/dL [IQR 12.5–59.8]. Overall, 1019 (32.1%) patients had a history of smoking. When the subjects were stratified into three groups based on the smoking intensity (pack-year), the serum IgG4 level was significantly higher among those with a higher smoking intensity. Accordingly, the multivariate analysis identified a significant relationship between smoking status and serum IgG4 elevation.ConclusionIn this study, smoking was identified as a lifestyle factor correlating positively with elevated serum IgG4 levels.

IgG4-Related Lymphadenopathy: a Distinct Clinicopathological Entity That Is Associated with IgG4-Related Sclerosing Diseases

The incidence of thyroid nodules (TNs) has increased nowadays, and it is critical to properly differentiate between malignant and benign nodules to prevent unneeded thyroidectomy as well as complications related to surgery. IgG4 significantly contributes to various cancer-associated processes. The present study aimed to assess the value of serum IgG4 level in predicting malignancies in indeterminate thyroid nodules (ITN) among patients with and without autoimmune thyroid disease (AITD). A total of 67 patients with indeterminate cytology thyroid nodules (Bethesda III and IV, according to Bethesda system for reporting thyroid cytopathology) were selected. Preoperative serum thyroid profile, IgG4, anti-thyroglobulin (TG) and anti-thyroid peroxidase (TPO) antibody levels were determined. After total thyroidectomy, patients were categorized based on the postoperative histopathology outcome into two groups. Group (I): confirmed benign nodules (n=55) and Group (II): confirmed malignant TNs (n=12). IgG4 levels were significantly elevated among malignant TNs patients than in benign TNs patients, with a median (IQR) of 194.5 mg/dl (183 - 214) vs. 91 mg/dl (60 - 113), respectively (P=0.001). The cut-off value for differentiation between malignant and benign TNs was >180 mg/dl with a sensitivity of 75% and specificity of 100%. There was a significant positive correlation between thyroid antibodies and IgG4 levels (P=0.001). AITD patients had significantly higher level of IgG4 compared with those without AITD 189 mg/dl (153 - 208) vs 89 mg/dl (58 - 112), respectively (P =0.001). Eighty percent (12/15) of patients with AITD had malignant TNs with IgG4 >180 mg/dl, while 20% (3/15) of patients with benign TNs showed IgG4 levels < 180 mg/dl. In conclusion, IgG4 level can be proposed as a predictor of malignant TNs.

Antibodies IgG, IgA, and IgM to food antigens during the first 18 months of life in relation to feeding and development of atopic disease

Analysis of Ig subclass deficiency: First reported case of IgG2, IgG4, and IgA deficiency caused by deletion of Cα1, ψCγ, Cγ2, Cγ4, and Cε in a Mongoloid patient

Practical aspects of immunoglobulin replacement