Immunoglobulin G (IgG) and IgG subclass reference intervals in children, using Optilite® reagents

Grunewald, Olivier; López, Benjamín; Rogeau, Stéphanie; Deschildre, A.; Phrommavanh, Vassana; Lefort, M.; Moitrot, Emmanuelle; Gyselinckx, Dominique; Deleplancque, Anne‐Sophie; Lefèvre, Guillaume; Labalette, Myriam; Dubucquoi, Sylvain

doi:10.1515/cclm-2018-0001

Cited by 11 publications

(7 citation statements)

References 20 publications

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“…To the best of the authors' knowledge, intraindividual variation of serum IgG subclass concentrations has not previously been described. Further, only a few cross‐sectional studies on IgG subclass reference intervals in healthy individuals have been published 18–21 …”

Section: Introductionmentioning

confidence: 99%

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Time‐related variation in IgG subclass concentrations in a group of healthy Danish adults

Rasmussen

Sprogøe

Nielsen

et al. 2021

Immunity Inflam & Disease

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Introduction Immunoglobulin G subclass measurements are important for the diagnostic work‐up of immunodeficiencies and immunoglobulin G4 (IgG4) related diseases. It is currently unknown whether a single sampling is truly representative for an individual's IgG subclass concentrations. This study aimed to investigate whether IgG and IgG subclass concentrations in healthy individuals are stable over time. Method With a span of median 42 weeks, four samples from each of 54 (34M, 20F) healthy adult volunteers (24–66 years) were analyzed for IgG and IgG1–4 using turbidimetry. Concentrations were compared within and between individuals. Results IgG and IgG subclass concentrations followed either a normal (IgG, IgG1, and IgG3) or log normal (IgG2 and IgG4) distribution. Immunoglobulin 4 demonstrated by far the widest range of concentrations between individuals (670‐fold: 0.004–2.68 g/L). Immunoglobulin G subclass variations within individuals were expressed as pooled standard deviations (PSD). These ranged from 0.056 (IgG4) to 0.955 g/L (IgG) and correlated with mean concentration of IgG or the particular IgG subclass. As a consequence, the relative PSDs (i.e., PSD divided by mean IgG or IgG subclass concentration) fell within a narrow range: 5.82%–10.1%. Based on these numbers, the 95%‐upper one‐sided confidence limits for intraindividual IgG and IgG subclass variation was calculated to range from 9.82% (IgG2) to 16.9% (IgG4). Conclusion The study documents that IgG or IgG subclass concentrations within healthy individuals are very stable over at least 42 weeks. The expected variation for IgG4 concentrations at a 95% confidence level does not exceed ±16.9%.

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Section: Introductionmentioning

confidence: 99%

“…Further, only a few cross‐sectional studies on IgG subclass reference intervals in healthy individuals have been published. 18 , 19 , 20 , 21 …”

Section: Introductionmentioning

confidence: 99%

Time‐related variation in IgG subclass concentrations in a group of healthy Danish adults

Rasmussen

Sprogøe

Nielsen

et al. 2021

Immunity Inflam & Disease

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“…Patient data were selected using a direct sampling/ a posteriori approach and RIs were determined according to the Clinical and Laboratory Standards Institute (CLSI) EP28-A3c guidelines ( 11 , 12 ). The calculation method has been described in detail elsewhere ( 12 , 13 ). When the manufacturer had already published RIs for EDTA plasma samples, we applied the transference validity method described by the CLSI: 20 reference individuals were randomly selected (using the RAND function in Excel ® software) from our population and their analyte concentrations were compared with the manufacturer’s RIs ( 12 ).…”

Section: Methodsmentioning

confidence: 99%

“…Futhermore, the lower and upper reference limits (the 2.5 th and 97.5 th percentiles) and the corresponding 90% confidence intervals (CIs) were then calculated using a non-parametric method when the number of observations exceeded 120 or Horn and Pesce’s alternative, robust method when only a small number of observations (N < 120) were available ( 12 , 14 ). Finally, Harris and Boyd’s test was applied to determine whether the adult and paediatric age partitions were different enough to warrant separation ( 12 , 13 ). Harris and Boyd’s test compares a calculated z statistic with a critical value z*; if the calculated value exceeds z, then partitioning is recommended (see reference 12 for details of the z statistic calculations).…”

Section: Methodsmentioning

confidence: 99%

Classical pathway activity C3c, C4 and C1-inhibitor protein reference intervals determination in EDTA plasma

López

Bertier²,

Ledoult

et al. 2019

Biochem. med. (Online)

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Introduction: Reference intervals (RIs) for complement assays in EDTA plasma samples have not previously been published. The objectives of the present study were to validate and/or determine RIs for classical pathway (CP50) activity and C3c, C4 and C1 inhibitor protein (C1INH) assays and to assess the need for age-specific RIs in EDTA plasma. Materials and methods: We retrospectively evaluated a cohort of 387 patients attending our university hospital and known to be free of complement- modifying diseases. The need for age partitioning was assessed and RIs were calculated according to the CLSI protocol. Results: No need for age partitioning was evidenced for CP50 activity, C3c and C4 concentrations and RIs (90% CI) were calculated from the pooled data: 35.4 (33.1-37.2) to 76.3 (73.7-83.6) U/mL for CP50 activity, 0.80 (0.75-0.87) to 1.64 (1.59-1.72) g/L for C3c, and 0.12 (0.10-0.14) to 0.38 (0.36- 0.40) g/L for C4. Our results highlight a positive association between age and C1INH concentrations. We derived 3 age partitions (6 months to 30 years, 30-50 and > 50 years) and the related RIs: 0.20 (0.18-0.21) to 0.38 (0.36-0.40) g/L, 0.22 (0.20-0.24) to 0.39 (0.36-0.41) g/L and 0.25 (0.22-0.27) to 0.41 (0.40-0.43) g/L, respectively). Conclusions: The newly determined RIs for CP50 activity were higher than those provided by the manufacturer for EDTA plasma samples, whereas those for C3c and C4 RIs were similar to the values provided for serum samples. The C1INH concentration and activity were found to be associated with age and age-specific RIs are mandatory for this analyte.

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“…Pediatric AIP has a distinct presentation with features similar to Type 2 AIP in adults. In children, serum IgG and IgG 4 levels reach the same level as adults around the age of 10 55 . It is therefore necessary to consider not only the absolute value but also the age equivalent value as well as the ratio to the total IgG.…”

Section: Pathogenesis and Risk Factorsmentioning

confidence: 99%

Acute recurrent and chronic pancreatitis in children

Suzuki

Minowa

Isayama

et al. 2021

Pediatrics International

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Acute recurrent pancreatitis (ARP) is defined as two distinct episodes of acute pancreatitis (AP), whereas chronic pancreatitis (CP) is caused by persistent inflammation of the pancreas. In children they are caused by genetic mutations, autoimmune pancreatitis, congenital pancreatic abnormalities, and other conditions. Acute recurrent pancreatitis is frequently a precursor to CP, and both are thought to be on the same disease continuum. In particular, genetic factors are associated with early progression of ARP to CP. The diagnosis of CP, as in AP, is based on clinical findings, biochemical tests, and imaging studies. Findings of exocrine pancreatic dysfunction are also important in the diagnosis of CP. A step‐up strategy has become increasingly standard for the treatment of patients with CP. This strategy starts with endoscopic treatment, such as pancreatic sphincterotomy and stenting, and progresses to surgery should endoscopic therapy fail or prove technically impossible. Non‐opioid (e.g. ibuprofen / naproxen) and opioid (e.g. oxycodone) forms of analgesia are widely used in pediatric patients with AP or CP, whereas pancreatic enzyme replacement therapy may be beneficial for patients with abdominal pain, steatorrhea, and malnutrition. Despite the disparity in the age of onset, pediatric CP patients display some similarities to adults in terms of disease progress. To reduce the risk of developing pancreatic exocrine inefficiency, diabetes and pancreatic cancer in the future, clinicians need to be aware of the current diagnostic approach and treatment methods for ARP and CP and refer them to a pediatric gastroenterologist in a timely manner.

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Immunoglobulin G (IgG) and IgG subclass reference intervals in children, using Optilite® reagents

Cited by 11 publications

References 20 publications

Time‐related variation in IgG subclass concentrations in a group of healthy Danish adults

Time‐related variation in IgG subclass concentrations in a group of healthy Danish adults

Classical pathway activity C3c, C4 and C1-inhibitor protein reference intervals determination in EDTA plasma

Acute recurrent and chronic pancreatitis in children

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